Loading...
Welcome to Chinese Journal of Applied Ecology! Today is Share:

Table of Content

    05 April 2007, Volume 18 Issue 04
    Articles
    Forest biomass and its dynamics in Pearl River Delta
    YANG Kun; GUAN Dong-sheng
    2007, 18(04):  705-712 . 
    Asbtract ( 3205 )   PDF (1027KB) ( 1460 )  
    Based on the observation data obtained from 69 sampling sites of diffe rent age class forests, and by using biomass expansion factor function, the regr ession equations of stand biomass and volume of the main forest types in Pearl R iver Delta were built, and the regional forest biomass and its dynamics were est imated on the basis of forest inventory data. The results showed that most of th e forests in Pearl River Delta were of young-medium age, which occupied 80% or more of the total forest area, and their undergrowth biomass accounted for abou t 33% of the total forest biomass, indicating that the regional forest biomass c ould be estimated more exactly if undergrowth biomass was fully concerned. In th e periods of 1989〖KG-*2〗-〖KG-*7〗1993, 1994〖KG-*2〗-〖KG-*7〗1998 and 1999〖KG-*2〗-〖KG-*7〗2003, the forest biomass in Pearl Riv er Delta increased by 1467×106 t in total, among which, Pinus massoniana  forest, evergreen broadleaf forest, and conifer and deciduous mixed forest co ntributed about 80%. Young-medium age forest biomass accounted for 90% of the t otal, but the proportion was decreased gradually. The forest area in the Delta a lmost kept unvaried, and the forest biomass was increasing year after year, with an annual increment of about 12%. Better fostering and managing the existing forests is very important to have more forest biomass and better environmental e ffect that regional forests offered.
    Effects of fertilization on fine root biomass of Larix kaempferi plantation
    YU Li-zhong1,2; DING Guo-quan1,3; ZHU Jiao-jun2; SHI Jian-wei1; YU Shui-qiang1; WANG Zheng-quan1
    2007, 18(04):  713-720 . 
    Asbtract ( 2496 )   PDF (944KB) ( 1395 )  
    With 16 years old Larix kaempferi plantation in eastern mountain area of Liaoning Province as test object, this paper studied its total fine root biomass, fine root biomass at different soil depths, and biomass of different root orders under effects of fertilization. The results showed that compared with no fertilization, applying N decreased the total fine root biomass significantly (P<0.05), while the difference between applying P and N+P was not significant. The fine root biomass in top soil (0-10 cm) was significantly (P<0.01) higher than that in subsoil (10-20 cm), and in all treatments, it accounted for 64%-73% of the total. The effects of fertilization on fine root biomass varied with soil depth and root orders. In top soil, N fertilization decreased five orders (except the second order) fine root biomass significantly (P<0.05), while P and P+N fertilization had no significant effects (P>0.05), except the fifth order root in treatment P, and the second order root in treatment P+N (P<0.05). In subsoil, treatments N and P had no effects on five orders fine root biomass (P>0.05), while treatment N+P increased the first order fine root biomass significantly (P<0.05).
    Effects of forest canopy gap on Abies faxoniana seedling’s biomass and its allocation in subalpine coniferous forest of West Sichuan
    XIAN Jun-ren1,2; HU Ting-xing1; ZHANG Yuan-bin3; WANG Kai-yun4
    2007, 18(04):  721-727 . 
    Asbtract ( 2690 )   PDF (1332KB) ( 1697 )  
    By the method of strip transect sampling, the density, height, basal diameter, and components biomass of Abies faxoniana seedlings (H≤100 cm) lived in the forest gap (FG) and under the forest canopy (FC) of subalpine natural coniferous forest in West Sichuan were investigated, and the relationships among different components biomass were analyzed. The results indicated that the density and average height (H) of A. faxoniana seedlings were significantly different in FG and under FC, with the values being 12 903 and 2 017 per hectare , and 26.6 cm and 24.3 cm, respectively, while no significant differences were found in average basal diameter (D) and biomass. The biomass allocation in seedling’s components was markedly affected by forest gap. In FG, the biomass ratio of branch to trunk (BRBT) reached the maximum (1.54) at 12th year, and then, declined and fluctuated at 0.69. Under FC, the BRBT was increased with seedlings growth, and exceeded 1.0 at about 15th year. The total biomass and the biomass of leaf, stem, shoot and root grown in FG and under FC were significantly linearly correlated with D2H. There were significant positive correlations among the biomass of different seedling’s components.
    Growth process and diameter structure of Pinus tabulaeformis forest for soil and water conservation in Loess Plateau hilly regions
    ZHANG Guang-can1; LIU Xia1; ZHOU Ze-fu1,2; ZHANG Shu-yong2; LIU Gang1; CHEN Jian1
    2007, 18(04):  728-734 . 
    Asbtract ( 2414 )   PDF (1023KB) ( 1389 )  
    Through stem analysis of sample trees, the biomass, growth process, and diameter structure of two 21 years old Pinus tabulaeformis forests growing on the shady and sunny slopes in Loess Plateau hilly and gully regions were investigated. The results showed that there were distinct differences between these two forests in their tree height, diameter at breast height (DBH), and timber volume. The forest biomass, growth status, and diameter structure on shady slope were superior to those on sunny slope. The fast--growing period of tree height all appeared in the period of 9-13 years, and after 13 years, the annual increment of tree height was larger in shady slope forest than in sunny slope forest, with the increment in the 21st year being 0.26 and 0.1, respectively. The DBH growth of the two forests was declined greatly after 13 years, but the decrement was obviously less in shady slope forest than in sunny slope forest. After 17 years, the annual increment of DBH growth was larger in shady slope forest than in sunny slope forest, with the values being 0.46 cm·a-1 and 0.27 cm·a-1, respectively in the 21st year. Before 13 years, there was little difference in the increment of timber production between the two forests, but the increment after 13 years was larger in shady slope forest than in sunny slope forest,with the values of 0.0023 m3 and 0.0015 m3, respectively in the 21st year . The summit of DBH distribution curve was all partial to left, but the skewness of shady slope forest (SK=0.75) was lower than that of sunny slope forest (SK=1.03), and the kurtosis of shady slope forest (K=1.05) was higher than that of sunny slope forest (K=0.94), indicating that sunny slope forest had a larger stand density than shady slope forest.
