Table of Content

20 June 2009, Volume 20 Issue 06

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Articles

Spatial patterns of dominant tree species in sub-alpine Betula-Abies forest in West Sichuan of China.

MIAO Ning¹;LIU Shi-rong¹;SHI Zuo-min¹;YU Hong²;LIU Xing-liang³

2009, 20(06):  1263-1270 . 

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Based on the investigation in a 4 hm2 Betula-Abies forest plot in sub-alpine area in West Sichuan of China, and by using point pattern analysi s method in terms of O-ring statistics, the spatial patterns of dominant specie s Betula albo-sinensis and Abies faxoniana in different age classes in study ar ea were analyzed, and the intra- and inter-species associations between these age classes were studied. B. albo-sinensis had a unimodal distribution of i ts DBH frequency, indicating a declining population, while A. faxoniana had a reverse J-shaped pattern, showing an increasing population. All the big trees of B. albo-sinensis and A. faxoniana were spatially in random at all s cales, while the medium age and small trees were spatially clumped at small scal es and tended to be randomly or evenly distributed with increasing spatial scale . The maximum aggregation degree decreased with increasing age class. Spatial as sociation mainly occurred at small scales. A. faxoniana generally showed pos itive intra-specific association, while B. albo-sinensis generally showed negative intra-specific association. For the two populations, big and small tre es had no significant spatial association, but middle age trees had negative spa tial association. Negative inter-specific associations of the two populations w ere commonly found in different age classes. The larger the difference of age cl ass, the stronger the negative inter-specific association.

Stem radius growth of Picea meyeri and Larix principis-rupprechtii nearby the tree-line of Luya Mountain.

JIANG Yuan^1,2,3;YANG Yan-gang^1,2,3;DONG Man-yu^1,2,3;ZHANG Wen-tao^1,2,3;REN Fei-peng^1,2,3

2009, 20(06):  1271-1277 . 

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The stem radius growth (SRG) of six samples of Picea meyeri and fi ve samples of Larix principis-rupprechtii nearby the tree-line of Luya Mou ntain in North China was measured by the dendrometer in the summer phase from Ju ly 15 to August 7 and the autumn phase from September 5 to October 9, 2007, with the environmental factors measured simultaneously. In the summer phase, there w as no significant difference in the sensitivity of SRG to the environmental fact ors fluctuation between the two species; but in the relatively cold and dry autu mn phase, the SRG of P. meyeri was more sensitive to the fluctuation of envi ronmental factors. The accumulated SRG of the two species increased linearly in summer phase, but decreased first and kept stable then in autumn phase, with the growth increment of P. meyeri fluctuated more than that of L. principis- rupprechtii. The SRG of the two species correlated positively with hydrologica l factors and negatively with thermal factors, and the SRG of P. meyeri was strongly affected by air humidity and temperature, while that of L. principis -rupprechtii was mainly affected by soil moisture.

Root decomposition characteristics of Castanopsis carlesii stand in Wanmulin Natural Reserve of Fujian Province.

LIN Cheng-fang^1,2;YANG Yu-sheng²;GUO Jian-fen²;CHEN Guang-shui²;YUAN Yi-ding²

2009, 20(06):  1278-1284 . 

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By using litter-bag method, the root decomposition characteristics of Castanopsis carlesii stand in Jian’ou Wanmulin Natural Reserve of Fujian P rovince were studied over two years. Three classes of roots, i.e., 0〖KG-*2〗-〖 KG-*7〗1 mm, 1〖KG-*2〗-〖KG-*7〗2 mm, and 2〖KG-*2〗-〖KG-*7〗4 mm in diameter, were tested. During the 2-year period of decomposition, all classes roots show ed a bi-phase pattern, being decomposed faster in prophase and slower in anapha se. The leaching loss of extractable substances in roots made root decomposition faster in prophase, while the increase of the acid-insoluble substances conce ntration in roots restrained the decomposition in anaphase. In the first year, t he decomposition rate of all classes roots was controlled by the initial concent rations of their extractive substances and N; while in the second year, the deco mposition rate was controlled by the initial C/N and the initial concentrations of acid-insoluble substances, N and P of the roots. During decomposition, all c lasses roots showed an increasing N concentration and a decreasing P concentrati on, and the N showed an enrichment-release pattern, while the P showed a direct release pattern.

Carbon dynamics of broad-leaved Korean pine forest ecosystem in Changbai Mountains and its responses to climate change.

TANG Feng-de^1,2;HAN Shi-jie²;ZHANG Jun-hui²

2009, 20(06):  1285-1292 . 

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By using process model Sim-CYCLE based on dry matter production theory, this pa per estimated the gross primary productivity (GPP), net primary productivity (NP P), net ecosystem productivity (NEP), ecosystem carbon storage (WE), total plant carbon storage (WP), and total soil carbon storage (WS) of broad-leave d Korean pine forest ecosystem in Changbai Mountains from 1982 to 2003, and anal yzed the variations of these indices under present climate condition and carbon equilibrium state as well as the responses of these indices to climate change sc enarios in the future. Under present climate condition, the estimated GPP, NPP, and NEP were 149, 87, and 27 Mg C·hm-2·a-1, being 28 Mg C ·hm-2·a-1 less and 14 and 02 Mg C·hm-2·a-1 highe r than the measured values, respectively. The NEP in June〖KG-*3〗-〖KG-*7〗August occupied more than 90% of the annual NEP, and the maximum monthly NEP appeared in July (123 Mg C·hm-2·month-1). The estimated WE, WP, and WS were 5508, 183 8, and 3670 Mg C·hm-2, respectively, very close to the me asured values. From present climate condition to carbon equilibrium state, the e stimated carbon storages of the forest ecosystem increased to some extent, with the GPP and NPP being 177 and 73 Mg C·hm-2·a-1, respectively, suggesting that the role of the forest ecosystem as a carbon “sink” declined g radually with the increase of carbon storage. A 2 ℃-increment of air temperat ure did not benefit the increase of GPP, NPP and NEP, while doubling CO2 conce ntration was in adverse. The effects of the combination of doubling CO2 concen tration and 2 ℃-increment of air temperature on the GPP, NPP, and NEP were si milar to those of doubling CO2 concentration. The climate change scenario in t he future had the same effects both on the carbon storage and on the productivit y of the forest ecosystem, which was mainly correlated to the effects of primary productivity on the carbon storage.

Characteristics of soil seed banks in logging gaps of forests at different succession stages in Changbai Mountains.

ZHANG Zhi-ting¹;SONG Xin-zhang²;XIAO Wen-fa³;GAO Bao-jia¹;GUO Zhong-ling⁴

2009, 20(06):  1293-1298 . 

