Table of Content

18 November 2013, Volume 24 Issue 11

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Multiscale and multiparameter spatial distribution patterns of Seriphidium terraealbae and Artemisia songarica populations in Gurbantunggut Desert of Northeast China.

TAO Ye1,2, ZHANG Yuan-ming1, WU Xiao-bo1

2013, 24(11):  3019-3026. 

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The researches on the plant population spatial pattern were mostly based on 0-D plant point (0-D IND) or 0-D plant count, and only a few was based on the 2-D projective cover (2-D PC) and 3-D aboveground biomass (3-D AGB reflected by canopy volume). Until now, the plant population spatial distribution patterns incarnated by these parameters were still unclear. Taking the widely distributed small semishrubs Seriphidium terraealbae and Artemisia songarica in Gurbantunggut Desert of Northwest China as test objects, this paper studied the IND, PC, and AGB of each individual at two sampling plots. Through sixscale division of plot coordinate system with GIS, and by using aggregation analysis, coefficient of variation (CV), and a scaling exponent between the CV and six scales, the characteristics of the population spatial distribution patterns with the above mentioned parameters were comparatively analyzed. At all scales, the IND (except for the S. terraealbae population at 0.5 m scale) and the AGB of the two shrubs all presented a clumped distribution, and the aggregation intensity increased with increasing scale. However, the PC had a uniform distribution (except for the A. songarica population at 5 and 8 m scales). With increasing scale, the CV values of the two shrubs decreased. The absolute value of scaling exponent (k value) of the IND was higher than those of the PC and AGB, and there was no significant difference in the k values between the PC and AGB, indicating that the scale variation scope of the structural complexity of the IND was larger than that of the PC and AGB. The k value of each parameter for S. terraealbae was higher than that for A. songarica, which could be related to the populations’ interspecific relationship and plant size. In sum, the IND and AGB had  similar spatial patterns, while the PC and AGB had almost  same spatial pattern complexity and scale change characteristics.

Effects of nitrogen and phosphorus fertilization on litterfall production and nutrient dynamics in a Schima superba forest in Zhejiang Province of East China.

LU Yan1,2, ZHENG Ze-mei1,2, MEILIBAN Mamuti1,2, LU Jiang1,2, WANG Xi-hua1,2

2013, 24(11):  3027-3034. 

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In 2011, an investigation was made on the litterfall production and nutrient dynamics in a phosphorus-limited subtropical evergreen broadleaved forest dominated by Schima superba in Tiantong, Zhejiang Province of East China under different levels of nitrogen (N) and phosphorous (P) fertilization. After the N and P fertilization, the annual litterfall production ranged from 6.82 to 8.30 t·hm^-2·a^-1, with three peaks in May or June, August, and October, respectively. Under fertilization, the annual average N and P oncentrations of the litterfall (except the annual average N concentration under P fertilization) increased, and had a seasonal variation. There were no significant differences in the nitrogen return amount (60.05-71.47 kg·hm^-2·a^-1) and phosphorus return amount (2.94-3.93 kg·hm^-2·a^-1) of the litterfall among different treatments. As compared to the control, the N:P ratio of the litterfall under fertilization was higher at the beginning of the experiment (spring, 2011), but lower in the winter, 2011, indicating that nitrogen and phosphorus fertilization could alter the original nitrogen and phosphorus limited conditions of the studied forest ecosystem.

Effects of topography on seedling regeneration in a mixed broadleaved-Korean pine forest in Xiaoxing’an Mountains, Northeast China.

ZHAO Xue, LIU Yan-yan, JIN Guang-ze

2013, 24(11):  3035-3042. 

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To explore the responses of forest seedlings to topographic heterogeneity, nine hundreds of 4 m²(2 m×2 m) quadrats with perennial seedlings (H≥30 cm, DBH<1 cm) were installed in a 9 hm² plot in a typical mixed broadleaved-Korean pine forest in Xiaoxing’an Mountains. Based on the investigation data in 2006, 2008, and 2010, the effects of topography on the seedling establishment were studied. There were a total of 26 tree species in these quadrats. In 2006, 2008, and 2010, the total number of the tree seedlings was 4514, 6464, and 5611 individuals·hm^-2, respectively, among which, the seedlings of the top 10 species occupied >90% of the total. Topography had significant effects on the seedling distribution of the 8 major tree species. For Syringa reticulate var. mandshurica, Abies nephrolepis, Acer mono, Ulmus japonica, A. ukurunduense, Tilia amurensis, and A. tegmentosum, the spatial distribution of the seedlings was consistent with that of grown trees; but for Pinus koraiensis, the spatial distribution of seedlings was inconsistent with that of the grown trees. The mortality of S. reticulate var. mandshurica, A. nephrolepis, U. laciniata, A. tegmentosum, and T. amurensis seedlings was significantly correlated with the topography. The recruitment of S. reticulate var. mandshurica, U. japonica, P. koraiensis, A. nephrolepis, Fraxinus mandshurica, A. mono, and T. amurensis seedlings was also significantly correlated with the topography.

Species composition and main populations spatial distribution pattern in Korean pine broadleaved forest in Xiaoxing’an Mountains of Northeast China.

HOU Hong-ya, WANG Li-hai

2013, 24(11):  3043-3049. 

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Taking the Korean pine broadleaved forest in Liangshui Nature Reserve of Heilongjiang Province, Northeast China as test object, this paper studied the species composition and diameter class structure, and by using point pattern analysis, analyzed the spatial distribution pattern and spatial association of the main populations. In the Reserve, there were a total of 16 species with diameter greater than 1 cm in tree layer, and great differences were observed in the densities of main populations. Coniferous trees such as Pinus koraiensis and Abies nephrolepis were dominant. The diameter class structure of the populations presented as an inverse “J” curve, indicating a good regeneration across the community. The main populations were mostly in aggregated distribution pattern, except that the P. koraiensis populations at the scales of 19-21 m and 44 m as well as the Acer tegmentosum populations close to the largest research scale were in random distribution. The P. koraiensis populations at all research scales were approximately in random distribution, and had the minimum aggregation. A. nephrolepis, Tilia amurensis, and A. tegmentosum populations all presented a random distribution trend. Except that the P. koraiensis and A. nephrolepis at 2-3 m scale and the A. nephrolepis and A. tegmentosum populations at 37-81 m scale had significant positive association, no significant associations were observed between other populations. All the tree species presented an overall non-significant positive association.

Spatial variation of nonstructural carbohydrates in Betula platyphylla and Tilia amurensis stems.

ZHANG Hai-yan, WANG Chuan-kuan, WANG Xing-chang, CHENG Fang-yan

2013, 24(11):  3050-3056. 

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Taking the two diffuseporous tree species Betula platyphylla and Tilia amurensis in a temperate forest in Northeast China as test objects, this paper studied the spatial variation of the nonstructural carbohydrates (NSC) concentrations in the stem xylem  after leaffall. For the two tree species,  the concentrations of total nonstructural carbohydrate (TNC, soluble sugars plus starch) and soluble sugars  in the stem xylem decreased gradually with the increasing depth from cambium to pith, whereas the starch concentration showed little radial variation. There was still a substantial amount of NSC in the inner wood close to pith. The concentrations of the NSC in the two species stems decreased gradually from the stump to the breast height, and then increased vertically. The maximum concentrations of the TNC, soluble sugars, and starch occurred at different heights, depending on the species and the TNC components. The ratio of sugar to starch showed a contrasting vertical trend for the two species, i.e., increasing from the stump to the top for B. platyphylla, but decreasing for T. amurensis. The estimation error of the stem NSC storage was mainly from the axial variation, and then, from the radial variation of NSC concentration. The TNC concentration (1.0% dry mass) in the stem of shadeintolerant species B. platyphylla was significantly lower than that (4.3% dry mass) of shadetolerant species T. amurensis, which could be related to their different lifehistory strategies. Applying the sampling protocols  considering the axial and radial variations of NSC could effectively reduce the potential uncertainty in estimating the NSC storage at tree or stand level.

