Table of Content

25 January 2000, Volume 11 Issue 1

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Dynamics of community structure in successional process of needle and broad-leaved mixed forest in Heishiding of Guangdong

ZAN Qijie, LI Mingguang, WANG Bosun, ZHOU Xianye

2000, (1):  2-5. 

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This paper dealt with the dynamics of community structure in a ten-year succession of needle and broad-leaved mixed forest in Heishiding of Guangdong Province.The vertical community structure tended to be complex, while the horizontal one increased by a wide range.There was no big change in species composition,but the dominance of conifers Pinus massoniana and Cunninghamia lanceolata was substiuted by the broad-leaved species,such as Schima superba,Symplocos adenophylla and Schefflera octophylla. The whole community changed from needle and boad-leaved mixed forest into broad leaved and needle mixed forest.The species diversity and evenness of tree layer were increased,the ecological dominance was decreased,and the community became more complicated.

Individual biomass of natural Pinus densiflora

WANG Cheng, JIN Yonghuan, JIN Chunde, LIU Jisheng, JIN Yushan

2000, (1):  6-9. 

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The aboveground biomass of individuals with different growth potentials in natural Pinus densiflora forest with different stand densities was measured in Yanbian,Jilin Province.The variation of individual biomass affected by densities was in order of dominant tree<intermediate tree<suppressed tree,while the distribution proportion of biomass in different organs affected by densities was:in order of trunk>branch>needle>bark.The biomass components of P.densifliora with different growth potentials varied markedly with the approaching of density class Ⅲ,and the change of intermediate trees was similar to the whole stand.The vertical distributions of biomass of different trees were different from each other,but all showed that the biomass of trunks and barks was mainly distributed below 6 m high from ground,that of branches was within 6～10 m high,that of needles was uniform in the upper,middle and lower layers,and that of branches and needles in upper layer was least affected by density.

Variation of dormancy characteristic of different Pinus bungeana seed sources

WANG Xiaoping, LIU Jinglan, WANG Jiuling

2000, (1):  10-13. 

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Studies on the dormancy characteristics of Pinus bungeana seeds from 7 representative seed sources show that the difference of water permeability of seed capsule was very significant among seed sources.The seeds from northern part of distribution area had a much higher water permeability than from the south.According to water permeability,the seven seed sources were divided into 2 geographical groups, with Qinling Mountain as the division line.The difference of seed ventilation was caused firstly by outer seed capsule,and secondly by inner one.The variation of permeability had a similar trend with the ventilation.The inhibition ability of seed extracts was significantly different among different seed sources,which was increased with the concentration of seed extracts.Based on the inhibition ability of extracts from seed capsule and endosperm,the seven seed sources were divided into 2 and 3 geographical groups,respectively.The germination capacity decreased with increasing latitude,and seeds with poor germination capacity took relatively more time for germination. All population groups based on different division criteria showed such a character,i.e., the difference of seed characteristics was more significant among groups than in same group,and the distance of seed source was longer among groups than in a group.The difference of dormancy characteristics of different P.bungeana seed sources was the result of interaction between climatic and geographical factors.

Light effect of gaps in Huangshan pine community and regeneration of Huangshan pine

WU Zemin, HUANG Chenglin, WEI Chaoling

2000, (1):  14-19. 

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This paper dealt with the gaps of Huangshan pine( Pinus taiwanensis) forest developed on the meadow of 1400～1600m above sea level of Huangshan Mountain.The method of analyzing annual ring growth of pine trees surrounding gaps was employed to estimate the time of gap formation,which was almost the same as the regeneration occurred there.The dynamic variations of total radiation and photosynthetic available radiation(PAR) at different points in gaps were measured,and a regression model for their estimation based on gap size,expanded gap size and canopy closure situation overhead the extended gap was established.The results indicated that the total radiation and PAR were respectively 90% and 71% of full sunlight in gap center, and 30～40% and 25～33% in expanded gaps,while the light under canopy was less than 10% of full sunlight.In the gaps with an area of 40m² or in the extended gaps with an area of 110m²,the light might basically satisfy thegrowth of the pine,and the gap regeneration could occur.It is suggested that man-made gaps could be made to facilitate the regeneration of Huangshan pine,which could be used as a management approach for Huangshan pine forests,and also for maintaining the landscape in beauty spots of Huangshan Mountain.