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An investigation was made on the soil seed banks in the logging gaps o f Populus davidiana-Betula platyphylla secondary forest, secondary broad-l eaved forest, and broad-leaved Korean pine mixed forest at their different succ ession stages in Changbai Mountains. Among the test forests, secondary broad-le aved forest had the highest individual density (652 ind·m-2) in its soil seed bank. With the succession of forest community, the diversity and uniformity of soil seed bank increased, but the dominance decreased. The seed density of c limax species such as Pinus koraiensis, Abies nephrolepis, and Acer mono increased, whereas that of Maackia amurensis and Fraxinus mandshurica d ecreased. Moreover, the similarity in species composition between soil seed bank and the seedlings within logging gaps became higher. The individual density and similarity between soil seed bank and the seedlings in non-logging gaps were s imilar to those in logging gaps. All of these indicated that soil seed bank prov ided rich seed resources for forest recovery and succession, and the influence o f soil seed bank on seedlings regeneration increased with the succession.

Effects of elevated CO₂ concentration on the growth of submerged macrophyte Potamogeton malaianus in Taihu Lake.

DENG Jian-cai₁;ZHAI Shui-jing_1,2;CHEN Qiao_1,2

2009, 20(06):  1299-1304 . 

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An outdoor culture experiment was conducted to study the growth and nutrient con tents of submerged macrophyte Potamogeton malaianus in Taihu Lake unde r different CO2 concentrations. As affected by elevated CO2 concentration (1 000 μmol·mol-1), the biomass per plant increased by 443% (P<001) , but the shoot biomass decreased by 55% (P<0.05). The N content in root a nd leaf decreased by 181% (P<005) and 64% (P<005), respectively, but that in stem was less affected (P>005). The P content in root, shoot, and leaf increased by 222% (P<005), 266% (P>005) and 388% ( P<005), soluble sugar content increased by 273%, 183% and 375% (P< 005), and total C content increased by 46%, 53% and 20%, respectively. E levated CO2 concentration decreased the N and P concentrations in w ater body by 79% and 51% (P<005), respectively, but had less effects o n the N and P contents in sediment. It was suggested that elevated CO2 concent ration had definite effects on the growth and habitat of submerged macrophytes.

Effects of plant functional groups removal on the soil carbon, nitrogen pools in a Leymus chinensis community of typical steppe in Inner Mongolia.

SHA Qiong^1,2;HUANG Jian-hui¹;BAI Yong-fei¹;HAN Xing-guo¹

2009, 20(06):  1305-1309 . 

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A field plant functional groups (PFGs) removal experiment was conducted in 2005 〖KG-*2〗-〖KG-*7〗2007 to study the effects of plant diversity in a Le ymus chinensis community of typical steppe in Inner Mongolia on the topsoil (0〖KG-*2〗-〖KG-*7〗10 cm) carbon (C) and nitrogen (N) pools. In the three succ essive years, the topsoil total C and N contents had a slight change (<15%). They changed little in 2005, but were significantly higher in 2006 than i n 2007 (P<005). The topsoil NH4+-N content had a greater inter-annu al change, being 80% higher in 2006 than in 2007, while the NO3--N content had less significant change (P>005). There was a positive linear relation ship (P<005) between the number of removed PFGs and the content of soil NO3--N, which meant that the decrease of plant diversity increased so il NO3--N content, and consequently, led to a possible soil nitrogen loss through leaching.

Difference and its formation cause in soil organic carbon accumulation capability of two typical tidal wetlands at Dongtan of Chongming Island in Shanghai.

LI Yan-li¹;XIAO Chun-ling²;WANG Lei¹;ZHANG Wen-quan¹;ZHANG Shi-ping¹;WANG Hong-li¹;FU Xiao-hua¹;LE Yi-quan¹

2009, 20(06):  1310-1316 . 

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Through the analyses of soil organic carbon content and vegetation inp ut, this paper studied the difference in soil organic carbon accumulation capabi lity of two typical tidal wetlands, one (A) was on the erosion bank with Phragmites communis and sandy loam soil at southeast Dongtan in Shanghai, and the other (B) was on the alluvial bank with P. communis, Spartina alterniflora, and c lay soil at northeast Dongtan of Chongming Island. The main formation causes of the difference were analyzed based on the determinations of soil microbial activ ities and physical-chemical properties. In A, the average soil total organic ca rbon content was 4610% (P<005) of that in B, while the annual abovegro und vegetation dry mass was only 916% lower than that in B, illustrating that the soil organic carbon output was higher in A than in B. The total count of soi l bacteria and the activities of soil catalase and invertase in A were 3.82 time s (P<005), 4681% (P<005), and 3433% (P<005) higher than th ose in B, respectively, and the soil microbial respiration in A was also higher than that in B, which indicated that the stronger soil microbial C- metabolic a ctivity in A was the main cause inducing the lower soil organic carbon accumulat ion capability. The sandy loam soil in A had higher porosity and lower salinity and moisture, being favorable to the growth of soil microbes and the decompositi on of soil organic carbon, while the clay soil in B had higher salinity and mois ture but lower microbial activity, leading to the weaker soil organic carbon dec omposition and higher organic carbon accumulation.

Seasonal dynamics of nitrogen- and phosphorus absorption efficiency of wetland plants in Minjiang River estuary.

ZHANG Wen-long¹;ZENG Cong-sheng^1,2,3,4;ZHANG Lin-hai^1,2;WANG Wei-qi^1,2;LIN Yan¹;AI Jin-quan¹

2009, 20(06):  1317-1322 . 

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Taking the native Phragmites australis and invasive Spartina alterniflora in Minjiang River estuary as test objectives, this paper studied the seasonal dynamics of their biomass and nitrogen- and phosphorus absorption efficiency. A typical single-peak curve was presented for the seasonal dynamics of aboveground biomass and nitrogen- and phosphorus absorption efficiency of the two species. P. australis had the maximum aboveground biomass (219533 g·m-2) in summer, while S. alterniflora had it (367002 g·m-2) in autumn. The total nitrogen (TN) and total phosphorus (TP) contents of P australis reached the peak (2106 g·m-2 of TN and 112 g·m-2 of TP) in summer and in autumn, respectively, while those of S. alterniflora all reached the peak (2676 g·m-2 of TN and 323 g·m-2 of TP) in autumn. Both of the two species had a higher absorption efficiency in TN than in TP (P<001), and S. alterniflora had a significantly higher absorption efficiency of TN and TP than P. australis (P<0.05). To some extent, the N/P, C/N, and C/P ratios of plants could indicate the nitrogen- and phosphorus absorption efficiency of the plants.

Characteristics of soil seed banks in different water level areas after returning farmland into lake in Qingshanyuan of Dongting Lake.

HOU Zhi-yong^1,2;XIE Yong-hong¹;YU Xiao-ying²;LI Feng¹

2009, 20(06):  1323-1328 . 