Net carbon exchange and its environmental affecting factors in a forest plantation in Badaling, Beijing of China.

TANG Xiang1, CHEN Wen-jing1, LI Chun-yi1, ZHA Tian-shan1,3, WU Bin1, WANG Xiao-ping2,3, JIA Xin1

2013, 24(11):  3057-3064. 

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By using eddy covariance technique, a year-round (November, 2011-October, 2012) continuous measurement of net ecosystem carbon dioxide exchange (NEE) was conducted in a 4year old mixed forest plantation in Badaling of Beijing. The forest plantation ecosystem was a net carbon sink in July and August, but a carbon source in the rest months. The monthly net carbon loss and uptake were the largest in April and July, respectively. The annual net ecosystem productivity was (-256±21) g C·m^-2·a^-1, in which, the ecosystem respiration was (950±36) g C·m^-2·a^-1, and the gross ecosystem productivity was (694±17) g C·m^-2·a^-1. The nighttime NEE increased exponentially with the soil temperature at 10 cm depth, with the estimated temperature sensitivity of ecosystem respiration (Q₁₀) being 2.2. During the growth season (May-September), the daytime NEE increased with photosynthetically active radiation (PAR) as described by the Michaelis-Menten rectangular hyperbola. The ecosystem quantum yield varied seasonally, ranging from 0.0219 μmol CO₂ ·μmol^-1 in May to 0.0506 μmol CO₂ ·μmol^-1  in July. The maximum carbon assimilation rate and the average daytime respiration followed the seasonal trends of PAR and air temperature. In July and August, vapor pressure deficit and soil moisture played a significant role in determining daytime NEE.

Estimation of carbonaceous gases emission from forest fires in Xiao Xing’an Mountains of Northeast China in 1953-2011.

HU Hai-qing1, LUO Bi-zhen1, WEI Shu-jing1,2, SUN Long1, WEI Shu-wei3, WEN Zheng-min2

2013, 24(11):  3065-3076. 

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Based on the forest resources investigation data and the forest fire inventory in 1953-2011, in combining with our field research in burned areas and our laboratory experiments, this paper estimated the carbonaceous gases carbon dioxide (CO₂), carbon monoxide (CO), methane (CH₄), and nonmethane hydrocarbons (NMHC) emission from the forest fires in Xiao Xing’an Mountains of Heilongjiang Province, Northeast China in 1953-2011. The total carbon emission from the forest fires in the Xiao Xing’an Mountains in 1953-2011 was 1.12×10⁷ t, and the annual emission was averagely 1.90×10⁵ t, accounting for 1.7% of the annual average total carbon emission from the forest fires in China. The emission of CO₂, CO, CH₄, and NMHC was 3.39×10⁷, 1.94×10⁵, 1.09×10⁵, and 7.46×10⁴ t, respectively, and the corresponding annual average emission was 5.74×10⁵, 3.29×10⁴, 1.85×10³, and 1.27×10³ t, accounting for 1.4%, 1.2%, 1.7%, and 1.1% of the annual carbonaceous gases emitted from the forest fires in China, respectively. The combustion efficiency and the carbon emission per unit burned area of different forest types decreased in order of coniferous forest > broadleaved forest > coniferous broadleaved mixed forest. Some rational forest fire management measures were put forward.

Effects of air temperature and soil moisture  on flavonoids accumulation in Ginkgo biloba leaves.

WANG Gui-bin, GUO Xu-qin, CHANG Li, CAO Fu-liang

2013, 24(11):  3077-3083. 

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Taking the 2-year-old Ginkgo biloba seedlings as test materials, a pot experiment was conducted in an artificial climate chamber to study the effects of air temperature and soil moisture  on the flavonoids accumulation in leaves. Three levels of air temperature (15/5 ℃, 25/15 ℃, and 35/25 ℃ day/night) and three levels of soil moisture  (55%-60%, 40%-45%, and 30%-35% of field capacity) were installed, yielding nine temperaturesoil moisture combinations. Under the three levels of soil moisture, the quercetin, kaempferol, isorhamnetin, and total flavonoids contents in the leaves were higher at 15/5 ℃ than at 25/15 ℃ and 35/25 ℃. Soil moisture  had minor effects on the flavonoids accumulation. The leaf kaempferol content was the highest, followed by quercetin and isorhamnetin. The total flavonoids yield per plant at 35/25 ℃ was higher than that at 15/5 ℃ and 25/15 ℃. It was suggested that to adopt appropriate soil covering and watering before harvesting to decrease the ambient temperature could benefit the enhancement of leaf flavonoids content and the improvement of per unit area flavonoids production in G. biloba leafharvesting plantation.

Effects of different drip irrigation modes on root distribution of wine grape ‘Cabernet Sauvignon’ in desert area of Northwest China.

MAO Juan, CHEN Bai-hong, CAO Jian-dong, WANG Li-jun, WANG Hai, WANG Yan-xiu

2013, 24(11):  3084-3090. 

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To study the effects of different drip irrigation modes on the wine grape root distribution is the basis of formulating fertilization, irrigation, and overwintering management practices for wine grape. Taking the wine grape “Cabernet Sauvignon” as test material, this paper studied the effects of different watersaving irrigation modes (drip irrigation under straw mulching, drip irrigation under plastic mulching, doubletube drip irrigation, and singletube drip irrigation) on the root distribution of wine grape in the desert area of Northwest China, with the conventional furrow irrigation as the control. The root system of the “Cabernet Sauvignon” was distributed from 0 to 70 cm vertically, and from 0 to 120 cm horizontally. With doubletube drip irrigation, the root amount was the largest (138.3 roots per unit profile), but the root vertical distribution scope was narrowed by 20 cm, as compared to the control. Drip irrigation with straw mulching increased the root amount significantly, and increased the root horizontal distribution scope by 9.1%, as compared to the control. No significant difference was observed in the root number and root horizontal distribution scope between the drip irrigation under plastic mulching and the control, but the root vertical distribution scope with the drip irrigation under plastic mulching decreased by 20 cm.  Singletube drip irrigation increased the root number significantly, but had lesser effects on the root vertical or horizontal distribution, as compared to the conventional irrigation. It was suggested that the drip irrigation under straw mulching could be the best water-saving practice for the wine grape “Cabernet Sauvignon” in the study area.

Effects of different long-term fertilization patterns on Fuji apple yield, quality, and soil fertility on Weibei Dryland, Shaanxi Province of Northwest China.

ZHAO Zuo-ping1,2, TONG Yan-an1, LIU Fen1, WANG Xiao-ying1

2013, 24(11):  3091-3098. 

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A 7-year (2003-2010) located field experiment was conducted to evaluate the effects of different longterm fertilization patterns on the Fuji apple yield, quality, and soil fertility on the Weibei Dryland, Shaanxi Province of Northwest China. Seven treatments were installed, i.e., no fertilization (CK), inorganic P and K fertilization (PK), inorganic N and K fertilization (NK), inorganic N and P fertilization (NP), inorganic N, P, and K fertilization (NPK), swine manure (M), and half inorganic N, P, and K combined with half swine manure (NPKM). Each treatment had three replications. Fertilization increased the apple yield. The average yield in the 7 years under fertilization was increased by 14.4%-63.8%, as compared to the CK. The average yield decreased in the order of NPKM＞NPK≥M＞NP≥NK＞PK＞CK. In treatments NPKM, M, and NPK, the fruit sugar/acid (S:A) ratio, vitamin C, soluble solid, and hardness tended to be increased with time, with a smaller yearly fluctuation in treatments NPKM and M. In treatment NPKM, the S:A ratio and vitamin C increased by 30.9% and 17.5%, respectively after five years, as compared to the CK. Long-term rational fertilization increased the soil organic matter (SOC) content in 0-20 cm layer, with the largest increment in treatments NPKM and M (28.8% and 29.3%, respectively). The soil available N, P, and K contents in all layers in treatments NPK, NPKM, and M increased significantly, and the soil available N content in 0-20, 20-40, and 40-60 cm layers in treatment NPK was increased by 22.7%, 37.3%, and 53.4%, respectively. As compared to treatment NPK, the soil available P content in treatment NPKM was increased by 18.7%. In all fertilization treatments, the soil available P content was significantly higher in upper layer than in lower layer.