    Stem sap flow and water consumption of Tamarix ramosissima in hinterland ofTaklimakan Desert
    XU Hao1,2,3; ZHANG Xi-ming1; YAN Hai-long1,2; YAO Shi-jun1
    2007, 18(04):  735-741 . 
    Asbtract ( 2638 )   PDF (3132KB) ( 1421 )  
    From April to November 2005, the stem sap flow and water consumption of Tamarix ramosissima in the hinterland of Taklimakan Desert was measured by Flow-32 System. The results showed that, in the extremely arid hinterland of Taklimakan Desert and under enough water supply, the average daily water consumption of T. ramosissima with a stem diameter of 3.5 cm and 2.0 cm was 6.322 kg and 1.179 kg, respectively in one growth season. The stem sap flow of T. ramosissima presented a single-peaked curve, with an obvious day and night variation rhythm and fluctuated with environment factors. Under enough water supply, the environmenal factors such as total radiation, wind speed and air temperature were the main factors affecting the stem sap flow, and the dynamics of stem sap flow could be predicted by the liner regression model based on total radiation and wind speed. Because of the extremely arid environment and enough water supply, T. ramosissima had a relatively higher stem sap flow rate and a great water consumption.
    Castanopsis jianfengensis sap flow and its relationships with environmental factors in tropical montane rainforest.
    ZHANG Gang-hua1,2;CHEN Bu-feng1;NIE Jie-zhu2;LIN Ming-xian1
    2007, 18(04):  742-748 . 
    Asbtract ( 2731 )   PDF (1097KB) ( 1341 )  
    By the method of thermal dissipation and using ICT-2000TE apparatus made in Australia, the Castanopsis jianfengensis sap flow and the variations of environmental factors in a mixed tropical montane rainforest at Jianfengling Nature Forest Reserve (18°36′N, 108°52′E, 860 m altitude) were measured synchronously during the dry and rainy seasons, 2002. The results showed that the sap flow density of C. jianfengensis exhibited mono-peak pattern in clear days and multi-peak pattern in cloudy or rainy days. Sap flow density had significant positive correlations with solar radiation, air temperature, vapor pressure deficit and wind speed, but negative correlation with air relative humidity. In dry season, sap flow density was positively correlated with soil temperature but less correlated with soil moisture, while it was in adverse in rainy season, indicating that rainfall had a greater influence on the sap flow. The linear regression patterns between sap flow and environmental factors were built, which all met the significance at 0.01 level with F test. The mean transpiration rate of C. jianfengesis was 103.5 kg·d-1 and 41.3 kg·d-1 for whole tree,and 1.94 mm·d-1 and 0.77 mm·d-1 for the stand in dry and rainy season, respectively.
    Photosynthesis of five magnolia species in Nanjing City in winter and spring
    JIANG Wei-bing; LI Gang; WENG Mang-ling; JIANG Wu; CAO Jing; WANG Liang-ju
    2007, 18(04):  749-755 . 
    Asbtract ( 2253 )   PDF (1289KB) ( 1336 )  
    The photosynthesis and fluorescence characteristics of five magnolia ornamental species naturally distributed in various subtropical areas were studied in Nanjing City in winter and spring. The results showed that the diurnal changes of net photosynthetic rate (Pn) and water use efficiency (WUE) of test species in winter were different from those in spring. The diurnal integral values of Pn, apparent quantum yield (AQY) and carboxylation efficiency (CE) were lower in winter than in spring, and the Fo was higher, while the Fv/Fm, Fv/Fo, ΦPSⅡ, Fv′/Fm′, ETR, qPand NPQ were lower in winter than in spring. The differences among the five species were remarkable, among which,Parakmeria lotungensis and Michelia platypetala mainly distributed in middle-subtropical area had higher diurnal integral values of Pn, AQY, CE and LSP, but lower value of LCP than other species in winter and spring. Their Fv/Fm, Fv/Fo, ΦPSⅡ, Fv′/Fm′, ETR, qP and NPQ were also higher, indicating that they had higher photosynthetic capacity and wider ecological ranges of light adaptability. Manglietia insignis and Michelia wilsonii mainly distributed in southern subtropical area had lower photosynthetic capacity, and their fluorescence parameters were also lower in winter. Grey correlation analysis showed the main factors affecting the Pn of test magnolia species in winter were Ta and PAR.
    Seasonal variations of calorific values of Pinus koraiensis- broadleaved mixed forest litters and soil macrofauna in China temperate zone.
    YIN Xiu-qin1,2; XIN Wei-dong1; QI Yan-hong3
    2007, 18(04):  756-760 . 
    Asbtract ( 2533 )   PDF (756KB) ( 1364 )  
    In this paper, the calorific values of Pinus koraiensis-broadleaved mixed forest litters and soil microfauna in China temperate zone were determined, with their seasonal variation patterns studied. The results showed that both the calorific values and their seasonal variation patterns were differed with the kinds of tree species litters and soil macrofauna in the mixed forest. The mean gross calorific value (GCV) of P. koraiensis litter was the highest (19.71 kJ·g-1), followed by Betula costata (18.22 kJ·g-1), Tilia amurensis (18.13 kJ·g-1), mixed litter (17.91 kJ·g-1),Fraxinus mandshurica (16.94 kJ·g-1), and Acer mono (16.25 kJ·g-1). With the decomposition of litter, the GCV of P. koraiensis and A. mono litters decreased, while that of F. mandshurica litter had little change. The GCV of T. amurensis and B. costata litters presented an increasing trend in the next year of decomposition. Among the marofauna, scolopendra had the highest GCV (22.07 kJ·g-1), followed by earthworm (16.72 kJ·g-1) and diplopod (13.28 kJ·g-1). Earthworm and diplopod had the identical seasonal variation pattern of GCV, while scolopendra was different from them. There was no significant relationship between the seasonal variation of GCV in litters and soil macrofauna.
    Effects of host plants on natural population of Kerria yunnanensis (Hemipterae: Kerridae).
    CHEN You-qing;WANG Shao-yun
    2007, 18(04):  761-765 . 