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To study the composition and distribution of soil seed bank in the areas after returning farmland into lake is of significance in evaluating the ecological restoration effect of damaged wetlands. In this paper, the composition and diversity of seed bank in soil profile (0〖KG-*2〗-〖KG-*7〗2, 2〖KG-*2〗-〖KG-*7〗5, and 5〖KG-*2〗-〖KG-*7〗10 cm) and their relationships with above-ground vegetation in different water level areas in Qingshanyuan, a typical region after returning farmland into lake in Dongting Lake, were investigated. A V- type variation pattern was observed in the seed density and species richness of soil seed bank and in the similarity coefficient of soil seed bank and above-ground vegetation along a gradient of low-medium-high water level. As for the seed density, it was the highest (36943±5207 seeds·m-2) in frequently flooded area, followed by in heavily flooded area (30572±5329 seeds·m-2), and in incidentally flooded area (18618±6977 seeds·m-2); for the similarity coefficient, it was also in the order of frequently flooded area (076)> heavily flooded area (053)> incidentally flooded area (041). The seed density, species diversity, and species richness of soil seed bank decreased along soil profile, but the decrements differed in different water level areas. The regular variation patterns of the seed density and species richness of soil seed bank and of the similarity coefficient of soil seed bank and above-ground vegetation along the water level gradient were closely related to the water-level fluctuation and the life-form composition of the vegetations in study area.

Spatial heterogeneity of soil organic matter and its response to disturbance in karst peak cluster depressions.

OUYANG Zi-wen^1,2,3;PENG Wan-xia^1,2,3;SONG Tong-qing^1,2;ZENG Fu-ping^1,2;WANG Ke-lin^1,2;GUAN Xin³;WU Hai-yong^1,2,4

2009, 20(06):  1329-1336 . 

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By using geostatistic methods, this paper studied the spatial variation and dist ribution of soil organic matter as well as its ecological processes and related mechanisms in four typical disturbed areas (cropland, man-made forest, secondary forest, and primary forest) of karst peak cluster depressions in nort hwest Guangxi of China. Eighty soil samples (0〖KG-*2〗-〖KG-*7〗20 cm) were coll ected from an aligned grid of 10 m×10 m for the analysis of soil organic matter . The soil organic matter content increased significantly (P<005) with the decrease of disturbance and the vegetation succession from crop to man-made fo rest to secondary forest to primary forest. Soil organic matter content had good spatial autocorrelation in all of the four typical disturbed areas, but its spa tial heterogeneity differed. Gaussian model fitted best to the semivariance fun ctions of soil organic matter content in the study areas except secondary forest area where exponential model fitted well. In cropland area, the spatial autocor relation of soil organic matter was at medium level, with the C0/(C0 +C) being 265%; while in the other three areas, the spatial autocorrelatio n was at high level, with the C0/(C0+C) being 90%〖KG-*2〗-〖K G-*7〗226%. The range and scale of the spatial autocorrelation of soil orga nic matter in cropland and man-made forest areas were larger than those in the other two areas, possibly due to the strong human disturbance and the homogeneit y of low energy. The range of the spatial autocorrelation of soil organic matter in primary forest area was large due to the high vegetation coverage, while tha t in secondary forest area was the lowest due to the diverse vegetation communit ies and their uneven distribution. The low fractal value (D) of semivariance fu nctions of soil organic matter in man-made forest and primary forest areas sugg ested that a strong spatial dependence existed, while the high D in cropland and secondary forest areas suggested a great random variance of spatial distributio n of soil organic matter occurred. The spatial pattern of soil organic matter pr esented a unimodal distribution in cropland and man-made forest areas, a concav e distribution in secondary forest area, and a gibbous distribution in primary fo rest area. To reduce human disturbance would be helpful to the soil quality impr ovement, rapid vegetation restoration, and ecological reconstruction of karst de generative ecosystems.

Regulation effect of water storage in deeper soil layers on root physiological characteristics and leaf photosynthetic traits of cotton with drip irrigation under mulch.

LUO Hong-hai^1，2;ZHANG Hong-zhi^1，2;DU Ming-wei^1，2;HUANG Jian-jun^1，2;ZHANG Ya-li^1，2;ZHANG Wang-feng^1，2

2009, 20(06):  1337-1345 . 

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A soil column culture experiment was conducted under the ecological an d climatic conditions of Xinjiang to study the effects of water storage in deepe r (>60 cm) soil layers on the root physiological characteristics and leaf photo synthetic traits of cotton variety Xinluzao 13. Two treatments were installed, i.e., well-watered and no watering. The moisture content in plough layer was controlled at 70%±5% and 55%±5% of field capacity by drip irrigation under mulch d uring growth season. It was shown that the water storage in deeper soil layers e nhanced the SOD activity and the vigor of cotton root, and increased the water u se efficiency of plant as well as the leaf water potential, chlorophyll content, and net photosynthesis rate, which finally led to a higher yield of seed cotton and higher water use efficiency. Under well-watered condition and when the moi sture content in plough layer was maintained at 55% of field capacity, the senes cence of roots in middle and lower soil layers was slower, and the higher root v igor compensated the negative effects of impaired photosynthesis caused by water deficit to some extent. The yield of seed cotton was lower when the moisture co ntent in plough layer was maintained at 55% of field capacity than at 70% of fie ld capacity, but no significant difference was observed in the water use efficie ncy. Our results emphasized the importance of pre-sowing irrigation in winter or in spring to increase the water storage of deeper soil layers. In addition, pro per cultivation practices and less frequent drip irrigation (longer intervals be tween successive rounds of irrigation) were also essential for conserving irriga tion water and achieving higher yield.

Coupling effect of water and nitrogen for cotton under different furrow irrigation patterns.

LI Pei-ling;ZHANG Fu-cang;JIA Yun-gang

2009, 20(06):  1346-1354 . 

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A field plot experiment with general rotation design was conducted to study the coupling effect of water amount and nitrogen (N) application rate for cotton under alternative furrow irrigation (AFI), conventional furrow irrigation (CFI), and fixed separate furrow irrigation (FFI). When the water amount was 37 52〖KG-*2〗-〖KG-*7〗16000 mm and N application rate was 562〖KG-*2〗-〖KG -*7〗952 kg N·hm-2, cotton yield had significant positive correlations with them; when the two factors were in the ranges of 16000〖KG-*2〗-〖KG-*7〗21848 mm and 952〖KG-*2〗-〖KG-* 7〗1342 kg N·hm-2, respe ctively, no significant change was observed in the cotton yield. Within the test ranges of water amount and N application rate, cotton yield had no significant difference between AFI and CFI, but was 915% higher under CFI than under FFI. The water use efficiency (WUE) of cotton was significantly negatively correl ated with the water amount 3752〖KG-*2〗-〖KG-*7〗16000 mm and positively co rrelated with the N application rate 562〖KG-*2〗-〖KG-*7〗1228 kg N·hm-2, but had no s ignificant change when the water amount was 16000〖KG-*2〗-〖KG-*7〗21848 mm and N application rate was 1228〖KG-*2〗-〖KG-*7〗1 342 kg N·hm-2. Within the test ranges of water amount and N application rate, the WUE had no significant difference between CFI and AFI, but was 901% higher under CFI than under FFI. The nitrogen use efficiency (NUE) of cot ton had significant positive correlation with the water amount 3752〖KG-*2〗- 〖KG-*7〗16000 mm but significant negative correlation with the N application rate 562〖KG-*2〗 -〖KG-*7〗1342 k g N·hm-2, and had no significant difference between AFI and CFI but was 6 34% was lower under FFI than under CFI. Appropriate measures for high-efficie ntly using water and nitrogen resources under different furrow irrigation patter ns were put forward to optimize cotton yield, WUE and NUE.