Effects of shading on dry matter accumulation and nutrient absorption of summer maize.

CUI Hai-yan, JIN Li-bin, LI Bo, DONG Shu-ting, LIU Peng, ZHAO Bin, ZHANG Ji-wang

2013, 24(11):  3099-3105. 

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Taking summer maize cultivars Zhenjie 2 (ZJ2), Denghai 605 (DH605), and Zhengdan 958 (ZD958) as test materials, a field trial was conducted to study the effects of shading on the dry matter accumulation and nitrogen (N), phosphorus (P) and potassium (K) absorption of summer maize. Four treatments were installed, i.e., shading from flowering stage to maturity stage (S₁), shading from sixleaf stage to flowering stage (S₂), shading all through the growth season (S₃), and no shading (CK). After shading, the grain yield and dry matter accumulation decreased significantly, and the decrement was related to shading period, showing S₃>S₁>S₂. The grain yield in treatments S₁, S₂, and S₃ was averagely 61.6%, 25.3%, and 92.8% lower than that of CK, respectively, indicating that the effects of shading after flowering were greater than those of shading before flowering. The responses of different cultivars to shading presented a similar trend. The nutrient absorption of summer maize before flowering stage showed K>N>P, and the nutrient absorption amount of whole plant showed N>K>P. After shading, the N and P absorption decreased significantly. The plant relative N and P absorption in different treatments had somewhat increase, because the decrement of dry matter accumulation after shading was larger than that of N and P absorption, as compared with the control. After shading, the plant K absorption decreased significantly, and the decrement in S₂ was larger than that of dry matter accumulation. Shading before flowering stage had larger effects on the plant K absorption than on the N and P absorption.

 

Present situation of rice fertilization in Qin-Ba mountainous area of southern Shaanxi, China.

WANG Xiao-ying1,2, LIU Fen1,2, TONG Yan-an1,2, ZHAO Zuo-ping1,3

2013, 24(11):  3106-3112. 

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In order to understand the present situation of rice fertilization and the existing problems in the farmers’ nutrient resources input in the Qin-Ba mountainous area of southern Shaanxi, the survey data from 2854 households in 11 counties of this area in the project “soil testing and formulated fertilization in 2006-2009” were analyzed and evaluated, and the countermeasures for the existing problems in the farmers’ nutrient resources input were proposed. In the study area, the average rice yield was 7822 kg·hm^-2 per year, and the ratio of the households obtained the medium level yield was up to 50.9%. The input of the total fertilizers N, P₂O₅, K₂O was 169, 68, and 54 kg·hm^-2, and the chemical fertilizer rate was 159, 62, and 45 kg·hm^-2, with the partial factor productivity (PFP) of the N, P₂O₅, and K₂O being 51.52, 135.69, and 158.26 kg·kg^-1, respectively. According to  the nutrient fertilization level, the proportion of the households fertilized with rational level of chemical N, P₂O₅, and K₂O occupied 48.0%, 42.4%, and 7.2%, that of the households fertilized with excessive level was 22.6%, 11.2%, and 0.6%, and the proportion of the households fertilized with insufficient level occupied 29.4%, 46.5%, and 92.2%, respectively. The rice yield in the Qin-Ba mountainous area could be increased by 77 thousand tons if the households fertilizing with insufficient level of chemical NPK fertilizers increased the fertilization rate to a rational level. The existing problems in the farmers’ nutrient resources input were mainly the coexistence of excessive and insufficient application of nitrogen and phosphate fertilizers and the insufficient input of potassium fertilizer and organic manure. In the rice fertilization in this area, the focus would be the balanced application of nitrogen and phosphate fertilizers, the increase of the fertilization rates of potassium fertilizer and organic manure, and the increase of top dressing, especially potassium.

Effects of exogenous silicon on the pollination and fertility characteristics of hybrid rice under heat stress during anthesis.

WU Chen-yang1,2, CHEN Dan1, LUO Hai-wei3, YAO Yi-min1, WANG Zhi-wei1, TSUTOMU Matsui4, TIAN Xiao-hai1,2

2013, 24(11):  3113-3122. 

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Taking two mediummaturing indica rice hybrids Jinyou 63 and Shanyou 63 as test materials, this paper studied the effects of applying silicon fertilizer on the flag leaf chlorophyll content, photosynthetic properties, antioxidant enzyme activities, malondialdehyde (MDA) content, pollen vigor, anther acid invertase activity, pollination, and seedsetting of hybrid rice under the heat stress during anthesis. This study was conducted in pots and under growth chamber. Soluble solution of silicon fertilizer applied as Na₂SiO₃·9H₂O was sprayed on the growing plants after early jointing stage, with three times successively and at an interval of one week. The pots were then moved into growth chamber to subject to normal temperature vs. high temperature (termed as heat stress) for five days. In treatment normal temperature, the average daily temperature was set at 26.6 ℃, and the maximum daily temperature was set at 29.4 ℃; in treatment high temperature, the average and the maximum daily temperature were set at 33.2 ℃ and 40.1 ℃, respectively. As compared with the control, applying silicon increased the flag leaf chlorophyll content significantly, improved the net photosynthetic rate and stomatal conductance, decreased the accumulative intercellular CO₂ concentration, improved the leaf photosynthesis, reduced the MDA content, and improved the activities of SOD, POD and CAT under heat stress. In addition, applying silicon improved the anther acid invertase activity and the pollen vigor, increased the anther basal dehiscence width, total number of pollination per stigma, germinated number, germination rate of pollen, and percentage of florets with more than 10 germinated pollen grains, decreased the percentage of florets with fewer than 20 germinated pollen grains, and thus, alleviated the fertility loss of Jinyou 63 and Shanyou 63 under heat stress by 13.4% and 14.1%, respectively. It was suggested that spraying exogenous silicon in the early growth period of rice could mitigate the decrease of seedsetting at flowering stage, and improve the heat resistance of hybrid rice.

Mechanisms of subspecies differentiation in a filial generation of rice indica-japonica hybridization under different ecological conditions.

WANG He-tong1，2, JIN Feng1, JIANG Yi-jun3, LIN Qing-shan4, XU Hai1, CHEN Wen-fu1, XU Zheng-jin1

2013, 24(11):  3123-3130. 

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Indica-japonica hybridization is one of the most important breeding methods in China, whereas identifying subspecies differentiation mechanisms is the key in indica-japonica hybridization breeding. By using InDels (Insert/Deletion) and ILPs (Intron Length Polymorphism), an analysis was made on the F₆ populations derived from the hybridization of indica-japonica (Qishanzhan/Akihikari) planted in Liaoning and Guangdong provinces and generated by bulk harvesting (BM), singleseed descent methods (SSD), and pedigree method (PM). No segregation distortion was observed for the BM and SSD populations. The frequency distribution of japonica kinship percentage (Dj) was concentrated in 40%-60%. The PM populations in the two provinces presented indicadeviated distribution (30%-55%), with significant difference between Guangdong (38%) and Liaoning (42%). In addition, there was a significant positive correlation between the Dj and the kinship of functional gene regions in the BM and SSD populations. However, part of the positive correlation was broken in the PM populations that showed a regular distribution in the genotype patterns of indica and japonica loci. The above results demonstrated that artificial selection could be the main factor affecting the population differentiation in indica-japonica hybridization, and, with the synergistic effect of natural selection, induced the phenomenon of segregation distortion. There existed a close relationship between the differentiation of subspecies and the important agronomic traits, which could be the main reason why indica-japonica hybridiation breeding could not achieve the expected effect of combining the two subspecies advantages.