Spectral characteristics of solar radiation in broadleaved Korean pine forest in Changbai Mountain

JIN Changjie, GUAN Dexin, ZHU Tingyao

2000, (1):  20-22. 

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Based on the measurement above and below forest canopy and meteorological data,the spectral characteristics of solar radiation in broadleaved Korean pine forest in Changbai Mountain was analyzed.The results show that the photosynthetically active radiation(PAP)coeffcients of total radiation,direct radiation and scatter radiation changed daily and yearly,with an annual averages of 0.46,0.43 and 0.56 respectively.The average reflectivity,transmissitvity and absorptivity of single leaves of different tree species in Korean pine forest were 27.0%,23.4%,49.6% respectively.Single leaves nearly absorbed all of the ultraviolet radiation(UV) and 71.8% of photosynthetically active radiation,but transmitted 9.6% and reflected 18.6%.As for near-infrared radiation (NIR),the reflectivity and transmissitivity of leaves were a little less than the absorptivity.The forest canopy absorbed 93.9% PAR and 94.1% UV,but reflected and transmitted less.It absorbed 59.2%,reflected 26.3% and transmitted 14.4% NIR.

Seed rain and seed bank of constructive species in evergreen broadleaved forest at Chongqing Simian Mountain

PENG Jun, LI Xuguang, FU Yongchuan, LIU Yucheng

2000, (1):  23-25. 

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The study shows that the early and late seed rains of constructive tree species in evergreen broadleaved forest at Chongqing Simian Mountain had no activity.The bigger the seeds of the species and the earlier or later the seeds of the species matured,the higher the proportion of the seed rain damaged by animals.The quantitative variation of seed rain,active seed rain and seed bank did not take place at the same time.At early time, the number of seed banks of Castanopsis fargesii,Lithocarpus glabra,Quercus myrsinrefolia,Castanopsis plasyacantha,Cinamomum subavenium. which own more active seed rain increased by geomitric series.The seed banks of Castanopsis orthacantha and Schima argentea were small,only survived a short time,and did not sprout next year.The quantitative dynamics of seed banks and their increasing or decreasing rates were decided by the proportion damaged by animals,dying speed of seeds and their resistance to pathogens and adverse circumstances,and the state of seed germination.

Relationship between flooded situation and poplar growth on beach land of Yangtze river in Anhui

WU Zemin, SUN Qixiang, DUAN Wenxiu

2000, (1):  26-30. 

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Through the analysis on the dynamics of flooding and the annual ring series of poplar trees on the beach land of Yangtze river in Anhui in the period of 1989～1997,the related models on flooded situation and ring growth were built.The results showed that there existed significant differences in flooding time and depth on different elevations of beach land,which made a great influence on the annual ring growth of poplar trees.The maximal flooded depth was more important than flooded time for its influence on ring growth.In addition,the flooded situation in August and September of previous year had a significantly negative influence on the ring growth of current year.The beach land with a maximal flooded depth of more than 2m was not suitable for high productive plantation of timber.It is suggested that a little more dense plantation should be managed for the production of pulp materials.

Population density of Eucalyptus urophylla plantation

HUANG Baoling, LU Chengqun

2000, (1):  31-33. 

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This paper dealt with the relationships and correlation models of the population density of 5.6 years old Eucalyptus urophylla plantation with its crown width,diamter at breast height(DBH),tree height,individual standing volume,stand volume,wood properties and survital rate.The results showed that the population density remarkably affected DBH,individual standing volume,crown width,live branch height,stand volume and wood fiber width;but not affect tree height,basic density of wood,and length of wood fibers.It had a positive relationship with stand volume,live branch height and wood fibers width,and a negative relationship with DBH,individual standing volume and crown width.In addition, E.urophylla had a wide range of reasonable density.For short-rotation puplwoods,the optimum planting density of E.urophylla is 2000 individuals per hectare.