    Asbtract ( 2461 )   PDF (706KB) ( 1386 )  
    The study on the development, survivorship and reproduction of Kerria yunnanensis on 4 kinds of host trees indicated that in natural environment, the initial K. yunnanensis population density varied from 181.17 individuals on Dalbergia obtusifolia to 145.27 individuals on Ficus facemosa per cm2, realized sex ratio varied from 0.24 on D. obtusifolia and F. cunia to 0.19 on D. balansae, accumulated population mortality from larval to adult varied from 90.03% on D. balansae to 87.05% on F. cunia, and development period from larval to adult ranged from 156 days on D. balansae to 140 days on F. facemosa. The oviposition of K. yunnanensis varied from 536 eggs on D. balansae to 345.86 eggs on F. facemosa, female adult mass varied from 12.62 mg on D. balansae to 9.03 mg on F. cunia, and basic reproduction rate varied from 48.51 on D. balansae to 32.79 on F. facemosa. D. balansae was the most suitable host plant for K. chinensis summer life cycle.
    Trophic niches of Pantholops hodgsoni, Procapra picticaudata and Equus kiang in Kekexili region.
    YIN Bao-fa1; HUAI Hu-yin1; ZHANG Yi-li2; ZHOU Le1; WEI Wan-hong1
    2007, 18(04):  766-770 . 
    Asbtract ( 2650 )   PDF (748KB) ( 1304 )  
    Interspecies competition is the main factor determining the trophic niche width of sympatric species on both ecological and evolutionary levels. In August 2004, a microscopic analysis of feces was made to analyze the diet compositions of Pantholops hodgsoni, Procapra picticaudata and Equus kiang under free-living circumstances between Chuma River and Wudaoliang in the Kekexili National Nature Reserve. The trophic niche widths and overlaps of these herbivorous ungulates were calculated based on the diet compositions, and the results showed that these three ungulates had similar foods, but the proportions of their diet compositions were different. Gramineous plants were the main food sources for P. hodgsoni, P. picticaudata and E. kiang, accounting for 58.7%, 44.57% and 92.28% of the diet, respectively. The trophic niche widths of P. hodgsoni, P. picticaudata and E. kianthese were 0.878, 0.735 and 0.695, and the niche overlaps of P. hodgsoni and E. kiang, P. hodgsoni and P.picticaudata, and E. kiang and P. picticaudata were 0.869, 0.985 and 0.785, respectively, which suggested that there was a potential intense competition among them, especially for P. hodgsoni and P. picticaudata. The relations between competition and coexistence among P. hodgsoni, P. picticaudata and E. kiang were discussed from the viewpoints of their ecological characteristics and trophic ecology.
    Phenotypic plasticity and its regulation of tillers prolonged reproductive growth of Puccinellia tenuiflora population on alkalized meadow in Songnen Plains of China.
    SUN Ju;YANG Yun-fei
    2007, 18(04):  771-776 . 
    Asbtract ( 2344 )   PDF (861KB) ( 1299 )  
    Puccinellia tenuiflora is a salt-tolerant plant of grass family. By the method of random sampling, big samples of reproductive tillers of P. tenuiflora population on the alkalized meadow in the Songnen Plains of China were collected at early heading, heading, flowering, and milky stages, respectively, and the plasticity of their quantitative characters was analyzed. The results showed that except some fluctuations at flowering stage, the tiller height, tiller biomass, spike length and spike biomass of the reproductive tillers at other three growth stages increased significantly every five days with the increasing time of reproductive growth. At each growth stage, tiller height had a significant positive correlation with spike biomass, but a negative correlation with reproductive allocation. With the time of reproductive growth prolonged, the increasing rate of spike biomass at early heading, flowering and milky stages increased in power function with the increase of tiller height. The reproductive allocation decreased linearly by 43.2% and 44.31% at early heading and heading stages, respectively when the reproductive growth time increased ten days, and by 130% at milky stage when the time increased five days. The regulation of the tiller phenotypic plasticity of P. tenuiflora population at its reproductive growth stage followed definite patterns.
    Effects of burial on seed germination characteristics of 65 plant species on Horqin semi-arid steppe.
    YAN Qiao-ling1,2; LIU Zhi-min1; LI Xue-hua1; MA Jun-ling1,2
    2007, 18(04):  777-782 . 
    Asbtract ( 2574 )   PDF (744KB) ( 1398 )  
    The study on the germination characteristics of newly collected and one year-buried seeds of 65 plant species on Horqin semi-arid steppe showed that after one year’s burial, the seeds of 38 plant species still remained their vitality. For the species whose freshly collected seeds had a germination rate higher than 80%, the seed germination rate after burial was decreased, while it was in adverse for those whose freshly collected seeds had a germination rate less than 80%. The effects of burial on seed germination varied with the ecological types of the species (i . e . , weed, steppe species, meadow species, and psammophytes). After one year’s burial, the germination rate of perennials had no significant increase, but that of annuals increased significantly (P<0.05). The species with a <10% difference of germination rate between their freshly collected and one year-buried seeds could be classified into three categories, according to the seed germination pattern,i . e ., germination was promoted by burial (e . g .Artemisia halodendron), restrained by burial (e. g. A. sieversiana); and unchanged after burial (e.g. Lappula myosotis).
    Niche characteristics of typical marsh wetland plant populations in Sanjiang Plain
    XU Zhi-guo1,2;HE Yan3;YAN Bai-xing1;SONG Chang-chun1
    2007, 18(04):  783-787 . 
    Asbtract ( 2654 )   PDF (641KB) ( 1471 )  
    Based on field investigation and by using Levins formulae, the niche breadth and niche overlap of dominant plant populations in Sanjiang Plain marsh wetland were studied. The results showed that the niche breadth of test marsh wetland plants decreased in the order of Carex pseudocuraica (0.907)>C. lasiocarpa(0.864)>Glyceria spiculosa (0.855)>Deyeuxia angustifolia (0.500)=Menyanthes trifotiata (0.500)=Naumburgia thyrsiflora (0.500)=Anemone dichotoma (0.500). The niche overlaps among C. lasiocarpa, C. pseudocuraica, M. trifotiata and N. thyrsiflora, and among G. spiculosa, D. angustifolia and A. dichotom were comparatively large, indicating an intense competition among them, while the niche overlap between M. trifotiata and N. thyrsiflora, and D. angustifolia and A. dichotoma was 0, suggesting their different manner of environmental adaptation. Soil water was the dominating environmental factor of wetland plant ecological adaptability. The niche fitness of plant to environment depended on the combined effect of soil water and nutrients. The niche characteristics of marsh wetland plants could better indicate their ecological adaptability and distribution range.
    Landscape change during rapid urbanization in Shenzhen.