Photosynthetic and water physiological characteristics of weedy rice in northern China.

GAO Qi, MA Dian-rong, KONG De-xiu, WANG Wen-jia, TONG Hui, ZHAO Ming-hui, XU Zheng-jin, CHEN Wen-fu

2013, 24(11):  3131-3136. 

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Weedy rice is an important germplasm source of rice, which has the characteristics of cold, drought, and barren tolerance. Taking 88 accessions of weedy rice and 4 varieties of cultivated rice in northern China as test materials, this paper studied the photosynthetic characteristics (photosynthetic rate, transpiration rate, and stomatal conductance), water physiological characteristics, and their interrelationships of weedy rice in northern China. There existed greater differences in the photosynthetic and water physiological characteristics among the weedy rice accessions, possessing abundant diversity. The photosynthetic rate of the accessions was from 12.47 μmol CO₂·m^-2·s^-1 to 28.67 μmol CO₂·m^-2·s^-1, and the instantaneous water use efficiency was from 1.39 mg·g^-1 to 3.40 mg·g^-1. Among the photosynthetic parameters, intercellular CO₂  concentration had the smallest variable coefficient, while stomatal conductance had the largest one. The photosynthetic rate had significant conic relationships with transpiration rate and stomatal conductance, and had a linear relationship with intercellular CO₂ concentration. The significant conic relationships also existed between the instantaneous water use efficiency and the transpiration rate and stomatal conductance. The excellent features of weedy rice could be used to improve the cultivated rice varieties.

Effects of mulching on soil moisture in a dryland winter wheat field, Northwest China.

FAN Ying-dan1, CHAI Shou-xi1,CHENG Hong-bo2, CHEN Yu-zhang1, YANG Chang-gang1, HUANG Cai-xia3, CHANG Lei1, PANG Lei1

2013, 24(11):  3137-3144. 

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This paper studied the effects of different mulching modes on the soil moisture in a semiarid rainfed area of Loess Plateau, Northwest China. Seven treatments were installed, i.e., mulching plastic film in summer (T₁), mulching plastic film in autumn (T₂), mulching 5 cm long wheat straw in summer (T₃), mulching whole wheat straw in summer (T₄), mulching plastic film in summer plus wheat straw (T₅), mulching used plastic film after harvest (T₆), and unmulching (CK). In T₆, the soil moisture  in different layers at different crop growth stages was all higher than that in CK. In the other five mulching treatments, the soil moisture  in 0-90 cm layer before flowering stage was obviously higher, but that in 0-90 cm layer after flowering stage and in 90-200 cm layer during the whole growth season was lower than that of CK. The soil moisture  in 0-200 cm layer in T₆ during the whole growth period was significantly higher than that in CK, with a difference of 0.9%, but the soil moisture  in 0-200 cm layer in other mulching treatments was lower. As compared with plastic film mulching, straw mulching increased the soil moisture  in 0-200 cm layer. The soil moisture  under mulching with used plastic film after harvest was higher than that under mulching with new plastic film. As compared to CK, the grain yield of winter wheat with plastic film mulching was increased by 20.3%-29.0%, and that with straw mulching was increased by 5.0%-16.7%. There was a significant positive correlation between the crop productivity and the soil water consumption during the growth period (r=0.77^*).

Effects of plastic film mulching with double ridges and furrow planting on soil moisture and temperature and soybean yield on a semiarid dryland of Gansu Province, Northwest China.

YANG Feng-ke1,3, WANG Li-ming2,3, ZHANG Guo-hong2,3

2013, 24(11):  3145-3152. 

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Taking soybean cultivar Jindou 23 as test object, a field experiment was conducted at the Zhenyuan experimental station of Gansu Academy of Agricultural Sciences to study the effects of various plastic mulching treatments on the soil moisture and temperature and soybean grain yield on a semiarid dryland of Northwest China. Four treatments were installed, i.e., plastic film mulching with double ridges and furrow planting (FMRFC), plastic film mulching without ridges and with furrow planting (FMFC), plastic film mulching with strip planting (FMSC), and no mulch strip planting (NMSC, CK). During the drought year (the precipitation in soybean growth period was 246.3 mm) and wet year (407 mm), the daily soil temperature in 0-20 cm layer in all mulching treatments varied in “S” shape, and its fluctuation became smaller with soybean growth. The mulching treatments raised the daily average soil temperature in 0-20 cm layer by an average of 0.5-2.5 ℃ from the seedling (VE-V3) to seed filling (R6) stage, with the average soil temperature in whole growth period raised by 1.3-1.6 ℃. Both in dry year and in wet year, mulching treatments promoted the soil moisture consumption in 0-120 cm layer by soybean, but increased the average soil moisture content and water storage in 0-200 cm layer by 1.2%-1.4% and 62.7-70.3 mm, respectively. As compared to CK, treatments FMRFC and FMFC had significant effects in improving the soil temperature and moisture environment in dry year, and greatly improved the yield
related traits such as plant height, branching number, pods per plant, and 100-seed mass. FMRFC increased the yield by 27.7%-51.1% and raised the water use efficiency (WUE) by 47.7%-56.3%, whereas FMFC increased the yield by 10.2%-25.2% and raised the WUE by 33.3%-35.4%, as compared to CK. It was suggested that FMRFC and FMFC could be the most efficient planting systems for the soybean production in the dryland farming of Northwest China.

Optimal irrigation index for cotton drip irrigation under film mulching based on the evaporation from pan with constant water level.

SHEN Xiao-jun1, ZHANG Ji-yang1, SUN Jing-sheng1, GAO Yang1, LI Ming-si2, LIU Hao1, YANG Gui-sen3

2013, 24(11):  3153-3161. 

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A field experiment with two irrigation cycles and two irrigating water quotas at squaring stage and blossoming-boll forming stage was conducted in Urumqi of Xinjiang Autonomous Region, Northwest China in 2008-2009, aimed to explore the high-efficient irrigation index of cotton drip irrigation under film mulching. The effects of different water treatments on the seed yield, water consumption, and water use efficiency (WUE) of cotton were analyzed. In all treatments, there was a high correlation between the cotton water use and the evaporation from pan installed above the plant canopy. In high-yield cotton field (including the treatment T₄ which had 10 days and 7 days of irrigation cycle with 30.0 mm and 37.5 mm of irrigating water quota at squaring stage and blossoming-boll forming stage, respectively in 2008, and the treatment T₁ having 7 days of irrigation cycle with 22.5 mm and 37.5 mm of irrigating water quota at squaring stage and blossoming-boll forming stage, respectively in 2009), the pancrop coefficient (K_p) at seedling stage, squaring stage, blossoming-boll forming stage, and boll opening stage was 0.29-0.30, 0.52-0.53, 0.74-0.88, and 0.19-0.20, respectively. As compared with the other treatments, T₄ had the highest seed cotton yield (5060 kg·hm^-2) and the highest WUE (1.00 kg·m^-3) in 2008, whereas T₁ had the highest seed cotton yield (4467 kg·hm^-2) and the highest WUE (0.99 kg·m^-3) in 2009. The averaged cumulative pan evaporation in 7 days and 10 days at squaring stage was 40-50 mm and 60-70 mm, respectively, and that in 7 days at blossoming-boll forming stage was 40-50 mm. It was suggested that in Xinjiang cotton area, irrigating 45 mm water for seedling emergence, no irrigation both at seedling stage and at boll opening stage, and irrigation was started when the pan evaporation reached 45-65 mm and 45 mm at squaring stage and blossomingboll stage, respectively, the irrigating water quota could be determined by multiplying cumulative pan evaporation with K_p (the K_p was taken as 0.5, 0.75, 0.85, and 0.75 at squaring stage, early blossoming, full-blossoming, and late blossoming stage, respectively), which could be the high efficient irrigation index to obtain high yield and WUE in drip irrigation cotton field and to save irrigation water resources.