Effects of tillage pattern on the flag leaf senescence and grain yield of winter wheat under dry farming.

HUANG Ming1;WU Jin-zhi1;LI You-jun¹;YAO Yu-qing²;ZHANG Can-jun²;CAI Dian-xiong³;JIN Ke³

2009, 20(06):  1355-1361 . 

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A field experiment was conducted to study the effects of different tillage patterns, i.e., deep plowing once, no-tillage, subsoiling, and conventional tillage, on the flag leaf senescence and grain yield of winter wheat, as well as the soil moisture and nutrient status under dry farming. No-tillage and subsoiling increased the SOD and POD activities and the chlorophyll and soluble protein contents, decreased the MDA and O〖SX（B-*3〗-〖〗·〖SX）〗2 contents, and postponed the senescence of flag leaf. Under non-tillage and subsoiling, the moisture content in 0〖KG-*2〗-〖KG-*7〗40 cm soil layer at anthesis and grain-filling stages was decreased by 413% and 623% and by 550% and 927%, respectively, and the contents of alkali-hydrolysable N, available P, and available K in this soil layer also increased significantly, compared with those under conventional tillage. Deep plowing once decreased the moisture content and increased the nutrients contents in 0〖KG-*2〗-〖KG-*7〗40 cm soil layer, but the decrement and increment were not significant. The post-anthesis biomass, post-anthesis dry matter translocation rate, and grain yield under no-tillage and subsoiling were 434% and 476%, 1556% and 1351%, and 1022% and 926% higher than those under conventional tillage, respectively. It could be concluded that no-tillage and subsoiling provided better soil conditions for the post-anthesis growth of winter wheat, under which, the flag leaf senescence postponed, post-anthesis dry matter accumulation and translocation accelerated, and grain yield increased significantly, being the feasible tillage practices in dry farming winter wheat areas.

Characteristics of N forms and N-transforming bacteria in paddy soil under different tillage patterns.

GU Ming-hua¹;OU Hui-ping¹;LIU Xi-hui²;HUANG Jing¹;LI Xiao-feng¹;LI Liu-xia¹;SHEN Fang-ke¹;JIANG Li-geng¹

2009, 20(06):  1362-1368 . 

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Paddy soil samples were collected in layers (0〖KG-*2〗-〖KG-*7〗5, 5〖KG-*2〗- 〖KG-*7〗12, and 12〖KG-*2〗-〖KG-*7〗20 cm) during rice growth period to invest igate the characteristics of the N forms and N-transforming bacteria in the soi l profile under different tillage patterns (no-tillage with straw returning, NT S; conventional tillage with straw returning, CTS; no-tillage, NT; and conventi onal tillage, CT). In the whole rice growth period, ammonifying bacteria in 0〖K G-*2〗-〖KG-*7〗5 cm soil layer had the highest number under NTS, and nitrosobac teria in 0〖KG-*2〗-〖KG-*7〗5 cm and 5〖KG-*2〗-〖KG-*7〗12 cm soil layers were more abundant but in 12〖KG-*2〗-〖KG-*7〗20 cm soil layer were lesser under CT than under NT. Nitrosobacteria and denitrobacteria in 0〖KG-*2〗-〖KG-*7〗20 cm soil layer were lesser under NTS than under CTS. At elongating and ripening sta ges, anaerobic N-fixing bacteria in 0〖KG-*2〗-〖KG-*7〗5 cm soil layer were mo re abundant under NT than under CT. In the whole rice growth period, the alkali -hydrolyzable N and total N contents in 0〖KG-*2〗-〖KG-*7〗5 cm soil layer wer e significantly higher but in 5〖KG-*2〗-〖KG-*7〗12 cm and 12〖KG-*2〗-〖KG-*7 〗20 cm soil layers were lower under NT than under CT, and the NH4+-N and N O3--N contents in 0〖KG-*2〗-〖KG-*7〗20 cm soil layer were higher under NT S but in 12〖KG-*2〗-〖KG-*7〗20 cm soil layer had no significant differences be tween NT and CT. Correlation analysis and multiple polynomial regression analysi s further revealed that there were significant relationships between soil NH4 +-N and soil ammonifying bacteria, nitrosobacteria and denitrobacteria, and b etween soil alkali-hydrolyzable N and soil anaerobic N-fixing bacteria. Among the test tillage patterns, NTS could be the more desirable one for the N supply and fertility maintenance of paddy soil.

Dynamic simulation of ammonia- and nitrate N leakage from paddy field under different N supply.

LI Jin-wen¹;ZHONG Sheng²;WANG Mi¹;YANG Jing-ping²;XU Wei²

2009, 20(06):  1369-1374 . 

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By using self-designed lysimeters, the dynamic changes of ammonia- and nitrate N leakage from the plowpan of paddy field under different N supply were studied , aimed to understand the N leakage loss from paddy field during rice growth per iod. A dynamic model was built to simulate the N translocation and transf ormation in rice plant, soil, and water by Vensim software. The data from the field experiment with N fertilization rates of 0, 75, 150, 225, 300, and 375 kg·hm-2 in Yuhan g district, Hangzhou City in 2003 were used for calibrating the model, and the data from the field experiment in 2007 were utilized for validating the model. The simul ated N concentrations in the leakage fitted well with the observed data, suggest ing that the simulated results were reliable and the model was applicable.

Individual and interactive effects of aluminum, selenium, silicon and phosphorus on rice seedlings growth.

PANG Zhen-wu;SHI Rui-hong;XIE Guo-sheng;LIU Tie-mei;KE Wen-feng;CAI Ming-li

2009, 20(06):  1375-1382 . 

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By using quadratic orthogonal rotation combinatorial design, and taking aluminum (Al), selenium (Se), silicon (Si), and phosphorus (P) as test factors, the regression models of test factors and the survival rate (SR), shoot mass per hundred plants (SMHP), root mass per one hundred plant seedlings (RMHP), and proline contents (PC) of rice seedlings were established, with the individual and interactive effects of the factors analyzed. The individual effects of test factors on the SR, SMHP, RMHP, and PC of rice seedlings decreased in the order of Al>P>Se>Si. Al showed negative effect, while Se, Si, and P showed positive effect. There were no significant interactive effects between the factors, except between Al and Si. Simulated optimization test showed that rice seedlings could grow better in an Al-containing solution when the Al was within the range of 0587〖KG-*2〗-〖KG-*7〗0913 mmol·L-1, Se was of 0478〖KG-*2〗-〖KG-*7〗0564 mg·L-1, Si was of 0613〖KG-*2〗-〖KG-*7〗1069 mmol·L-1, and P was of 2252 〖KG-*2〗-〖KG-*7〗2657 mmol·L-1.