    SONG Yan-tun1; YU Shi-xiao1; LI Nan2; LI Yong2
    2007, 18(04):  788-794 . 
    Asbtract ( 2440 )   PDF (2657KB) ( 1483 )  
    By using the satellite images of 4 periods of time, including the data from Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), Multi Spectral Scanner (MSS) and SPOT, this paper analyzed the landscape change in Shenzhen Special Economic Zone of Guangdong Province, South China in 1979-2003, aimed to study the temporal-spatial landscape change characteristics, their causes, and major driving forces in this zone. The results revealed that the characteristics of landscape change were completely different among test three periods (1979-1990, 1990-2000 and 2000-2003). During the first period (1979-1990), urbanization developed very rapidly, and the natural vegetations mainly in Futian, Luohu and Yantian districts degraded and transformed into a landscape with anthropogenic components. In the second period (1990-2000), landscape conversion mainly took place in Nanshan and Futian districts, where various types of landscape were transformed into impervious surfaces, and parts of the vegetations were transformed into anthropogenic landscapes. During this period, typical urban characteristics were formed, whereas the remaining vegetations, especially forest stand, were little disturbed. In the third period (2000-2003), subtle consolidation was observed, and the use of pervious material in certain areas counteracted the adverse ecological impacts of urbanization. The extent of urbanization still increased, but the intensity of landscape change was at lower level than that in previous periods.
    Effects of different ridge-furrow planting patterns of potato on soil evaporation in semiarid area.
    TIAN Yuan1; LI Feng-min2; LIU Xiao-lan1
    2007, 18(04):  795-800 . 
    Asbtract ( 2528 )   PDF (1788KB) ( 1336 )  
    This paper studied the soil evaporation in potato field in semi-arid area under effects of covering ridge with plastic film (CR), uncovering ridge but compacted (UR), and belt planting on flat soil without ridge (CK). The results showed that in the whole growth season of potato, soil evaporation was 122.9-165 mm, 90.9-101.2 mm, and 80.7 mm under CR, UR, and CK, respectively. Treatment CR60 had the maximum soil evaporation (2.6 mm·d-1) at maturing stage, with a mean of 1。46 mm·d-1, while the soil evaporation in CK was 0。65 mm·d-1. In treatment UR30, soil evaporation was the minimum (0。2 mm·d-1) at seedling stage, with a mean of 0。39 mm·d-1, while CK was 0。58 mm·d-1. However, water surface evaporation was the maximum at budding and flowering stages, with the daily average evaporation being 8.3 mm and 9.0 mm, respectively, and not in-phase with soil evaporation. At maturing stage, soil evaporation was the maximum in all treatments. It was suggested that covered ridge had high efficiency of rainfall harvesting, but owing to its maximum soil evaporation, measures should be taken to inhibit soil evaporation to increase water use efficiency.
    Monitoring of pollen-mediated gene flow from transgenic Bt cotton.
    WANG Chang-yong1,2; LIU Yan2; ZHOU Jun1; CHEN Jian-qun1; QIN Pei1
    2007, 18(04):  801-806 . 
    Asbtract ( 2523 )   PDF (896KB) ( 1347 )  
    By the methods of pollen grain dyeing and PCR analysis, this paper measured the distance and intensity of pollen dispersal, and determined the frequency of gene flow (FGF) of transgenic Bt cotton. The results showed that the frequency of pollen dispersal (FPD) among flowers was significantly higher on the same cotton plant than on different ones (P<0.01). The average FPD at a distance of 1 m from the dyed Bt cotton plot to its east, south, west and north was estimated to be 44.8%, 48.9%, 57.1% and 21.5%,respectively, and declined with increasing distance in the four directions. Within the range of 25 m, the distance and direction of pollen dispersal could affect FGF significantly (P<0.01), and FGF generally tended to decrease with increasing distance from the Bt cotton plot, with a frequency of 2.0% at the farthest distance of 25m.
    Responses and corresponding physiological mechanisms of different wheat varieties in their nitrogen efficiency and nitrogen uptake to nitrogen supply.
    HAN Sheng-fang1,2; LI Shu-wen3; WU Li-qiang2; WEN Hong-da3; XIAO Kai1
    2007, 18(04):  807-812 . 
    Asbtract ( 2511 )   PDF (694KB) ( 1370 )  
    In this paper, the biological traits, physiological parameters, and enzyme activities related to N assimilation and metabolism of wheat varieties with different nitrogen (N) efficiency were studied under low and high N supply. The results showed that under low N supply, the dry mass of root, leaf, and stem as well as the accumulated N amount in plant were in the order of high N efficiency variety>mid N efficiency variety>low N efficiency variety. The variety with high N uptake efficiency (Ji 97-6360) under low N supply had the highest root active absorption area and TTC-reductive activity and the highest leaf nitrate reductase activity and NO3-content, while the variety with high N physiological efficiency (Shixin 5418) had higher nitrite reductase and glutamine synthetase activities but lower NO3- content and NR activity in its leaf. There was a significant positive correlation between nitrogen use efficiency (NUE) and nitrogen uptake index (NUI) under low N supply. The biological traits, physiological parameters, and enzyme activities related to nitrogen assimilation and metabolism of test wheat varieties were not always the same under high and low N supply.
    Effects of potassium humate on ginger root growth and its active oxygen metabolism
    LIANG Tai-bo; WANG Zhen-lin; WANG Ru-juan; LIU Lan-lan; SHI Chun-yu
    2007, 18(04):  813-817 . 
    Asbtract ( 2557 )   PDF (807KB) ( 1262 )  
    A pool-culture experiment was conducted to study the effects of potassium humate on the growth and active oxygen metabolism of ginger root. The results showed that applying potassium humate increased the root fresh mass and root vigor significantly, and promoted the root growth especially in later period. Potassium humate application obviously increased the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), decreased the content of MDA,and delayed the senescence of ginger root. After applying potassium humate, the soluble protein content in root was increased by 49.18%, 25.89% and 13.26%, and the yield was increased by 61.29%, 48.13% and 9.92%, respectively, compared with the treatments CK, same application rate of humic acid, and same application rate of potassium monoxide.
    Effects of straw application and earthworm inoculation on soil labile organic carbon
    YU Jian-guang; LI Hui-xin; CHEN Xiao-yun; HU Feng
    2007, 18(04):  818-824 . 