Characteristics of soil phosphorous loss under different ecological planting patterns in hilly red soil regions of southern Hunan Province, China.

2013, 24(11):  3162-3168. 

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Taking a large  standard runoff plot on a red soil slope in Qiyang County, southern Hunan Province as a case, this paper studied the surface soil phosphorus loss characteristics in the hilly red soil regions of southern Hunan under eight ecological planting patterns. The phosphorus loss from wasteland (T₁) was most serious, followed by that from natural sloped cropping patterns (T₂ and T₃), while the phosphorus loss amount from terrace cropping patterns (T₄-T₈) was the least, only occupying 9.9%, 37%, 0.7%, 2.3%, and 1.9% of T₁, respectively. The ecological planting patterns directly affected the forms of surfacelost soil phosphorus, with the particulate phosphorus (PP) as the main lost form. Under the condition of rainstorm (daily rainfall >50 mm), rainfall had lesser effects on the phosphorus loss among different planting patterns. However, the phosphorus loss increased with increasing rain intensity. The surface soil phosphorus loss mainly occurred from June to September. Both the rainfall and the rain intensity were the factors directly affected the time distribution of surface soil phosphorus loss in hilly red soil regions of southern Hunan.

Spatial variability of soil nutrients and their relations with rice yield at village scale in karst mountainous area of Guizhou Province, Southwest China.

LI Yun, FENG Yue-hua, WU Biao, WANG Xiao-yan, JI Hong-ting, LI Chuan-wei

2013, 24(11):  3169-3178. 

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By using geostatistics methods, an investigation was conducted on the spatial variability of soil pH, organic matter, total N, P, and K, and available N, P, K, Cu, Zn, Fe, and Mn and their relations with rice yield in Wenxing Village, Anshun City of Guizhou Province, Southwest China. The C₀/(C₀+C) ratios for the soil pH, total P, and available N, P, K, and Cu and the rice yield components were lower than 25%, indicating their strong spatial correlations, while the C₀/(C₀+C) ratios for the soil organic matter, total N and K, and available Zn, Fe, and Mn and the rice yield  were 25%-75%, showing a medium spatial correlation. Of all the soil nutrients, the soil available K had the closest relation with rice yield (r=0.4669, P<0.0001).The direct path coefficients of the soil available N, K and P to the effective panicle and thousand-grain mass were positive, in line with the partial correlation analysis. The Kriging interpolation showed that the soil organic matter, total N, and available N, K, Cu, and Zn contents presented a decreasing trend from the southwest to northeast, but the rice yield was higher in the northwest and southeast of the Wenxing Village.

Spatial heterogeneity of surface soil mineral components in a small catchment in Karst peak-cluster depression area, South China.

GAO Peng1,2,3, FU Tong-gang1,2,3, WANG Ke-lin1,2, CHEN Hong-song1,2, ZENG Fu-ping1,2

2013, 24(11):  3179-3184. 

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A total of 163 soil samples (0-20 cm layer) were collected from the grid sampling plots (80 m×80 m) in Huanjiang Observation and Research Station of Karst Ecosystem in a small catchment in Karst clusterpeak depression area, South China. By using classical statistics and geostatistics, the spatial heterogeneity of mineral components (SiO₂, Fe₂O₃, CaO, MgO, Al₂O₃, MnO, and TiO₂) in the soils were studied. The contents of the  seven soil mineral components  in the study area differed greatly, being in the order of SiO₂>Al₂O₃>CaO>MgO>Fe₂O₃>TiO₂>MnO, and the variance coefficients also varied obviously, in the order of CaO>MgO>Fe₂O₃>TiO₂>SiO₂>Al₂O₃>MnO. The seven mineral components accounted for 69.4% of the total soil mass. The spatial patterns and the fittest models of the seven soil mineral components differed from each other. All the seven soil mineral components had a strong spatial autocorrelation, with shorter variation ranges and stronger spatial dependence. The Kriging contour maps indicated that the distribution patterns of soil SiO₂, Fe₂O₃, Al₂O₃, MnO, and TiO₂ were similar, being higher in south and east, lower in north and west, higher in depression, and lower in slope, while the distribution patterns of soil CaO and MgO were in adverse. Natural conditions (vegetation, bare rock rate, slope degree, and slope aspect, etc.) and human disturbance were the most important factors affecting the spatial patterns of the soil mineral components.

Hyper spectral estimation method for soil alkali hydrolysable nitrogen content based on discrete wavelet transform and genetic algorithm in combining with partial least squares (DWT-GA-PLS).

CHEN Hong-yan1, ZHAO Geng-xing1, LI Xi-can2, WANG Xiang-feng3, LI Yu-ling4

2013, 24(11):  3185-3191. 

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Taking the Qihe County in Shandong Province of East China as the study area, soil samples were collected from the field, and based on the hyperspectral reflectance measurement of the soil samples and the transformation with the first deviation, the spectra were denoised and compressed by discrete wavelet transform (DWT), the variables for the soil alkali hydrolysable nitrogen quantitative estimation models were selected by genetic algorithms (GA), and the estimation models for the soil alkali hydrolysable nitrogen content were built by using partial least squares (PLS) regression. The discrete wavelet transform and genetic algorithm in combining with partial least squares (DWT-GA-PLS) could not only compress the spectrum variables and reduce the model variables, but also improve the quantitative estimation accuracy of soil alkali hydrolysable nitrogen content. Based on the 1-2 levels low frequency coefficients of discrete wavelet transform, and under the condition of large scale decrement of spectrum variables, the calibration models could achieve the higher or the same prediction accuracy as the soil full spectra. The model based on the second level low frequency coefficients had the highest precision, with the model predicting R² being 0.85, the RMSE being 8.11 mg·kg^-1, and RPD being 2.53, indicating the effectiveness of DWT-GA-PLS method in estimating soil alkali hydrolysable nitrogen content.

Characteristics of seasonal drought and its adaptation in southern China under the background of global climate change.Ⅵ. Optimized layout of cropping system for preventing and avoiding drought disaster.

SUI Yue1,2, HUANG Wan-hua1,3, YANG Xiao-guang1, LI Mao-song4

2013, 24(11):  3192-3198. 

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Southern China is an important agricultural planting region of China, but the seasonal drought severely impacted the regional agricultural production. Based on the 1981-2007  meteorological data from 13 typical meteorological stations in the seasonal drought areas in southern China and the data of related crops growth period and yield, three precipitation year types (drought year, normal year, and wet year) were classified based on the yearly precipitation, and by using five indices (coupling degree of water requirement and precipitation during crop water critical stages, meteorological crop yield, output value per unit area, and water use efficiency and precipitation during whole growth period), the comprehensive benefit of all possible cropping patterns in each typical region was evaluated, and the optimal cropping patterns in the different regions of southern China in different precipitation years were obtained. In the semiarid region, the optimal cropping patterns in dry year included potatomaizesweet potato and winter wheatricesweet potato. In the semihumid region and during dry year, winter wheatricesweet potato was the best choice, and rape seedricesweet potato was the second one. In the warm and humid region (the typical region where seasonal drought happened), the best cropping pattern in Jiangnan area in different precipitation years was potatodouble cropping rice, and the suitable patterns in southwest area were the triple cropping systems with droughtresistant crops, such as winter wheatricesweet potato, winter wheatmaizesweet potato, and potato-double cropping rice. From the aspect of maximally utilizing water and heat resources, triple cropping would be the best choice, with the rice and upland crop rotation as the main and with the rice arranged in pairs in wet year.