Adsorption-desorption and competitive adsorption of arsenic and phosphorus in purple soil.

ZOU Qiang;LIU Fang;YANG Jian-hong

2009, 20(06):  1383-1389 . 

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A batch incubation test was conducted to study the characteristics of arsenic (A s) and phosphorous (P) adsorption-desorption as well as the effects of the comp etitive adsorption of the two elements on their translocation and activation in three kinds of purple soil, the typical soil in Three Gorges Area. In the test a cid, neutral, and calcareous purple soils, As and P adsorption-desorption had t he similar characteristics, with their isothermal adsorption conformed to Langmu ir and Freundlich equations. The maximum adsorption of As in the acid, neutral, and calcareous purple soils was 14286, 12500, and 11111 mg·kg-1, an d that of P was 3226, 3571, and 4348 mg·kg-1, respectively. The ads orption of As and P was fast at the beginning and slowed down then. The kinetics corresponding to the fast process was of first order, and that to the slow proc ess was of Elovich type. The mechanism for the fast process might be exchange ad sorption, and that for the slow process might be specific adsorption. When the A s and P coexisted, the adsorption rate and quantity of P increased while those o f As decreased, implying that the existence of As could promote the adsorption o f P in purple soil, while the existence of P would restrain the adsorption of As.

Effects of CdCl₂ on grape root mitochondrial characteristics and root activity.

SHAO Xiao-jie^1,2;YANG Hong-qiang^1,2;QIAO Hai-tao²;ZHANG Long²;YOU Shu-zhen²

2009, 20(06):  1390-1394 . 

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Taking the one-year cutting-seedlings of four grape cultivars (Kyoho, Muscat Hamburg, Long Yan, and Ze Xiang) as test materials, their root mitochondr ial hydrogen peroxide (H2O2) content, membrane permeability transition pore (MPTP), membrane potential (Δψ), cytochrome C (Cyt c) content, and root activity were measured under effects of CdCl2. For all test grape cultivars, the root mitochondrial H2O2 content and MPTP increased, but the Δψ, Cyt c content, and root activity decreased after treated with 05 mmol CdCl2·L-1. The m itochondrial H2O2 content and Cyt c content were in the sequence of Kyoho>Ze Xiang>Muscat Hamburg>Long Yan, while the root activity, MPTP, and Δψ were in ad verse, i.e., Long Yan>Muscat Hamburg>Ze Xiang>Kyoho. Among the test grape cultiv ars, the root activity of Kyoho was easier to be inhibited under Cd stress, while t hat of Long Yan was least affected by CdCl2.

Effects of exogenous NO on ascorbate-glutathione cycle in loquat leaves under low temperature stress.

WU Jin-cheng;CHEN Jian-qin;LIANG Jie;YANG Wei-bo;WU Jing-jing; CHEN Li-qin;LIU Mei-qiong;CHEN Li-ping

2009, 20(06):  1395-1400 . 

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Three-year-old ‘Zaozhong No. 6’ loquat (Eriobotrya japonica Lindl.) seed lings were foliar-sprayed with 02, 05, 10 and 15 mmol·L-1 o f sodium nitroprusside (SNP), subjected to low temperature (-3 ℃) stress for 6 hours, and then cultured at 25 ℃ for four days. The antioxidant metabolites and enzymes in the seedling leaves were determined 0, 1, and 4 days after recovery. Comparing with the control (water spraying), all SNP treatments had a decreased H2O2 content but an increased content of glutathione (GSH) and ascorbic aci d (AsA) and increased activity of ascorbate peroxidase (APX), glutathione reduct ase (GR), dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase ( MDAR) in the seedling leaves. Four days after recovery, the H2O2 content in the seedling leaves treated with 05 mmol·L-1 of SNP decreased by 7553 %, while the GSH and AsA contents and the APX, GR, DHAR and MDAR activities were increased by 2912%, 2340%, 500%, 444%, 4953%, and 6268%, respectivel y. All of these suggested that appropriate dosage of exogenous NO could enhance the activity of antioxidant system in loquat leaves and alleviated the cell inju ry of loquat leaves under low temperature stress. In this study, the appropriate dosage of NO was 05 mmol·L-1 of SNP.

Interactive relations between agroecosystem and economic system in Loess Hilly Region-A case of Zhifanggou small watershed, Ansai County.

LIU Jia¹;WANG Ji-jun^1,2

2009, 20(06):  1401-1407 . 

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Based on the investigation data in 1938〖KG-*2〗-〖KG-*7〗2007 and by using the evaluat ion method of ecosystem service value and the ecological footprint theory, the e cosystem service value and ecological footprint in Zhifanggou watershed of Loess Hilly Region were calculated, with the interactive relations between agroecosys tem and economic system in the watershed analyzed. From 1938 to 2007, Zhifanggou watershed experienced three development stages, i.e., ecological environment de struction with backwardness of economy (1938〖KG-*2〗-〖KG-*7〗1975), eco-envir onment restoration with rapid development of economy (1975〖KG-*2〗-〖KG-*7〗200 0), and well-maintained ecological environment with stable growth of economy (2 000〖KG-*2〗-〖KG-*7〗2007). The interactive relations of the eco-economic syst ems manifested as ecological deterioration, eco-economic adaptive regulation, a nd eco-economic benign interaction.

Landscape pattern change and its ecological effect in Manas River Basin of Xinjiang, China.

ZHANG Hong-feng;OUYANG Zhi-yun;ZHENG Hua;XU Wei-hua

2009, 20(06):  1408-1414 . 

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Based on the 1976, 1989, 2000 and 2005 remote sensing images and related meteorological data, the landscape pattern change and its ecological effect in Manas River Basin of Xinjiang in 1976〖KG-*2〗-〖KG-*7〗2005 were analyzed with GIS and FRAGSTATES. In the study period, the landscape pattern change in the Basin mainly manifested in the increase of farmland, grassland, and residential area while the decrease of forestland, wetland, desert, and snow and ice coverage. At landscape level, the patch number, landscape shape index, and contagion index increased, while Shannon’s diversity index decreased; at class level, there was a greater difference in the heterogeneity index among different kinds of landscape, indicating a complexity of the landscape ecosystem. The landscape pattern change caused the negative ecological effect of wetland area shrinking, but some positive effects such as the decrease of evaporation and the increase of relative humidity. From 1976 to 2005, the wetland area decreased from 4157 km2 to 2974 km2, with a decrement of 28%, evaporation decreased by 091 mm·a-1, and relative humidity increased by 0037%·a-1.