Mixing of Cunninghamia lanceolata with Michelia macclurei and restoration of self sustaining mechanism in G. lanceolata plantation

WANG Silong, LIAO Liping, DENG Shijian, GAO Hong, HUANG Zhiqun

2000, (1):  34-37. 

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The formation of self-sustaining mechanism is one of the major objectives for the sustainable management of plantations.In this study,the incorporation of different proportions of native Michelia macclurei into Cunninghamia lanceolata plantation was practiced to restore the degraded C.lanceolata plantation,and the comparison of nutrient cycling characteristics and soil nutrient concentrations was made among four types of plantation stand with different mixed rate of native M.macclurei representing four different restoration stages of degraded C.lanceolata plantations.With the increase of the proportion of M.macclurei in the plantation,the litterfall and returned nutrients N,P,K,Ca and Mg increased.The nutrient cycling efficiency increased significantly, e.g.,that of N and Mg increased from about 0.1 for the degraded pure C.lanceolata plantation to above 0.5 for the pure M.macclurei plantation.Soil organic matter and nutrients also elevated.It is suggested that the self-sustaining mechanism of the C.lanceolata plantation forest gradually reformed as the proportion of native M.macclurei mixed in the plantation increased. The criteria to determine the proportion of native broad-leaved tree species mixed in C.lanceolata plantations for the purpose of sustainable management should be based on whether the self-sustaining mechanism was reformed and whether the soil nutrient status was improved.

Distribution patterns of root systems of main planting tree species in Weibei Loess Plateau

ZHAO Zhong, LI Peng, WANG Naijiang

2000, (1):  38-40. 

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The vertical patterns of root systems of Pinus tabulaeformis,Robinia pseudoacacia,Platycladus orientalis,Pinus sylvestris var. mongolica,Pinus armandi,Prunus armeniacia var. ansu planted in the Weibei Loess Plateau were studied with soil auger.Site conditions had a significant effect on the vertical root distribution of R.pseudoacacia,of which,soil moisture is the key factor.Soil species and soil structure also had great effect on the distribution. P.tabulaeformis had a maximum rooting depth at its young stage(8 years old),but the root density increased with age. There was a great difference in vertical root distribution among the tree species,of them, R.pseudoaccia rooted deepest,which negated the opinion that R.pseudoacacia is a shallow rooted tree species.According to the vertical root distribution of the tree species,the productivity of these species in the south-facing site of yellow loess soil would be in order of R.pseudoacacia>Prunus armeniacia var. ansu> P.tabulaeformis>P.sylvestris var. mongolica>P.armandi>Platycladus orientalis.

Decomposition process of Chinese fir stump roots and changes of nutrient concentration

HUANG Zhiqun, LIAO liping, GAO Hong, WANG Silong, YU Xiaojun

2000, (1):  41-43. 

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With space as a substitute for time,the changes of the density of stump sapwoods and heartwoods,and the releasing process of major nutrients during the decomposition of Chinese fir stump roots were investigated.The yearly loss rate of the densities of sapwoods and heartwoods was 2.767?10^-2 and 2.255?10^-2 respectively during decomposition.The contents of N and P in sapwoods and roots decreased continually, while those in heartwoods increased during the first stage of decomposition,and then decreased.The K concentration in stump roots decreased remarkably during first two years, and the content of organic substances decreased during the whole decomposition process.The N,P and K concentrations in roots were higher than those in stump sapwoods and heartwoods at the beginning of decomposition,but bet content of organic substance was opposite.

Response of broadleaved Pinus koraiensis forests in Xiaoxinganling Mt to global climate change-a dynamic modeling

DENG Huiping, WU Zhengfang, ZHOU Daowei

2000, (1):  44-47. 