Simulation of leaf inclination angle distribution of main tree species in Daxing’an Mountains of China based on the Campbell ellipsoid distribution function.

WANG Xu-peng, FAN Wen-yi, WEN Yi-bo

2013, 24(11):  3199-3206. 

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Leaf inclination angle distribution directly decides the amount of radiation interception by vegetation canopy, and also, decides the size and direction of the incident radiation, being the key parameter in quantitative remote sensing. This paper simulated the leaf inclination angle distribution of the main tree species in Daxing’an Mountains forest region based on the Campbell ellipsoid distribution model and iterative method, and quantitatively analyzed the fitting results of canopy with and without leaf stratification as well as the effects of tree age group on the leaf inclination angle distribution. For the test 6 main tree species, the leaf inclination angle distribution was in planophile shape, and the mean leaf inclination angle was smaller for coniferous tree than for broadleaved tree. Whether with or without stratify, the fitting result and the measured result were basically identical. For Betula platyphylla and Larix gmelinii, the correlation coefficient between the simulated and measured values was 0.8268 and 0.8192, and the root mean square error was 3.7% and 4.3% respectively, indicating that the Campbell model was reliable applied for forest canopy. Considering the effects of tree age group, though the leaf inclination angle distribution trend with leaf stratification had no correlation with age group, the mean leaf inclination angle of young L. gmelinii was relatively smaller than that mature one, suggesting that age group had positive effects on the numerical design of leaf inclination angle distribution and negative effects on the numerical design of extinction coefficient.

Climatic suitability model for spring maize in Northeast China.

HOU Ying-yu, ZHANG Yan-hong, WANG Liang-yu, LU Hou-quan, SONG Ying-bo

2013, 24(11):  3207-3212. 

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Crop growth is a continuous and dynamic process, and thus, the optimal meteorological indices for crop growth also change continuously. In this paper, the estimation algorithms of the daily available precipitation and the temporal interpolation methods of meteorological indices for crop growth were developed, and the climatic suitability model at daily scale was established, which was tested by the spring maize data of agro-meteorological stations in Northeast China. The simulated climatic suitability had significantly positive correlations with the height and 100-grain mass of spring maize. The correlation coefficient (R²) between the climatic suitability and the spring maize height was over 0.58 at vegetative growth stage, and over 0.45 at reproductive growth stage. The established climatic suitability model at daily scale could objectively reflect the interactions between crop growth and meteorological factors at vegetative growth stage and reproductive growth stage.

Monitoring of soil salinization in Northern Tarim Basin, Xinjiang of China in dry and wet seasons based on remote sensing.

YAO Yuan, DING Jian-li, ZHANG Fang, WANG Gang, JIANG Hong-nan

2013, 24(11):  3213-3220. 

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Soil salinization is one of the most important eco-environment problems in arid area, which can not only induce land degradation, inhibit vegetation growth, but also impede regional agricultural production. To accurately and quickly obtain the information of regional saline soils by using remote sensing data is critical to monitor soil salinization and prevent its further development. Taking the Weigan-Kuqa River Delta Oasis in the northern Tarim River Basin of Xinjiang as test object, and based on the remote sensing data from Landsat-TM images of April 15, 2011 and September 22, 2011, in combining with the measured data from field survey, this paper extracted the characteristic variables modified normalized difference water index (MNDWI), normalized difference vegetation index (NDVI), and the third principal component from K-L transformation (K-L₃). The decision tree method was adopted to establish the extraction models of soil salinization in the two key seasons (dry and wet seasons) of the study area, and the classification maps of soil salinization in the two seasons were drawn. The results showed that the decision tree method had a higher discrimination precision, being 87.2% in dry season and 85.3% in wet season, which was able to be used for effectively monitoring the dynamics of soil salinization and its spatial distribution, and to provide scientific basis for the comprehensive management of saline soils in arid area and the rational utilization of oasis land resources.

Characteristics of evapotranspiration in an alpine shrub meadow in Haibei, Qinghai of Northwest China.

ZHENG Han1,2, WANG Qiu-feng1, LI Ying-nian3, ZHU Xian-jin1

2013, 24(11):  3221-3228. 

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Evapotranspiration (ET) is an important component of hydrological cycle of terrestrial ecosystem. To study the seasonal and interannual ET variation patterns of typical ecosystems is essential to better understand the water cycle process and to provide reference for the rational utilization of water resources. By using eddy covariance method, this paper studied the seasonal and interannual variation characteristics of ET and water budget in an alpine shrub meadow ecosystem in Haibei of Qinghai from 2003 to 2011. There was an obvious seasonal variation of ET in the study area in 2003-2011, with the maximum (4.4-5.7 mm·d^-1) in the vigorous growth season (July-August) and the minimum (0.09±0.04 mm·d^-1) in January or December. The annual ET varied greatly among the nine consecutive years, being 451.3 mm in 2010 and 681.3 mm in 2007. More than 70% of the annual ET occurred in the growth season from May to September. The average ratio of annual ET to  annual precipitation was 1.06±0.17, indicating that the water budget of this ecosystem was nearly balanced at year scale, and almost all the precipitation was released into atmosphere by ET.

Area changes of emergent herbaceous wetlands in relation to water level in East Dongting Lake, China in 1989-2011.

TANG Yue1,2, XIE Yong-hong1, LI Feng1, CHEN Xin-sheng1

2013, 24(11):  3229-3236. 

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Based on multitemporal Landsat MSS/TM/ETM⁺ images, and by using decision tree method, this paper extracted the areas of emergent herbaceous wetlands with different water levels in 1989-2011 in the East Dongting Lake, China. The change characteristics and change trends of the emergent herbaceous wetlands areas were investigated based on the DEM data and the daily water level data from the Chenglingji Hydrological Station. The area of the emergent herbaceous wetlands was significantly affected by water level (R²=0.875, P<0.001), presenting a significant linear relationship between the two. Moreover, the emergent herbaceous wetlands area decreased with increasing water level. The higher the water level, the smaller the effects of the water level on the emergent area were. The emergent area changed regularly with water level. In January-July, water level increased, and the emergent area decreased; in July-December, it was opposite. In 1989-2011, the areas of emergent herbaceous wetlands had a continual increase. The newly emergent herbaceous wetlands area was mainly transformed from mudflat. The emergent herbaceous wetlands expansion was the co-effects of the increase of the emergent herbaceous wetlands areas at different elevations, and the rapid expansion of the emergent herbaceous wetlands in low bottomland (22-25 m of Yellow Sea elevation) played the most important role in the expansion. The change of water level at different elevations was the dominant cause for the changes of emergent herbaceous wetlands areas in the East Dongting Lake in the past 20 years.

Polypore diversity in main natural larch forests in China.

WU Bin, WEI Yu-lian

2013, 24(11):  3237-3242. 

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Larch is the important coniferous species in Northern China. Many polypore species are growing on the fallen trunks of natural larch forests, which can decompose the cellulose, semi cellulose, and lignin of the fallen trunks, and promote the matter cycling and maintain the carbon balance in forest ecosystem, playing a key ecological function in forest ecosystem. Aiming at the polypore species on the 5 main larch forest species in China, this paper analyzed the species composition and distribution characteristics of polypore, and compared the polypore species diversity on different kinds of larch in China. A total of 107 polypore species were recorded, belonging to 43 genera in 11 families, among which, brown fungi accounted for 45.4% of the total collected in this study, and occupied about 50% of the whole brown fungi reported in China. 91.7% of the polypore grew on the decaying fallen trunk. Larix gmelini had more polypore species and individuals, as compared with the other 4 larch species. There was a high similarity in the polypore community composition on L. gmelini and L. olgensisi and on L. sibirica and L. griffithiana, which was in accordance with the natural distribution of related forests.

Effects of irrigation with mine wastewater on physiological characters and heavy metals accumulation of winter wheat.