Landscape pattern in Northeast China based on moving window method.

LIU Xin;GUO Qing-xi

2009, 20(06):  1415-1422 . 

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Based on GIS technology and by using moving window method, the charact eristics of landscape pattern in Northeast China in 2006 and the relationships b etween these characteristics and environmental factors such as precipitation, ai r temperature, altitude and human activities were studied. In the study area in 2006, forest land had the largest proportion, followed by the cultivated land, occupying 6169% and 2511% of the total respectively, and the landscape diversity had the characteristics of circle-zoning structur e, which provided a buffer region for fragmented and sensitive regions, making t he adverse ecological consequences be reduced to or restricted in a definite sca le. The correlation coefficients of landscape indices with precipitation and air temperature were less than 04, and those with altitude were less than 007, il lustrating that the heterogeneity of landscape pattern in study area was not dep endent on single natural factors.

Bad tourist behaviors and their environmental impacts on Xixi National Wetland Park in Hangzhou.

WANG Guo-xin^1,2;WANG Ru-song³;MAO Chun-hong⁴

2009, 20(06):  1423-1430 . 

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By the methods of site investigation, data collection and correlation analysis, the bad tourist behaviors and their environmental impacts on Xixi National Wetland Park in 2006 were studied. The occurrence probabilities of three bad tourist behaviors, i.e., picking, trampling, and littering were 65%, 103% and 126%, respectively. Picking probability was primarily related to the vegetation types along walkways, while the scale of heavy trampling was negatively correlated with tour distance from the entrance. Waste production by each tourist was 782 g·d-1 on average. The waste from littering amounted for 136% of the total. Tourist flow fluctuations of daily, weekly, and monthly perspectives for the study area showed high seasonality and successive days of overloaded tourist flows during peak seasons, which caused an increase of bad tourist behaviors. However, the water quality in the Park was not affected because of the improvement of dredging facilities.

Evaluation of resource exploitation value and ecosystem service loss in Mentougou District of Beijing City.

LIU Xu-sheng¹;LI Feng²;ZHAO Dan²;WANG Bei-bei²

2009, 20(06):  1431-1437 . 

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By using the evaluation approach of ecosystem services (including mark et value, opportunity cost, restoration cost, and shadow project approaches), an d combining with situation investigation, the ecosystem service loss in Mentougou District of Beijing City caused by coal resource exploitation in 1949〖KG-*2〗- 〖KG-*7〗2006 was systematically evaluated. In the study area, coal mining mainl y induced the cost increase of solid waste disposal and sink reclamation, and th e losses in food production, water self-preserving, residents moving, and water and soil resources. The ecosystem service loss caused by the coal mining in 194 9〖KG-*2〗-〖KG-*7〗2006 was about 543 billion Yuan RMB, approximately 9 times high of its market economic benefit (59 billion Yuan RMB). It was very diffic ult or needed a long time to restore the damaged ecosystem.

Physiological responses of Gracilaria lemaneiformis to copper stress.

ZHU Xi-feng¹;ZOU Ding-hui^1,2;JIAN Jian-bo¹;CHEN Wei-zhou¹;LIU Hui-hui¹;DU Hong¹

2009, 20(06):  1438-1444 . 

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Gracilaria lemaneiformis was exposed to 0, 25, 50, 100, 250 and 500 μ g·L-1 of Cu2+ to study its physiological responses to Cu2+ st ress. When the Cu2+ concentration was ≥50 μg·L-1, the relative gr owth rate (RGR) of G. lemaneiformis decreased significantly, and the optimal quantum yield (Fv/Fm), the maximum relative electron transfer rate (r ETRmax), and the relative electron transfer efficiency (α) exhibited th e same variation trend, compared with the control. With the increase of Cu2+  concentration, the maximum net photosynthetic rate (Pmax) and l ight saturation point (LSP) decreased significantly, light compensation poin t (LCP) had a significant increase, while chlorophyll a, carotenoid, and phy cobiliprotein contents decreased after an initial increase. When the Cu2+ concentration reached 500 μg·L-1, the chlorophyll a, carotenoid, and phy cobiliprotein contents decreased significantly. It was suggested that G. leman eiformis could tolerate low concentration Cu2+ stress, but its physiolog ical activities were inhibited markedly when exposed to ≥50 μg·L-1 of C u2+.

Fishing grounds characteristics of Illex argentinus in southwest Atlantic.

WU Yu-mei;YANG Sheng-long;SHEN Jian-hua;ZHOU Wei-feng;ZHANG Jing

2009, 20(06):  1445-1451 . 

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Based on the catch amount data of Chinese squid jigger vessels from January to July 2006 and the sea current, sea surface temperature (SST) and chlorophyll-a (chl-a) data derived from satellites, the characteristics of Illex argentinus fishing grounds, their productivity, and environment factors in southwest Atlantic were analyzed. There were two main I. argentinus fishing grounds in southwest Atlantic, one in its south part (60°30′ W, 45°30′ S) and the other in the north part (58°00′ W, 42°00′ S). From January to July, the main fishing grounds migrated from south to north. The productivity fluctuated notably in different months, being higher from January to April and the highest in March. After May, the productivity decreased gradually. The locations of the fishing grounds had close relationships with Falkland cold current. North fishing ground located at the main axis of the current, with a current speed of about 28〖KG-*2〗-〖KG-*7〗60 cm·s-1; and south fishing ground located at the west of the current, with a small scale anticyclone and a current speed of about 5〖KG-*2〗-〖KG-*7〗32 cm·s-1. The favorable SST in the fishing grounds was 7 ℃〖KG-*2〗-〖KG-*7〗15 ℃, with a favorite SST of 12 ℃, and the favorable chl-a concentration was 04〖KG-*2〗-〖KG-*7〗15 mg·m-3, with a favorite chl-a concentration of 09〖KG-*2〗-〖KG-*7〗12 mg·m-3. A significant positive relationship was observed between I. argentinus productivity and chl-a concentration (P<005).

Conversion methods of freshwater snail tissue dry mass and ash free dry mass.

ZHAO Wei-hua^1,2;WANG Hai-jun¹;WANG Hong-zhu¹;LIU Xue-qin¹

2009, 20(06):  1452-1458 . 

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Mollusk biomass is usually expressed as wet mass with shell, but this expression fails to represent real biomass due to the high calcium carbonate content in shells. Tissue dry mass and ash free dry mass are relatively close to real biomass. However, the determination process of these two parameters is very complicated, and thus, it is necessary to establish simple and practical conversion methods for these two parameters. A total of six taxa of freshwater snails (Bellamya sp., Alocinma longicornis, Parafossarulus striatulus, Parafossarulus eximius, Semisulcospira cancellata, and Radix sp.) common in the Yangtze Basin were selected to explore the relations of their five shell dimension parameters, dry and wet mass with shells with their tissue dry mass and ash free dry mass. The regressions of the tissue dry mass and ash free dry mass with the five shell dimension parameters were all exponential (y=axb). Among them, shell width and shell length were more precise (the average percentage error between observed and predicted value being 220% and 225%, respectively) than the other three parameters in the conversion of dry mass. Wet mass with shell could be directly converted to tissue dry mass and ash free dry mass, with an average percentage error of 217%. According to the essence of definition and the errors of conversion, ash free dry mass would be the optimum parameter to express snail biomass.