    Asbtract ( 3024 )   PDF (753KB) ( 1481 )  
    A six-year field plot experiment of rice-wheat rotation was conducted to study the effects of straw application and earthworm inoculation on cropland soil organic carbon and labile organic carbon. Five treatments were installed, i. e. , CK, straw mulch (M), straw mulch plus earthworm inoculation (ME), incorporated straw with soil (I), and incorporated straw with soil plus earthworm inoculation (IE). The results showed that soil organic carbon content increased significantly after six years straw application, and treatment I was more efficient than treatment M. Earthworm inoculation under straw application had no significant effects on soil organic carbon content. Straw application, whether straw mulch or incorporated straw with soil, increased the content of soil labile organic carbon, and incorporated straw with soil was more beneficial to the increase of the contents of hot water-extractable carbon, potentially mineralizable carbon, acid-extractable carbon, readily oxidizable carbon, particulate organic carbon,and light fraction organic carbon. There was a little relationship between the quantitative variations of soil dissoluble organic carbon and microbial biomass carbon and the patterns of straw application. Among the treatments, the activity of soil organic carbon was decreased in the order of IE>I>M>ME>CK. Straw application pattern was the main factor affecting soil organic carbon and labile organic carbon, while earthworm inoculation was not universally significantly effective to all kinds of soil labile organic carbon.
    Effects of arbuscular mycorrhizal fungi on reactive oxygen metabolism of Citrus tangerine leaves under water stress.
    WU Qiang-sheng1,2; ZOU Ying-ning2; XIA Ren-xue1
    2007, 18(04):  825-830 . 
    Asbtract ( 2453 )   PDF (801KB) ( 1470 )  
    In a pot experiment, this paper studied the effects of arbuscular mycorrhizal (AM) fungus Glomus versiforme (Karsten) Berch inoculation on the reactive oxygen metabolism of Citrus tangerine Hort. ex Tanaka leaves under water stress. The results showed that water stress decreased the colonization of G. versiforme on C. tangerine roots significantly, with a decrement of 33%. Under normal water supply and water stress, G. versiforme inoculation increased the leaf P content by 45% and 27%, and decreased the leaf malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents by 25% and 21%, and 16% and 16%, respectively, compared with the control. Inoculation with G. versiforme enhanced the activities of leaf superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX), and increased the contents of leaf soluble protein, ascorbate (ASC) and total ascorbate (TASC) notably, regardless soil moisture condition. Under water stress, G. versiforme inoculation decreased the leaf superoxide anion radical (O2-·) content by 31%, compared with that under normal water supply. It was suggested that the drought resistance of C. tangerine leaves was enhanced after G.versiforme inoculation.
    Effects of NaCl stress on polyamine contents in grafted cucumber leaves.
    YANG Li-fei; ZHU Yue-lin; HU Chun-mei; LIU Zheng-lu; ZHANG Gu-wen; WEI Guo-ping
    2007, 18(04):  831-836 . 
    Asbtract ( 2404 )   PDF (668KB) ( 1336 )  
    With a Japanese salt-tolerant pumpkin cultivar ‘King Shintosa’(Cucurbita maxima × C. moschata) as rootstock and a cucumber (Cucumis sativus) cultivar ‘Xintaimici’ as cion, this paper studied the temporal dynamics of different form polyamines contents in the leaves of grafted and own-rooted cucumber plants under 100 mmol·L-1 NaCl stress. The results showed that the free putrescence (Put) content of graftedplant leaves (G2) was significantly higher than that of own-rooted plant leaves (O2), except on the second day of NaCl stress. During the whole period of NaCl stress, the free spermidine (Spd) and spermine (Spm) contents of G2 were significantly higher than those of O2, and the total free polyamine content of G2 peaked on the fourth day of stress. The free Put/PAs value of G2 was significantly lower than that of O2 except on the fourth day of stress, but (Spd+Spm)/Put value was significantly higher than that of O2 during the whole period of stress. In the test period, the contents of conjugated and bound Put, Spd, Spm of G2 were significantly higher than those of O2. The total conjugated and bound polyamine contents of G2 peaked on the sixth day of stress. Both conjugated Put/PAs and conjugated (Spd+Spm)/Put values had a similar changing trend to free polyamine. The bound Put/PAs value of G2 was significantly lower than that of O2 except on the sixth day of stress, while the bound (Spd+Spm)/Put value was significantly higher than that of O2 during the whole period of stress. All of these demonstrated that grafted cucumber plant possessed a stronger salt tolerance.
    Effects of bagging on the microenvironment, yield and quality of overwintering tomato
    WANG Lei1,2; XU Kun1; BEI Feng3; GAO Fang-sheng4
    2007, 18(04):  837-842 . 
    Asbtract ( 2898 )   PDF (899KB) ( 1464 )  
    Taking overwintering tomato variety “L402” as test material, this paper studied the effects of bagging with different texture bags on its fruit enlarging and quality, and the microenvironment within the bags. The results showed that bagging could change the microenvironment of fruit development, promote fruit maturing in advance, and improve fruit mass and quality. The light intensity and humidity in parchment bag were at the intermediate of those in plastic and no-spinning cloth bags, and the temperature was the highest among all treatments , except that it was lower than that in plastic bag at forenoon. The fruit enlarging rate in parchment bag was also the highest, and the single fruit mass increased by 15.34%, compared with the control. However, the fruit soluble solid, soluble sugar, and vitamine C contents and the sugar/acid ratio in all bagging treatments were lower than those of the control, suggesting that bagging debased the nutritive quality and the tastiness of tomato fruit. Due to the fact that bagging prevented the direct contact of fruit with pesticides, the fruit chlorpyrifos and betacypermethrin contents in parchment and plastic bags were lower than the control, except that the chlorpyrifos content in no-spinning cloth bag was higher.
    Genetic diversity of microbial communities in tea orchard soil.
    XUE Dong; YAO Huai-ying; HUANG Chang-yong
    2007, 18(04):  843-847 . 
    Asbtract ( 2567 )   PDF (905KB) ( 1333 )  
    In this paper, the total microbial DNA was extracted from the soils in 8-, 50- and 90 years old tea orchards, adjacent wasteland, and 90 years old forestland in Meijiawu tea area of Hangzhou. The 16S rDNA V3 fragment was amplified by PCR, and the polymorphism of this fragment was analyzed by DGGE. The results indicated that both the tea orchard age and the land use type had significant effects on soil microbial genetic diversity. There was a significant difference (P<0.05) in the microbial genetic diversity index among wasteland, tea orchards and forestland, which was decreased in the order of wasteland>tea orchard>forestland. For the tea orchards of different ages, the soil microbial genetic diversity index, microbial biomass C, and basal respiration were significantly higher in 50 years old than in 8 and 90 years old tea orchards.