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In this paper,the Forest Gap Model and four General Circulation Models (GCMs) were employed to investigate the dynamic response of broadleaved Pinus koraiensis forests in Xiaoxinganling Mountains of China to global climate change. Under CO₂ doubling which was simulated by the scenarios of Oregon State University and Goddard Institute for Space Studies,the biomass of broadleaved Pinus koraiensis forest increased and the current Picea-Abies-broadleaved Pinus koraiensis forest would gradually develop to Betula costata-Tilia amurensis-Ulmus laciniata-broadleaved Pinus koraiensis forest.Under the scenarios of Geophysical Fluid Dynamics Laboratory at Princeton University and United Kingdom Meteorological Office, Pinus koraiensis and other coniferous species would be replaced by broadleaved species such as Quercus mongolica,Tilia amurensis and Ulmus laciniata, and the broadleaved Pinus koraiensis forest would change to broadleaved forest,due to the great range increasing temperature by the scenarios.The future warming rate would determine the succession of broadleaved Pinus koraiensis forest.

Relationship between main vegetation types and climatic factors in Inner Mongolia

NIU Jianming

2000, (1):  48-53. 

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The relationship between main vegetation types and climate factors in Inner Mongolia was analyzed by using up to date vegetation map,statistics,modeling and spatial simulation of regional climatic factors under the support of GIS.The feasible climatic range of spatial distribution of plant communities was derived from overlaying vegetation map and climate maps.The results showed that the vegetation distribution was obviously in accordance with climate.On the one hand,all the types,not only zonal vegetation,but also mountain,sandy land and low land communities changed gradually from east to west due to the distance to oceans,with a zonal differentiation,Precipitation played an important role in determining this regulation.On the other hand,latitudinal replacement of plant communities occurred with the change of temperature from north to south.In addition,temperature was also the key factor controlling the spatial distribution of vegetation types,such as meadow,steppe,shrub and low land communities on the east and west sides of Daxinganling Mountains.

Comparison of physiological characteristics of different ecotype plants

TAI Peidong, GUO Shuhai, SONG Yufang, SUN Tieheng, LI Peijun, JIANG Shu

2000, (1):  54-57. 

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Studies on the responses of photosynthesis,leaf water content and stoma resistance of 4 different ecotype plants to water stresses showed that their mechanism of drought-resistance was different.Mesic plants limited water loss from transpiration by increasing their stoma resistance,while xeric plants decreased water loss by keeping the high concentration of cell protoplasm.The latter had a higher efficiency of keeping water than the former.The leaf water content and stoma resistance was decreased from mesic to xeric plants,while the net photosynthetic rate per unit leaf was increased, indicating the difference of physiological characteristics among different ecotype plants.

Effect of cutting on vegetation composition and soil properties

ZENG Xibo, LIU Gengling

2000, (1):  58-61. 

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Different cutting experiments were executed on well-grown natural Imperata cylindrica vegetation in red soil region.The biomass of every 6 years cutting was the highest,and the annual cut was the lowest.Annual cutting resulted in the highest total accumulative biomass in 6 years,with a total production of 399.1kg per plot.The species composition was also influenced by the length of cutting period.In the 6th year of experiment,the xylophyta biomass in the treatment of every 6 years cutting accounted for 41.5% of the total biomass,while the herb biomass in the treatment of annual cutting was 99.0% of the total.The length of cutting period also influenced the layer's development of soil profile and the physicochemical properties of soil.In comparing with the treatment of annual cutting, the soil bulk density in the treatment of every 6 years cutting was lower,and the contents of soil organic matter,total nitrogen,available phosphorus and available potassium were higher.

Species composition and distribution of algae in semi desert algal crusts

HU Chunxiang, LIU Yongding, SONG Lirong, HUANG Zebo

2000, (1):  62-66. 

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Twenty-two species of algae, including 10 Cyanophyta,4 Chlorophyta,6 Bacillariophyta and 2 Euglenophyta,were isolated and identified from the semi-desert algal crusts in Shapotou,Ningxia Autonomous Region.The relationship between algae and soil matrix was studied by grinding and superprobe,and the distribution of algal species in eight layers of crusts was examined under light and scanning electron microscopes.It was found that the algae exhibited a layer typed distribution in intermicron, and the layers of algal crust from surface to inner were in order of inorganic mineral protection layer(ca.0.02mm),alga enriched layer(0.02～2.5mm)and sparse algae layer(2.5～5.0mm).The filaments of algae were united with clay mineral by the polysaccharides and protein of their sheath,or extended directly into mineral granules to network and band sand and soil particles.