MA Shou-chen1,2, MA Shou-tian2, SHAO Yun2, JIANG Li-na2, LI Chun-xi2

2013, 24(11):  3243-3248. 

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A pot experiment was conducted to study the effects of irrigation with mine wastewater on the physiological characters and heavy metals accumulation of winter wheat. Three treatments were installed, i.e., irrigation with coalwashing wastewater (T₁), irrigation with coalwashing wastewater after its precipitation (T₂), and irrigation with coal gangue leacheate (T₃), taking the well water irrigation as the control (CK). The plants were irrigated with mine wastewater after the turning green stage. Irrigation with mine wastewater had negative effects on the winter wheat growth and grain yield. At anthesis stage, the leaf area, dry mass per stem, root activity, and net photosynthetic rate of winter wheat in treatments T₁, T₂, and T₃ were significantly lower than those in CK (P＜0.05), the plant height and leaf chlorophyll content in T₃ decreased significantly (P＜0.05), and the grain yield in T₁, T₂ and T₃ was decreased by 15.4%, 9.8%, and 17.8%, respectively. In addition, the heavy metals (Cr, Pb, Cu and Zn) contents in the grain of winter wheat under mine wastewater irrigation were significantly higher than those in CK, suggesting that the irrigation with mine wastewater could result in the heavy metals accumulation in wheat grain.

Nutrient spatiotemporal distribution and eutrophication process in subsidence waters of Huainan and Huaibei mining areas, China.

QU Xi-jie1, YI Qi-tao1, HU You-biao1, YAN Jia-ping2, YU Huai-jun3, DONG Xiang-lin3

2013, 24(11):  3249-3258. 

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A total of eight mining subsidence waters, including five sites in Huainan “Panxie” Mining Areas (PXS-1, PXS-2, PXS-3, PXS-4, and PXS-5) and three sites in Huaibei “ZhuYang zhuang” Mining Areas (HBDH, HBZH, HBNH), were selected to study the nutrient temporal and spatial distribution and trophic states. Among the sites, three sites (PXS-1, PXS-3, and HBDH) showed higher nutrient level and could be classified into moderate eutrophication, whereas the other five were in moderate nutrient level and mild eutrophication. Overall, the nutrient level of Huainan mining subsidence waters was higher than that of Huaibei mining subsidence waters. All the test samples in the two mining areas had a higher ratio of nitrogen to phosphorus (N:P), being  25-117 in Huainan and 17-157 in Huaibei, and with a seasonal variety, the lowest in growth season. The dissolved inorganic phosphorus (DIP) in total phosphorous (TP) occupied a small percentage, being averagely 15.4% and 18.4% in Huainan and Huaibei mining areas, respectively. Nitrate was the main specie of dissolved inorganic nitrogen (DIN), with the ratio of nitrate to DIN being 74% and 89% in Huainan and Huaibei mining areas, respectively. Relative to the waters age, human activities could be one of the main factors responsible for the high nutrient level and the faster eutrophication process of these waters.

Spatiotemporal variation and related affecting factors of Gloiopeltis furcata biomass and length around Xiaoheishan Island, Shandong of China.

LIU Hong-liang, TANG Yong-zheng, YU Yong-qiang, LI Xue-meng, ZHANG Quan-sheng

2013, 24(11):  3259-3264. 

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Gloiopeltis furcata, an important economic red macroalga, has been severely depleted due to human disturbances. Taking the natural G. furcata populations around the Xiaoheishan Island of Shandong, China as test objects, this paper studied the spatiotemporal variation pattern of their biomass and length and related affecting factors. The twoway ANCOVA showed that at island scale, both the subbottom and the Baardseth index had significant effects on the G. furcata biomass and length. The steady subbottom and the high Baardseth index were beneficial to the G. furcata growth. At microhabitat scale, wave action and tidal level had significant effects on the G. furcata biomass and length. Wave wash and moderate tidal level promoted the G. furcata growth. The oneway repeated measurements ANOVA showed there existed seasonal variation of G. furcat biomass and length. The optimal growth period of G. furcata was from March to April, with the peak values of biomass and length appeared in late spring and early summer.

Optimal feeding strategy for juvenile Hucho taimen.

GUO Wen-xue, YIN Jia-sheng, ZHANG Yong-quan, TONG Guang-xiang, BAI Qing-li

2013, 24(11):  3265-3272. 

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Three experiments including starvation and re-feeding, starvation and re-feeding recovery, and feeding frequency per day were conducted to approach the optimal feeding strategy for the growth and survival of juvenile Hucho taimen. In the experiment of starvation and re-feeding, all groups of restricted feeding showed non-compensatory growth. However, in the experiment of starvation and re-feeding recovery, different degrees of compensatory growth appeared in different starving groups, among which, the half a day starvation and half a day feeding group (S_1/2) had a weight increment approximately the same as the control, and showed completely compensatory growth, indicating that the S_1/2 could be a useful feeding strategy for the juvenile H. taimen at its early growth stage with the body mass from 0 to 2 g and at the water temperature from 9 to 15.3 ℃. In feeding frequency experiment, the group T₃ (three meals per day) had the highest body length, body mass, specific growth rate, and relatively high food conversion ratio, indicating that three meals a day could be more effective for improving the growth performance of juvenile H. taimen at its late stage with the body mass from 2 to 21 g and at the water temperature from 8.8 to 15.5 ℃.

Effects of venom from Sclerodermus sichuanensis Xiao onpupaof Tenebrio molitor.

ZHUO Zhi-hang1, YANG Wei1, QIN Huan1, YANG Chun-ping1, YANG Hua1, XU Dan-ping2

2013, 24(11):  3273-3279. 

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To explore the regulatory mechanisms of parasitism of Sclerodermus sichuanensis on Tenebrio molitor, the methods of natural parasitism and venom injection were adopted to investigate the effects of the venom from S. sichuanensis on the pupa of T. molitor in the parasitic process. Under venom injection, the paralytic degree of the pupa had a positive correlation with the concentration of injected venom, and the number of recovered pupa had a negative correlation with the injected venom concentration. The T. molitor pupa was in slight and reversible paralysis when injected with 0.01 VRE (venom reservoir equivalent) of venom, and in nonreversible and complete paralysis when 0.2 VRE was injected. The pupa died massively and appeared a wide range of melanization when injected with soil bacterial suspension alone, but the melanization delayed and the mortality declined significantly when the mixed liquor of bacterium and venom was injected. The bacteriostasis of the venom on Staphylococcus aureus was significantly stronger than that on Escherichia coli. Within a definite range of temperature, the paralytic activity decreased significantly with increasing temperature, the bacteriostasis on S. aureus increased significantly, while that on E. coli was opposite. This study showed that the venom from S. sichuanensis had the effects of paralysis, bacteriostasis, inhibiting exuviations, and delaying melanization.

Estrogens determination of livestock dung based on UE-SPE-HPLC/FLD.

FU Yin-jie1,2, LING Wan-ting1, DONG Chang-xun2, LIU Juan1, GAO Yan-zheng1， PAN Yu-lan1

2013, 24(11):  3280-3288. 