    Effects of simulated nitrogen deposition on competition of weedy species ( Echinochloa crusgalli var. mitis L.) and upland rice (Oryza sativa L.) under different air temperatures
    YANG Xian-yan1; JIANG Qi-qing1; TANG Jian-jun1; CHEN Xin1; HU Shuijin2
    2007, 18(04):  848-852 . 
    Asbtract ( 2306 )   PDF (806KB) ( 1247 )  
    A greenhouse experiment was conducted to study the effects of simulated nitrogen deposition on the growth and competition of C4 weedy species (Echinochloa crusgalli var. mitis L.) and C3 upland rice (Oryza sativa L.) under day/night temperature of 35 ℃/25 ℃ and 30 ℃/20 ℃. The results showed that under day/night temperature 35 ℃/25 ℃, 4.0 g·m-2·a-1 N deposition enhanced the shoot biomass of E. crusgalli and O. sativa by 29.18% and 27.80%, respectively, compared with control. The N and P uptake by E. crusgalli increased by 87.33% and 49.73%, respectively, but no change was found for O. sativa. Under 30 ℃/20 ℃, three N depositions (2, 4 and 6 g·m-1 ·a-1) enhanced the shoot biomass, tiller number, and shoot N and P uptake of E. crusgalli by 48.99%, 72.68% and 36.18%, 111.11%, 122.22% and 144.44%, 108.88%, 129.22% and 134.29%, and 16.53%, 65.05% and 22.47%, respectively, but no changes were observed for O. sativa. Nitrogen deposition significantly increased the shoot biomass ratio of E. crusgalli to O. sativa under 30 ℃/20 ℃, but had no impact on this ratio under 35 ℃/25 ℃. It was suggested that N deposition could enhance the competition of E. crusgalli over O. sativa, especially under lower air temperature.
    Physiological mechanisms of soybean and rice in responses to aluminum stress
    LIU Ni-ge; MO Bing-bo; YAN Xiao-long; SHEN Hong
    2007, 18(04):  853-858 . 
    Asbtract ( 2728 )   PDF (1024KB) ( 1273 )  
    A hydroponic study was conducted on the root growth, nutrient uptake,and root extracts and exudates of soybean and rice under aluminum (Al) stress. The results showed that low Al (10 μmol·L-1) stimulated the seed germination and root growth of soybean, but had no obvious promotion effects on rice. Al stress increased the P uptake, but decreased the K, Ca and Mg uptake by both soybean and rice. Rice accumulated less Al and more P than soybean. When exposed to Al stress, the soluble protein content in soybean and rice roots increased, soluble phenol decreased, while soluble sugar increased first and decreased then. The citrate content in soybean roots decreased obviously under Al stress. Compared with soybean, rice accumulated more soluble protein and phenol and less citrate, but no difference was observed in soluble sugar content. Al increased the exudation of citrate and soluble protein, phenol and sugar from soybean roots. Under Al stress, soybean roots possessed a higher cation exchange capacity than rice roots. It was suggested that soybean and rice had different physiological responses to Al stress. The Al tolerance of rice was probably associated with its higher P uptake and lower cation exchange capacity than soybean, while root exudates had no significant correlation with its Al tolerance.
    Identification of volatiles from field cotton plant under different induction treatments.
    YU Hui-lin1,2; ZHANG Yong-jun1; PAN Wen-liang3; GUO Yu-yuan1; GAO Xi-wu2
    2007, 18(04):  859-864 . 
    Asbtract ( 2614 )   PDF (2576KB) ( 1442 )  
    The volatiles of field cotton plant at its squaring stage were analyzed qualitatively and quantitatively under treatments of mechanical injury (treatment A), cotton bollworm (CBW) injury (treatment B), CBW plus CBW larva injury (treatment C), and salicylic acid (SA) inducement (treatment D). The volatiles were gathered in an automatic circle system, absorbed by Tenax-TA column, and analyzed with GC-MS system. About 30 kinds of volatiles were qualitatively identified, including terpenoids, aliphatic compounds, aromatic compounds, 3-hexanone, 2-hexanone, 3-hexanol, a-pinene, β-pinene,β-myrcene, propenoic acid, butyl ester, acetic acid, pentyl ester, acetic acid , butyl ester, butanoic acid, 3-methyl-, ethyl ester, benzaldehyde, acetophenone and 1,3,6-octatriene,3,7-dimethyl, etc., and a total of 10 primary volatiles were detected quantitatively. The results showed that both the kinds and the contents of the volatiles were notably higher in treatments B and C than in the control. It was noteworthy that 1,3,6-octatriene 3,7-dimethyl was only found in treatments B and C, i. e. , it only occurred in the cotton plants injured by CBW.There were no significant differences in the kinds and contents of the volatiles between treatment A and the control. Similar to CBW injury, SA inducement also enhanced the release of cotton plant volatiles.
    Roles of infochemicals in host-selection process of Anastatus japonicus.
    CHI Guo-liang; XU Tao; WANG Jian-wu
    2007, 18(04):  865-870 . 
    Asbtract ( 2414 )   PDF (1451KB) ( 1400 )  
    By using a Y-tube olfactometer, this paper studied the selection behavior’s responses of Anastatus japonicus to the volatiles and their individual components emitted from isolated leaves and live plants of different litchi varieties, and to Tessaratoma papillosa. The results showed that among the test litchi varieties, Sanyuehong and Huaizhi had more significant attracting effects to A. japonicus than Nuomici, Guiwei, Feizixiao and Heiye. The two main components of the volatiles from litchi leaves, α-humulene and β-caryophyllene, had no distinct attraction to A. japonicus, but displayed synergistic effect on the host-searching process of natural enemy. When the two components were mixed in equal concentration of 0.3 μl·μl-1, the attracting effect was most remarkable. In a dual-choice experiment, the selectivity of A. japonicus to T. papillosa eggs was not significant, but very remarkable to T. papillosa female adults and to the water extracts from adult abdomen-tip. In a vessel experiment, the numbers of A. japonicus which made selection to T. papillosa eggs and the settling frequency of A. japonicus on the place of T. papillosa eggs were more than those of other treatments. (E)-2-hexenal, one of the most important components of the volatiles of T. papillosa adult, didn’t have evident attracting effect on the adults of A. japonicus.