Application of Quantitative Theory Ⅰ in commenting the relationship of forage species and weed species

TU Xiuliang, LUO Shiming

2000, (1):  67-69. 

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Quantitative Theory Ⅰ was applied to evaluate the influence of managing measures on the relationship of pasture grass and weeds on two typical grasslands of south China.Grazing intensity and fertilizer dosage were the key factors affecting the dominance of pasture grass.The main weed species were E.odoratum,E.rubiginosum,H.perforata,I.anlindrica and E.annua.The suitable density of cattle was 1～4 cattle·hm^-2,and the dosage of fertilizer application was 500～1000kg·hm^-2 for superphoshate,and 150～250kg·hm^-2 for KCl.

Distribution and transferring of carbon in kast soil system of peak forest depression in humid subtropical regon

PAN Genxing, SUN Yuhua, TENG Yongzhong, TAO Yuxiang, HAN Fushun

2000, (1):  70-73. 

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Taking Guilin Yaji Karst Experiment Site as an exemple and with the methods of field monitoring and laboratory analysis,this paper studied the distribution and transferring of carbon in the karst soil system of peak forest depression in the humid subtropical region of China.The carbon pools in biomass,litters and soil organic matter(SOM)and their mobility as expressed by oxidizability and decomposition rate of SOM,the concentration of soil CO₂ and the emission rate of CO₂ from soil were investigated.The mobile carbon pool in the system supplied a rich source of CO₂,which drived the karst process.When active karst process happened in Spring and Summer,over 60% of carbon in the output water was derived from soil CO₂,as traced by D¹³C distribution in the system.Therefore,owing to the carbon transfer in the pathway of air-plant-soil-water,karst process took place rather under soil-rock-water interface than under air-rock-water interface.Thus,the epigenetic karst process was driven and accelerated by soil as an interface of carbon environmental geochemistry.

Effect of modified ammonium bicarbonate on nitrification-denitrification process and NO and N₂O emission

HUANG Bin, CHEN Guanxiong, Oswald Van Cleemput

2000, (1):  74-78. 

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Compared with ammonium bicarbonate(AB),the effect of modified ammonium bicarbonate (MAB) on nitrification and denitrification processes and NO and N₂O emissions in a clay soil (C soil) and a loam soil (L soil) was studied in laboratory (25℃ and 50% WFPS).The inhibition effect of DCD from MAB on nitrification was relatively small in C soil,but considerably great in L soil.Compared with AB,MAB extended 7 days and 33 days for retaining NH₄⁺.During 15 days,the NO emission from C soil and L soil respectively accounted for 0.60% and 1.06% of applied N under AB application (100μg N·g^-1 ),which were as 30 and 12 times as the N₂O emission from corresponding soils.After applying MAB,the emission of NO from C soil and L soil decreased by 67% and 95%,and the emission of N₂O decreased by 64% and 95%,respectively.After 39 days of aerobic incubation,then anaerobically flooded incubation with nitrate addition (200μg KNO₃-N·g^-1 ) for 7 days,the total loss of denitrification in MAB in L soil was 50% less,and N₂O emission was 113% more than in AB in same soil.

Genetic effect of panicle traits of intersubspecific crosses of rice ( Oryza sativa ) and its interaction with environment

LIANG Kangjing

2000, (1):  79-83. 

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The models of genetic effects and genotype譭nvironment interaction for Additive-Dominant-Additive譇dditive epistasis were used to analyze the panicle traits of intersubspecific crosses of rice (Oryza sativa.) in different environments. It was found that significant additive, dominant and additive譨dditive epistatic effects and genotype譭nvironment (GE) interaction were observed in main panicle length, spikelet density, primary branches, total lengths of primary and secondary branches, but the numbers of main panicle and secondary branches showed no significant additive譭nvironment (AE) interaction and dominant譭nvironment (DE) interaction.The seven traits studied were mainly controlled by dominant effects, but branches traits were more obviously affected by DE interaction. Heritabilities analysis showed that the general heritability in broad sense (H_G²) was much larger than other heritabilities. To certain extent,the interaction heritabilities showed their effects in seven panicle traits tested. Heterotic prediction indicated a positive heterosis in all panicle traits except the numbers of primary and secondary branches. GE only influenced the expression extents of heterosis, but was not able to change their directions. According to the predicated genetic effects,IR66158-37,IR65600-85,Minhui63 and R669 were better than other parents in the tactics of breeding for improving panicle traits, because the progenies from these crosses always showed that panicle traits were slightly affected by environment.