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A method for detecting the estrogens estriol, 17β-estradiol, ethinyl estradiol, and bisphenol A in livestock dung was established by the combination of ultrasonic extraction (UE), solid phase extraction (SPE) purification, and high performance liquid chromatography (HPLC) with fluorescence detector (FLD). The dung samples were extracted with ethyl acetate ultrasonication for 30 min, and purified with C₁₈ solid phase extraction column and related solvents. The test four estrogens in the dung samples were isolated with Inertsil ODS-SP-C₁₈ reversedphase columns (150 mm×4.6 mm, 5 μm), and the isolated estrogens were detected with HPLC/FLD. The mobile phase of HPLC for the detection was methanol/acetonitrile/water (volume ratio of 20:30:50), with a flow rate of 0.8 mL·min^-1. The excitation and emission wavelengths of FLD were 280 and 310 nm, respectively, the HPLC column temperature was 40 ℃, and the injection volume was 20 μL. Good linearity (correlation coefficient greater than 0.9995) was observed by the HPLC/FLD detection when the test four estrogens concentrations were in the range of 1.00-1000.00 μg·L^-1. The detection limit of estriol, bisphenol A, 17β-estradiol, and ethinyl estradiol was 3.35, 5.01, 2.13, and 1.12 μg·kg^-1, respectively. When the added estrogens concentrations of pig, cow, and chicken dung samples were 0.05, 0.40, and, 1.00 μg·kg^-1, the average recovery of the four estrogens was 75.1%-91.1%, 78.4%-117.0%, and 78.6%-97.8%, respectively, with the relatively standard deviations (RSD, n=6) all less than 6%. By adopting the established SPEHPLC/FLD method to detect the estrogens in real pig, cow, and chicken dung samples from parts of the largescale livestock raising farms in Nanjing of East China, the detection reproducibility was high, and the detection limit was low, being available and effective for the detection of the estrogens in livestock dung.

Isolation and characterization of petroleum catabolic broadhostrange plasmids from ShenFu wastewater irrigation zone.

WANG Ya-fei1,2, LI Hui1, LI Xiao-bin1,2

2013, 24(11):  3289-3299. 

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Based on triparental mating, we isolated a total of eight broad host range （BHR） petroleum hydrocarbon catabolic plasmids from the soils, sediments, and wastewater samples in the ShenFu irrigation zone. The antibiotic resistance of the plasmids was tested, and then, the plasmids were transferred to Escherichia coli EC100. The plasmids carrying no antibiotic resistance were tagged by miniTn5 transposon consisting of antibiotic resistant genes. The PCRbased incompatibility test revealed that the pS3-2C and pS4-6G belonged to Inc P group, the pS3-2G, pW22-3G, and pA15-7G belonged to Inc N group, the pS7-2G was identified as Inc W plasmid, and the pA23-1G and pA10-1C were placed into Inc Q group. By adopting the reported PCR amplification methods of petroleum hydrocarbondegrading catabolic genes, the petroleumdegrading capability of these BHR plasmids were preliminarily analyzed. The plasmids pS3-2G, pS7-2G, pA23-1G, pW22-3G, and pA10-1C carried aromatic ring- hydroxylating dioxygenase gene phdA and toluene monooxygenase gene touA; the plasmid pA15-7G carried  touA and toluene dioxygenase gene tod; the plasmid pS3-2C carried ben, phdA, and tod; whereas the pS4-6G only carried ben. The host range test showed that all the isolated plasmids except pS3-2C could be transferred and maintained stably in the representative strains Agrobacterium tumefaciens C58, Cupriavidus necator JMP228, and E. coli EC100 of the α-, β-, and γ-Proteobacteria, respectively.

Effects of environmental factors on litter decomposition in arid and semi-arid regions: A review.

WANG Xin-yuan1,2, ZHAO Xue-yong1, LI Yu-lin1, LIAN Jie1,2, QU Hao1, YUE Xiang-fei1,2

2013, 24(11):  3300-3310. 

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Litter decomposition is one of the important biochemical processes in arid and semi-arid regions, and a key component of regional nutrient turnover and carbon cycling, which is mainly affected by climate, litter quality, and decomposer community. In order to deeply understand the relationships between litter decomposition and environmental factors in arid and semiarid regions, this paper summarized the research progress in the effects of abiotic factors (soil temperature, precipitation, and ultraviolet-B radiation) and biotic factors (litter quality, soil microbial and animal composition and community structure) on the litter decomposition in these regions. Among the factors, precipitation and ultraviolet-B radiation are considered to be the main limiting factors of litter decomposition. In arid and semi-arid regions, precipitation can significantly increase the litter decomposition rate in a short term, while the photo-degradation induced by ultraviolet-B radiation, due to the strong and long-term radiation, can increase the decomposition rate of terrestrial litter. Litter quality, soil microbial and animal composition and community structure are mainly affected by the type of ecosystems in a long term. However, the affecting mechanisms of these environmental factors on litter decomposition are still not very clear. It was suggested that the future litter ecological research should be paid more attention to the interaction of environmental factors under climate change, the variations of litter decomposition at different spatial scales, and the establishment of litter decomposition models in relation to the synergistic interactions of multiple factors.

Effects of biochar on microbial ecology in agriculture soil: A review.

DING Yan-li, LIU Jie, WANG Ying-ying

2013, 24(11):  3311-3317. 

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Biochar, as a new type of soil amendment, has been obtained considerable attention in the research field of environmental sciences worldwide. The studies on the effects of biochar in improving soil physical and chemical properties started quite earlier, and already covered the field of soil microbial ecology. However, most of the studies considered the soil physical and chemical properties and the microbial ecology separately, with less consideration of their interactions. This paper summarized and analyzed the interrelationships between the changes of soil physical and chemical properties and of soil microbial community after the addition of biochar. Biochar can not only improve soil pH value, strengthen soil water-holding capacity, increase soil organic matter content, but also affect soil microbial community structure, and alter the abundance of soil bacteria and fungi. After the addition of biochar, the soil environment and soil microorganisms are interacted each other, and promote the improvement of soil microbial ecological system together. This review was to provide a novel perspective for the in-depth studies of the effects of biochar on soil microbial ecology, and to promote the researches on the beneficial effects of biochar to the environment from ecological aspect. The methods to improve the effectiveness of biochar application were discussed, and the potential applications of biochar in soil bioremediation were further analyzed.

Application of lysosomal detection in marine pollution monitoring: Research progress.

WENG You-zhu, FANG Yong-qiang, ZHANG Yu-sheng

2013, 24(11):  3318-3324. 

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Lysosome is an important organelle existing in eukaryotic cells. With the development of the study on the structure and function of lysosome in recent years, lysosome is considered as a target of toxic substances on subcellular level, and has been widely applied abroad in marine pollution monitoring. This paper summarized the biological characteristics of lysosomal marker enzyme, lysosomeautophagy system, and lysosomal membrane, and introduced the principles and methods of applying lysosomal detection in marine pollution monitoring. Bivalve shellfish digestive gland and fish liver are the most sensitive organs for lysosomal detection. By adopting the lysosomal detection techniques such as lysosomal membrane stability (LMS) test, neutral red retention time (NRRT) assay, morphological measurement (MM) of lysosome, immunohistochemical (Ih) assay of lysosomal marker enzyme, and electron microscopy (EM),  the status of marine pollution can be evaluated. It was suggested that the lysosome could be used as a biomarker for monitoring marine environmental pollution. The advantages and disadvantages of lysosomal detection and some problems worthy of attention were analyzed, and the application prospects of lysosomal detection were discussed.

Diversity of arbuscular mycorrhizal fungi in special habitats: A review.

LI Su-mei, WANG Yin-qiao, LIU Run-jin

2013, 24(11):  3325-3332. 

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Arbuscular mycorrhizal fungi (AMF) are one of the important components in ecosystems, which not only have the diversity in genetics, species composition, and function, but also have the diversity in distribution and habitat. AMF infect plant root, form mycorrhiza, and nourish as obligate biotroph symbiont, with strong ecological adaptability. They not only distribute in forest, prairie, and farm land, but also distribute in the special habitats with less plant species diversity, such as commercial greenhouse soil, salinealkali soil, mining pollution land, petroleum-contaminated land, pesticide-polluted soil, desert, dry land, wetland, marsh, plateau, volcanic, cooler, and arctic tundra, composing a unique community structure and playing an important irreplaceable role in the physiological and ecological functions. This paper summarized the species diversity and mycorrhizal morphological features of AMF in special habitats, aimed to provide essential information for the further studies on the AMF in these special habitats and extreme environments.