    Purification function and ecological services value of Crassostrea sp. in Yangtze River estuary.
    QUAN Wei-min1,3; ZHANG Jin-ping2; PING Xian-yin1; SHI Li-yan1; LI Pei-jun2; CHEN Ya-qu1
    2007, 18(04):  871-876 . 
    Asbtract ( 2576 )   PDF (868KB) ( 1418 )  
    Oyster reef ecosystem is a natural decontamination plant of estuarine environment. This paper analyzed the bioaccumulation of heavy metals by Crassostrea sp. population at the dams of Yangtze River estuary, with its purification capacity and ecological services value assessed. The results indicated that Crassostrea sp. had a high capacity in bio-accumulating Cu, Zn and Cd, with the bio-concentration factor (BCF) and biota-sediment accumulation factor (BSAF) being (14.28±2.41)×103, (12.75±2.02)×103 and (14.51±3.71)×103, and 26.78±4.53, 23.24±3.69 and 16.62±4.25, respectively. The bioaccumulation capacity decreased in the order of Cu>Zn>Cd>As>Pb>Hg. The total weight and fresh meat weight of the oyster at the dams of Yangtze River estuary were about 1.07×106 t and 1.75×105 t, respectively, and the total storage of nutrients and heavy metals were 1.462×106 kg N, 1×105 kg P, 24 745 kg Cu, 58 257 kg Zn, 609 kg Pb, 254 kg Cd, 0.18 kg Hg and 329 kg As. The total ecological services value of the oyster reef was estimated at about 8.27×106 RMB·a-1, including habitat value of about 5.10 ×106 RMB·a-1 and environmental value of about 3.17×106 RMB·a-1. Such an environmental value was equivalent to the value of treating about 7.31×106 t combined sewage each year, and corresponded to a large municipal sewage plant with a treatment capacity about 20 000 t·d-1.
    Quality prediction model of greenhouse standard cut chrysanthemum based on light-temperature effect.
    YANG Zai-qiang1,2; LUO Wei-hong1; CHEN Fa-di1; GU Jun-jie3; LI Xiang-mao1; DING Qi-feng1; ZHAO Cai-biao3; LU Ya-fan3
    2007, 18(04):  877-882 . 
    Asbtract ( 2405 )   PDF (1181KB) ( 1508 )  
    Based on the effects of light and temperature on chrysanthemum quality and the experiments with different chrysanthemum varieties and planting dates,a quality prediction model of greenhouse standard cut chrysanthemum with the physiological product of thermal effectiveness and PAR (PTEP) as the measurement scale was developed and validated. The results showed that the predicted results, including the number of unfolding leaves, leaf area, plant height, stem diameter, internode length and flower diameter, accorded well with the observed ones, and the determination coefficient (R2) and relative prediction error (RSE) based on 1∶1 line were 0.99, 0.98, 0.98, 0.92, 0.87 and 0.88, and 5.5%, 6.5%, 5.9%, 4.1%, 11.2%, 12.4%, respectively. This model was of high precision and practicable, which could be used in optimizing the light and temperature management for greenhouse standard cut chrysanthemum production.
    Mathematic models of cucumber net photosynthesis rate responding to CO2 concentration, temperature, and illumination intensity.
    LIU Yu-mei1,3; WANG Yun-cheng2; YU Xian-chang1; LI Yan-su1
    2007, 18(04):  883-887 . 
    Asbtract ( 2907 )   PDF (786KB) ( 1337 )  
    With two cucumber varieties (greenhouse variety Jinyou No. 1 and open-field variety Jinyan No. 4) as test materials, this paper measured their net photosynthesis rate (Pn) under given environmental conditions including CO2 concentration, temperature and illumination intensity in phytotron, and the responses of Pn (y) to these factors were modeled by mathematic methods, which could be described as y=exp(-242.1217/x1)[61.0202-0.11(x2-30.926)2]exp(-272.8874/x3)+0.9355 for Jinyou No. 1, and y=exp(-179.8803/x1)[50.0771-0.0609(x2-34.3455)2]exp(-267.9653/x3)+0.7377 for Jinyan No. 4, where x1, x2 and x3 represented the values of CO2 concentration, temperature, and illumination intensity, respectively. The response of Pn to temperature accorded with conic function, while its responses to CO2 concentration and illumination intensity accorded with exponential function.
    Research progress in soil macropore flow.
    LI Wei-li1,2; JIN Chang-jie1; WANG An-zhi1; PEI Tie-fan1;GUAN De-xin1
    2007, 18(04):  888-894 . 
    Asbtract ( 2407 )   PDF (832KB) ( 1437 )  
    In this paper, the definitions of soil macropore and macropore flow, their types, characteristics, generation mechanisms, and experimental methods in laboratory and field were introduced, and the research progress in their determination techniques, including dye tracing, slice up, penetration curve, tension infiltration apparatus, X-ray CT scanning, and radar exploration were summarized. It was indicated that because of the complexity of the factors affecting soil macropore and macropore flow, the experiments in laboratory should be combined with those in field, and the observation techniques and simulation measures should be further improved.
    Effects and mechanisms of plant roots on slope reinforcement and soil erosion resistance: A research review.
    XIONG Yan-mei; XIA Han-ping; LI Zhi-an; CAI Xi-an
    2007, 18(04):  895-904 . 
    Asbtract ( 2580 )   PDF (1082KB) ( 1339 )  
    Plant roots play an important role in resisting the shallow landslip and topsoil erosion of slopes by raising soil shear strength. Among the models in interpreting the mechanisms of slope reinforcement by plant roots, Wu-Waldron model is a widely accepted one. In this model, the reinforced soil strength by plant roots is positively proportional to average root tensile strength and root area ratio, the two most important factors in evaluating slope reinforcement effect of plant roots. It was found that soil erosion resistance increased with the number of plant roots, though no consistent quantitative functional relationship was observed between them. The increase of soil erosion resistance by plant roots was mainly through the actions of fiber roots less than 1 mm in diameter, while fiber roots enhanced the soil stability to resist water dispersion via increasing the number and diameter of soil water-stable aggregates. Fine roots could also improve soil permeability effectively to decrease runoff and weaken soil erosion.