Pot experiment on effect of clipping at seedling stage on spring wheat

YUAN Baozhong, ZHAO Songling, SUN Jie

2000, (1):  84-87. 

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Pot experiment on the compensatory effects of spring wheat(Triticum aestivum) at different clipping intensities (simulating herbivory)at seedling stage (three leaves) was conducted in semiarid region of Gansu Province.Under two conditions of 60% and 90% of field water-holding capacity,spring wheat growth was stimulated by clipping at seedling stage,resulting in overcompensation in biological and economic yields,and with more compensation for heavy clipping than light clipping.The overcompensation of the spring wheat was at the cost of more water consumption.

Relationship of NO₃^--N,NO₂^--N accumulation in some crop seeds with N fertilizers application

QIN Yuchuan

2000, (1):  88-91. 

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From 1996 to 1997,the effect of applying organic and chemical fertilizers on NO₃^- and NO₂^- accumulation in crop seeds was studied in four green food bases of kidney beans (Yunan Province),red small beans (Hebei Province),soybeans (Heilongjiang Province), and peanuts (Shandong Province).For kidney beans and red small beans,the highest grey correlation was existed between available N in soil and NO₂^- in seeds,no matter whether organic fertilizer or urea was applied.In organic fertilizer trials,the highest grey correlation appeared in soil pool (between total N and available N)or seed pool (between NO₃^- and NO₂^-),while in chemical N fertilizer trials,it existed between total N in soil and NO₃^- in seeds.For kidney beans and red small beans,the dynamics of NO₃^-/NO₂^- in seeds was different with the kind of fertilizers applied. Extremely significant negative linear correlation and positive linear regression were existed between the content of NO₃^- and NO₂^- in all four crop seeds.

Effect of different source iron on piglet's growth,metabolism and environment

ZHANG Bin, LI Lili, LI Tiejun, Li Haiping

2000, (1):  92-95. 

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In order to approach the effect of different source Fe on piglet's growth, metabolism and environment,an experiment was conducted with 158 suckling pigs from 15 litters,which were randomly allocated to group Ⅰ,Ⅱ and Ⅲ,and fed with diet Ⅰ(basal diet+FeSO₄·H₂O),Ⅱ(basal diet+Fe-citric acid)and Ⅲ(basal diet+Fe-methionine complex),respectively.Each of the diets contained 146mg·kg^-1 Fe.The results show that after the experiment ended, the body weight,daily increment,grades for appearance and behavior,hemoglobin concentration in blood, Fe transferring albumen concentration in plasma,and Fe contents in plasma and liver of 35 days old piglets in group Ⅱ and Ⅲ were higher(P<0.05 or P<0.01)than those in group Ⅰ,while the feed conversion,diarrhea incidence, fecal amount and its Fe content of the piglets in group Ⅱ and Ⅲ were lower (P<0.05 or P<0.01) than those in group Ⅰ.The body weight and daily gain of the piglets in group Ⅲ were also higher (P<0.05) than those in group Ⅱ, but no significant differences (P>0.05) in other traits between group Ⅱ and Ⅲ. It is suggested that Fe-methionine complex and Fe citric acid could improve piglet's health,growth and development,feed conversion,and physiological and biochemical parameters,increase the absorption and utilization of Fe by piglet's body,and decrease the fecal amount and its Fe content.Both of them should be effective and safe Fe sources for suckling pigs.

Insect community and its diversity in Mangrove forest at Yingluo Bay of Guangxi

JIANG Guofang, YAN Zengguang, CEN Ming

2000, (1):  96-99. 