Species diversity of ground-dwelling beetles on northern slope of Daba Mountain, China.

HE Chun-xia^1,2;DU Pei-yi^1,3;YU Xiao-dong¹;LUO Tian-hong¹;WU Jie¹;ZHAO Cai-yun^1,2;ZHOU Hong-zhang¹

2009, 20(06):  1459-1464 . 

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By using pitfall trapping, the species composition and quantitative distribution of ground-dwelling beetles in man-made plantations in forest farm (MPFF), secondary natural forests in farmland (SFF), and man-made plantations in farmland (MPF) on northern slope of Daba Mountain were analyzed, and detrended correspondence analysis and cluster analysis were adopted to study the similarity of the species composition and quantitative distribution of the beetles among the three forest types. 1094 individuals of ground-dwelling beetles were captured in August 9〖KG-*2〗-〖KG-*7〗13th, 2002. Of these beetles, Staphylinidae and Chrysomelidae accounted for 4059% and 3318% of the total, respectively, and Carabidae, Leiodidae, Scarabaeidae, Curculionidae, Ptiliidae, and Pselaphidae each took more than 1% of the total. These eight families were considered as the common-occurring groups in the study area. The individuals of ground-dwelling beetles decreased from MPFF to SFF to MPF, and the family richness was obviously lower in MPF than in MPFF and SFF. The family composition and abundance of the beetles were significantly different between MPFF and SFF, but partial similarity was observed between MPF and other two forest types.

Genetic polymorphism of blood protein of six Passeriformes species in Zhalong National Nature Reserve.

XU Xing-jun¹;Lü Jian-wei¹;XUAN Li-fang¹;ZHANG Dong-yue^1,2;ZHOU Shuang-tao¹;ZHAO Kan¹;WANG Bin¹;SHAO Shu-li¹

2009, 20(06):  1465-1470 . 

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The polymorphism of hemoglobin (Hb), serum albumin (Alb), trandferring (Tf) and adenosin deaminase (Ada) in the blood of Emberiza elegans, Phylloscopus inornatus, E. aureola, Lanius tigrinus, Passer montanus, and E. spodocephala in Zhalong National Nature Reserve were studied by SDS-polyacrylamide-gel electrophoresis. All the protein loci of the six Passeriformes species exhibited polymorphism, and Ada locus had a relatively high heterozygosity. The analysis of average heterozygosity demonstrated that P. inornatus had a higher population genetic variance, while E. spodocephala was relatively stable. The six species could be classified into two clusters. E. elegans, E. aureola, E. spodocephala and P. inornatus were clustered into one group, while P. montanus and L. tigrinus were clustered into another group. This clustering was consistent with the actual taxonomic status of the six species. The higher thermoregulation index and predation pressure of the study area did not lead to the substantial variation of hereditary constitution of the six species, possibly due to the gene intercommunion between the six species and the outside of the study area, which decreased the variance and differentiation of the population genetics of the six species.

Biological characters of Bemisia tabaci(Gennadius) experimental population on cotton varieties in Xinjiang.

YU Jiang-nan;CHEN Dan;Sailikgli·Hurmanha;LI Jie;SUN Xin-hua

2009, 20(06):  1471-1476 . 

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The development, survival, reproduction, and life-span of Bemisia tabaci (Gennadius) on six major cotton varieties (Xinluzao 8, Xinluz ao 16, Xinluzao 17, Zhongmian 35, Kang 5, and Dai 80) in Xinjiang were studied u nder the conditions of (26±1) ℃, relative humidity (75±1)%, and illumination L ∶〖KG-*2〗D=16∶〖KG-*2〗8 in laboratory. The life table of the B. tabaci e xperimental population was established, and the population net reproductive rate (R0), intrinsic rate of increase (rm), mean generation time (T) , and finite growth rate (λ) were estimated. Significant differences were o bserved in the size, development duration, survival, and fecundity of the experi mental population on the six cotton varieties. The fecundity and survival rate o f B. tabaci were the highest on Xinluzao 16 and the lowest on Kang 5. Xinluz ao 16 was the most appropriate host for the growth and development of B. tabaci population, followed by Zhongmian 35, while Kang 5 was the m ost unsuitable host.

Resistance stability of rice varieties to different biotypes of brown planthopper.

WU Bi-qiu;HUANG Feng-kuan;HUANG Suo-sheng;LONG Li-ping;WEI Su-mei

2009, 20(06):  1477-1482 . 

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In order to develop an effective analytical and monitoring method in b reeding rice varieties with higher resistance stability to brown planthopper (BP H), Tai’s method (1971) was employed to estimate the resistance stability of tw elve rice varieties to different biotypes of BPH. It was shown that light intens ity, seedling age, and nitrogen application rate had significant effects on the resistance performance and stability of rice varieties to different BPH biotypes . Among the varieties with resistance to BPH biotype Ⅱ, the RHT, RP1976-18-6 -4- 2, and Ptb33 showed stable, IR56 showed unstable, while IR36 and ASD7 showed the most unstable resistance; whereas among the varieties susceptible to BPH biotyp e Ⅱ, the TN1 showed stable, Guihuazhan, Foshanyouzhan and IR26 showed relativel y stable, while Guojing No.4 and Mudgo showed unstable susceptibility. For the r ice varieties resistant to BPH biotype Bangladesh, the RHT, RP1976-18-6-4-2 and Ptb33 presented unstable, and IR56 presented very unstable resistance; whereas f or the varieties susceptible to BPH biotype Bangladesh, the Guihuazhan, Foshanyo uzhan and IR26 performed stable, TN1 and IR36 performed unstable, and Guojing No .4, Mudgo and ASD7 performed the most unstable susceptibility.

Perception and attitude of rural community to the construction of Asian elephant conservation corridors in Xishuangbanna.

LI Zheng-ling¹;CHEN Ming-yong³;WU Zhao-lu^1,2;WANG Qian³;DONG Yong-hua³

2009, 20(06):  1483-1487 . 

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By using contingent valuation method (CVM), an investigation was made from November 2007 to March 2008 on the perception and attitude of 196 household s in 5 villages within 2 planned Asian elephant conservation corridors in Xishua ngbanna to the construction of the corridors. 8061% of the interviewees condit ionally supported the corridors construction. The main factors affecting the int erviewees’ support willingness included their education level, per capita incom e, and perceptions to Asian elephant protection, human-elephant relations, and corridor utilization patterns and its beneficiaries, among which, the interviewe es’ awareness of Asian elephant conservation, corridor utilization patterns, an d corridor beneficiaries had strong influence on the support willingness, with t he correlation coefficient being 0231, 0236, and -0304, respectively. The ru ral community holding the land tenure played a key role in the corridors constru ction. To effectively design and planning the construction of biological conserv ation corridor, it is necessary to have a deep understanding on the perceptions and attitudes of rural community to the construction of the corridor and to obta in their support and participation for this construction.