    Research progress on wind erosion control.
    YI Xiao-yong1,2; ZHAO Ha-lin2; LI Yu-qiang2
    2007, 18(04):  905-911 . 
    Asbtract ( 2477 )   PDF (842KB) ( 1383 )  
    Wind erosion is the main inducement and an important process of desertification, and also, a main environmental problem needed to be controlled in many countries and areas. Based on the formation mechanisms of wind erosion and some important research results, this paper reviewed the biological, chemical, and mechanical measures in wind erosion control, which could be applied individually or integrated together to decrease or prevent wind erosion. It was suggested that management should be strengthened to ensure a better effect in applying these measures to further improve ecological environment.
    Research advances in endophytic fungi of mangrove.
    LIU Ai-rong1,2; WU Xiao-peng1; XU Tong1
    2007, 18(04):  912-918 . 
    Asbtract ( 3034 )   PDF (850KB) ( 1548 )  
    Mangrove, a kind of special host plants, is a resource of abundant endophytic fungi. More than 200 species of endophytic fungi are isolated and identified from mangrove, being the second largest community of marine fungi. The reported endophytic fungi of mangrove are mainly Alternaria, Aspergillus, Cladosporium, Colletotrichum, Fusarium, Paecilomyces, Penicillium, Pestalotiopsis, Phoma, Phomopsis, Phyllosticta and Trichoderma. Most endophytic fungi have wide range of hosts, and a few only have single host. However, the composition and dominant species on each mangrove plant are different. The colonization of endophytic fungi always varies with different parts (leaves, twigs, stems) and age of host plants and with seasons. The endophytic fungi of mangrove can produce many kinds of metabolites with great potential for anti-microbial and anti-tumor medicinal use. In this paper, the research advances in biodiversity of endophytic fungi in mangrove, their distribution, biological and ecological function, and secondary metabolites were reviewed.
    Application of ISSR molecular marker in invasive plant species study.
    GUI Fu-rong1,2,3; GUO Jian-ying1,3; WAN Fang-hao1,3
    2007, 18(04):  919-927 . 
    Asbtract ( 2784 )   PDF (978KB) ( 1400 )  
    Alien species invasion is one of the most important drivers of worldwide environmental change, which may result in environmental degradation, biodiversity loss, and food and water shortage. It may also increase the possibility and severity of natural disasters, and damage international trade and benefits. In last two decades, DNA-based molecular markers were widely used to detect the genetic diversity of invaded alien species. Inter-simple sequence repeat (ISSR) is a microsatellite-based technique, with the superiorities of simple, quick, reliable, and generating higher levels of DNA polymorphism, and being used as a new molecular marker for genetic study. This paper introduced the principles, characteristics and procedures of ISSR, and summarized its applications in studying the genetic structure, genetic diversity, origin, distribution mode, phylogenesis, and breeding features of invasive plants.
    Effects of epiphyte on submerged macrophyte in Taihu Lake.
    SONG Yu-zhi1,2,3; QIN Bo-qiang1; GAO Guang1
    2007, 18(04):  928-932 . 
    Asbtract ( 2547 )   PDF (1870KB) ( 1524 )  
    With the eutrophicated Meiliang Bay and macrophyte-dominated Gonghu Bay of Taihu Lake as test areas, this paper studied the biomass of epiphyte and its effect on submerged macrophyte during the vigorous growth season (May〖-June) of submerged macrophyte in 2005. The results showed that the biomass of epiphyte attached on macrophyte was higher in Gonghu Bay than in Meiliang Bay, and varied within different macrophyte species. The epiphyte inhibited the photosynthetic rate of submerged plant significantly, which could be up to 91.9% in June, and this effect increased with increasing epiphyte biomass but varied with different host plants.
    Carbon storage and carbon fixation during the succession of natural vegetation in wetland ecosystem on east beach of Chongming Island.
    MEI Xue-ying1; ZHANG Xiu-feng2
    2007, 18(04):  933-936 . 
    Asbtract ( 2716 )   PDF (709KB) ( 1300 )  
    Vegetation is an important biological factor in the ecological succession of wetland, and the main factor affecting the carbon storage and carbon fixation in wetland ecosystem. By the methods of field survey and lab analysis, this paper studied the carbon storage and carbon fixation during the succession of wetland vegetation on east beach of Chongming Island, and the results showed that there existed greater differences in the existing carbon storage and its allocation in wetland vegetation at its different succession stages. The existing carbon storage of the pioneer plant Scirpus mariqueter was much less than that of Phragmites australis, only accounted for about 13% of the latter. The underground rhizome of P. australis and the aboveground part of S.mariqueter were the main sites of existing carbon storage. P. australis at the later succession stage of wetland vegetation had a stronger capability of carbon fixation than S. mariqueter at the earlier succession stage of the vegetation, with the values being (1.63±0.39) kg·m-2·a-1 and (0.63±0.28) kg·m-2·a-1, respectively, suggesting that during the succession of S.mariqueter community to P. australis community, the carbon fixation capability of the wetland ecosystem became stronger.
    Pathogenicity of several fungal species on Spodoptera litura.
    LIN Hua-feng; YANG Xin-jun; GAO Yi-bo; LI Shi-guang
    2007, 18(04):  937-940 . 
    Asbtract ( 2325 )   PDF (589KB) ( 1321 )  
    The virulence test of five species of entomogenous fungi Beauveria brongniartii, Beauveria bassiana, Paecilomyces fumosoroseus, Metarhizium anisopliae and Nomuraea rileyi to Spodoptera litura larvae showed that B. brongniartii and N. rileyi had evident pathogenic effects on S. litura, with the LT50 value to S. litura 2nd instars being 2.95 and 4.10 days, and the corrected accumulative mortality of the instars being 100% and 95.2%, respectively. The virulence of B. brongniartii and N. rileyi to the 3rd instars was lower than that of 2nd instars. The LT50 value to 3rd instars was 19.67 and 19.63 days, and the corrected accumulative mortality was 56.6% and 52.2%, respectively. Other two fungal species P.fumosoroseus and B. bassiana also had virulence to S. litura larvae. The LT50 value for the 2nd instars was 4.89 and 6.34 days, and the corrected accumulative mortality reached 85.7% and 71.4%, respectively.