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The insect community and its diversity in mangrove forest at Yingluo Bay of Guangxi were studied in 1995～1996.The results show that there were 195 insect species in the mangrove area,dominated by Crematogaster rogenhoferi,Camponotus tokioensis and Dichocrocris chorophanta.The diversity of insect community was higher in the inside beach than in the middle and outside beaches.Tides and windstorms were the important factors that decided the community composition levels.The principal component affecting the diversity was the species evenness in the inside,middle and outside beaches.

Mating behavioral ecology of Ancylis sativa adult

HAN Guibiao, DU Jiawei, LI Jie

2000, (1):  100-103. 

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The study shows that the mating peak of the overwintering generation adults of Ancylis sativa appeared at 6.0～8.0 hours in their scotophase and the mating activity was more intensive during 2～3 days after eclosion.The higher the temperature was, the later the adults began to mate.For mostadults, the duration of mating was 3～4 hours,with a mean frequency of 3.3 times for males and 1.59 for females.The mating behavior of 2-days old adults shifted from photoperiod 14L◇10D to continuous dark was similar to that at 14L◇10D,all showing an obvious rhythm.When the adults were shifted to continuous light,their mating became inacitive and irregular.The sex pheromone titer of virgin female decreased significantly after mating l hour,and remained low until 48 hours after mating.

Vertical distribution and quantitative dynamics of dominant functional groups of arthropod community in rice fields and estimation of natural enemy effects

HAO Shuguang, ZHANG Xiaoxi, CHENG Xianian

2000, (1):  104-108. 

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The study showed that Lycosid (wolf spider) mainly distributed in the basal part of rice plants,not as wide as we know in past.Tetragnathid did not limited in the upper part of plants,but might translate to middle or lower part when affected by insecticide.The relationship between the vertical distributions of top and basal species was not significant.Besides the amount of natural enemies,the spatial distribution characteristics of natural enemies and brownplanthopper,and the proportion of brownplanthopper to total preys of natural enemies were the factors affecting the role of natural enemies on the population dynamics of brownplanthopper in rice fields.A model to evaluate the effect of natural enemies to brownplanthopper was put forward,which included the messages of quantitative dynamics,spatial distribution and feeding characteristics of natural enemies,brownplanthopper and neutral insects.

Evaluation of plant protectants against pest insects

PANG Xiongfei, ZHANG Maoxin, HOU Youming, JIAO Yi, CEN Yijing

2000, (1):  109-111. 

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An interference index of population control (IIPC) was constructed for investigating the complex effects of plant protectants,including the effects of repelling insect pests away from the plant,deterring the egg laying of adults and the continuation of feeding, and causing death by toxicity. At the same time, indicated by IIPC, the alcohol extracts of some common plants, such as Eucalytus rubusta, Wedelia chinensis etc. and the neem oil gave very good results to protect the plant against Plutella xylostella. The D-C-Tron NR Petroleum Spray Oil (CALTEX) also gave an excellent effect to protect citrus against red mite. All the experiments show the important role of the repellent effect on the pests.

Effect of temperature and food on Spodoptera litura population

ZHU Shude, LU Ziqiang, CHEN Lifang, YU Wei, ZHANG Shaojun

2000, (1):  112-115. 

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The relationship between temperature and development of Spodoptera litura was simulated by the sine modelV(T)=A+Bsin(C₀+C_1e^C₃T+C_2e^-C₃T),and the threshold temperature and thermal requirment for its development at different stages were estimated by the direct optimum method.The model for the relationship between temperature and survival rate was fitted by the experimental data.The theoretical optimum temperature for the development of eggs,young instar larvae,old instar larvae and pupae was 26.7,.24.7,24.9 and 25.8℃,respectively.The life table parameters under different feed conditions (cabbage,lotus,sweet potato,soybean leaves)were estimated by the method of bisexual life table with age structure.At temperature 25℃,the intrinsic rates of increase under the four different feed conidtions were 0.1836,0.1719,0.1778 and 0.1206,respectively.