Bioactivity and chemical composition of essential oil from Zanthoxylum beecheyanum var. alatum leaves against Culex pipens quinquefasciatus Diptera: Culicidae).

PENG Ying-hui¹;ZHANG Yun¹;ZENG Dong-qin¹;CHEN Fei-fei¹;ZHONG Hai-yan¹;LI Zhong-hai¹;HUANG Yi²

2009, 20(06):  1488-1494 . 

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The repellent activity of steam-distilled essential oil from Zanthoxlu m beecheyamum var. alatum fresh leaves against Culex pipens quinquefasciatus was evaluated according to the “Laboratory Efficacy Criterions of Public Hea lth Insecticides for Pesticide Registration-Repellent (GB/T 17322.10〖KG-*2〗-〖KG-*7〗1998)” w ith some modifications in test procedure, the fumigating insecticidal activity o f the essential oil to Cx. pipens quinquefasciatus adults was assessed by th e “Efficacy Test Methods of Public Health Insecticides for Pesticide Registrati on-Method of Laboratory Efficacy Test for Electric Mat (GB 139175〖KG-*2〗- 〖KG-*7〗1992)”, and the larvicidal and pupicidal activities of the essential o il against Cx. pipens quinquefasciatus were investigated by immersion method in laboratory. Besides, the chemical components of the essential oil were analy zed and determined by gas chromatography-mass spectrometry. At the dosage of 1. 5 mg·cm-2, the essential oil provided 100% protection against laboratory-rear ed female blood-starved individuals of Cx. pipens quinquefasciatus for （654±017） h. The 24 h LC50 value of the essential oil for Cx. pipens quinquefasciatus adults w as 6895 μg·cm-3 when the fumigating dosage was 11850 μg·cm-3, and the KT50 value of the essential oil for the adults was 646 min. The 24 h LC50 value of the essential oil for IV in star larvae was 119020 μg·ml-1. Seventeen compounds in the essential o il were identified, accounting for 974% of the total. This essential oil exh ibited high repellent activity and remarkable toxicity against Cx. pipens qu inquefasciatus.

Gas exchange measurement system based on chamber method and its applications in gas exchange research of plant ecosystems.

YUAN Feng-hui;GUAN De-xin;WU Jia-bing;WANG An-zhi;JIN Chang-jie

2009, 20(06):  1495-1504 . 

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Gas exchange measurement system based on chamber method is commonly used for the researches of carbon and water cycles in plant ecosystems, especially for the researches in soil and plant organizational scales. According to the gas path frames of the measurement system, this paper summarized in detail the principles and computing methods of closed, semi-closed, open, and semi-open path gas exchange measurement chamber systems. The commercial gas exchange measurement chamber systems commonly in use were enumerated, and the development and applications of some handcrafted systems were also reviewed. Finally, some disadvantages of gas exchange measurement chamber systems were indicated, and their improvement measures were suggested.

Forest carbon cycle model: A review.

WANG Ping

2009, 20(06):  1505-1510 . 

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Forest carbon cycle is one of the important items in the research of t errestrial carbon cycle, while carbon cycle model is an important means in study ing the carbon cycle mechanisms of forest ecosystem and in estimating carbon flu xes. Based on the sum-up of main carbon cycle models, this paper classified the forest carbon cycle models into two categories, i.e., patch scale forest car bon cycle models and regional scale terrestrial carbon cycle models, with their features commented. The future development trend in the research of forest carbo n cycle models in China was discussed.

High temperature stres on crop pollen: A review.

LU Ming-hui;GONG Zhen-hui;CHEN Ru-gang;HUANG Wei;LI Da-wei

2009, 20(06):  1511-1516 . 

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High temperature has already become a noticeable environmental factor for crop production, while plant pollen was the most sensitive organ to high tem perature stress. In this paper, the cytological, physiological, and molecular bi ological studies on the high temperature stress on crop pollen were reviewed, a imed to provide ideas for maintaining high productive ability of crops under hig h temperature stress. The cytological effects of high temperature on crop polle n included the changes of arrangement patterns of rough endoplasmic reticulum in tapetum cells, the irregularity of vascular bundle sheath cells in connective t issue, and the reduction of vesicle production by dictyosomes of pollen tube, etc.; physiological effects involved the incapacity of timely recovery of Ca2+ homeostasis, the changes of growth regulators contents, and the slowing down of car bohydrate metabolism, etc.; and molecular biological effects manifested in the insufficient induction of heat shock proteins and the inhibition of oth er functional genes for pollen development, etc.

Research progress on wetland ecotourism.

WANG Li-long;LU Lin

2009, 20(06):  1517-1524 . 

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Wetland is rich in biodiversity and cultural diversity, possessing higher tourism value and environmental education and community participation functions. Wetland ecotourism reflects the sustainable development of tourism economy and wetland protection, having received great concern from governments and scholars at home and abroad. This paper summarized the related theories and practices, discussed the research advances in wetland ecotourism from the aspects of significance, progress, contents, methods and results, and pointed out the important research fields in the future, aimed to accelerate the development of wetland ecotourism research and to provide reference about the resources exploitation, environment protection, and scientific administration of wetland and related scenic areas.

Effects of salicylic acid on sucrose metabolism of tomato seedlings under NaCl stress.

SU Yue¹;LI Tian-lai¹;LI Nan²;YANG Feng-jun¹;LU Shao-wei¹

2009, 20(06):  1525-1528 . 

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A water culture experiment was conducted with the seedlings of tomato (Lycoper sicon esculentum Mill.) cultivar Liaoyuanduoli to study the effects of salicyl ic acid (SA) on their sucrose metabolism under NaCl stress. The seedlings were t reated with different concentrations (100, 300, and 500 mg·L-1) of SA, and the contents of sucrose, glucose, and fructose as well as the related en zyme activities of sucrose metabolism, including acid invertase (AI), neutral in vertase (NI), sucrose phosphate synthase (SPS), and sucrose synthase (SS), in se edling leaves were determined. Under NaCl stress, SA could maintain or enhance t he leaf fructose and glucose contents and the leaf AI, NI, SPS and SS activities , with the highest increment of fructose and glucose contents being 300% and 311% and that of AI, NI, SPS and SS activities being 247%, 279%, 220 % and 245%, respectively, in comparing with no SA application, while had less effect on the leaf sucrose content, which suggested that SA could play a protec tive role in the NaCl-tolerance of tomato seedlings via enhancing the leaf inve rtase activity to increase leaf fructose and glucose contents. The best alleviat ing effect was observed at 500 mg·L-1 of SA.