Response of Capsicum frutescens metapopulation to simulated insect herbivorous behaviors

LIU Chuanhua, ZHONG Zhangcheng, LU Junqiang

2000, (1):  116-119. 

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Based on the theory of metapopulation, this paper studied the response of different leaf-cutting Capsicum frutescens metapopulation to simulated short-term insect pestes during high temperature period in July.Variance analysis (ANOVA),principal component analysis(PCA)and plant growth analysis were applied.The result shows that C.frutescens had a strong compensatory ability.The number,dry weight and leaf area of old leaves decreased with increasing leaf cutting,but contrarily for new leaves.The total leaf number did not show any significant difference,but the total area and weight of leaves were significantly different,because of the influence of old leaves.The number,weight and lenght of branches were not significantly different with different treatments, and the number of fruits,flowers and flower buds also showed no significant difference.However,the difference of their dry weights was significant.It is practical to use number indexes,but not dry weight,leaf area and length for plant growth analysis in metapopulation,when the difference of dry weight between modulars is small.It is suggested that a certain degree of herbivory might be beneficial to the growth and fruit yield of C.frutescens during the high temperature period.

Effect of Bacillus megaterium on Gluconobacter oxydans in mixed culture

FENG Shu, ZHANG Zhou, ZHANG Chenggang, ZHANG Zhongze

2000, (1):  120-123. 

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To reveal the relationship between Bacillus megaterium and Gluconobacter oxydans in the mixed culture of vitamin C two-step fermentation,the effect of B.megaterium on the growth of G.oxydans and its synthesizing ability of 2-keto-L-gulonic acid(2KGA) was studied.The bioactive metabolites which could enhance the synthesis of 2KGA were isolated and purified by ultrafiltration,gel chromatography and SDS-polyacrylamide gel electrophoresis.Both the culture supernatant and the cytosol of B.megaterium could promote the proliferation of G.oxydans,and the active component in the culture supernatant was above 100 KDa.The culture suernatant could enhance the conversion of L-sorbose to 2KGA,while the cytosol could not.The active components in B.megaterium culture supernatant had molecular weight of 30～50 KDa and above 100 KDa,and the former was a kind of protein with an apparent molecular weight of about 35 KDa,which consisted of one sort of subunit and contained Fe and Zn elements.

Wetland ecosystems formation and its protection in Yellow River Delta

MU Congru, YANG Linsheng, WANG Jinghua, HU Yuanman, LIN Hengzhang

2000, (1):  124-127. 

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Site investigation,satellite photo analysis and historic material analysis show that the vast neonatal wetlands in Yellow River Delta were created by high concentration sediment of the river and the land-sea evolution.Affected by the regional climate,landform,geological deposition,soil,vegetation and their interactions,the wetlands covered 4.5?10⁵hm², 6.84 ?10⁴hm² of which were artificial wetlands.The wetland ecosystems changed with the waving of the Yellow River Mouth and the land development in the Delta area.From ocean to land,the sublittoral aquatic wetland,eulittoral wetland,eplittoral salt wetland,bulrush-quitch wetland,meadow wetland and land agroecosystem were developed.The wetland ecosystems had abundant biological resources,including 1524 wild animals,300 birds and 1040 fishes,which were changed recently by the oil development and affected by the interruption of Yellow River.Wetland protection should be strengthened in resources utilization.

Landscape heterogeneity of urban vegetation in Guangzhou

LI Zhen, WANG Lirong, GUAN Dongsheng

2000, (1):  128-131. 

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Seven indexes were used to study the landscape heterogeneity of vegetation in Guangzhou City.The results show that the patch density was 11.8 patches穔m^-2 and the line corridor density was 1.87km穔m^-2.In old urban area,the vegetation landscape was characterized by small patches,heavy fragmentation,high diversity and random distribution,showing a highly heterogeneous spatial pattern, while in new urban area,the vegetation landscape was characterized by big patches and even distribution.Therefore,when the size of vegetation area was the same,the even distribution of vegetation could improve the landscape heterogeneity and make the ecological function more effective.

Parasitic metamorphosis development of Lamprotula fibrosa

YANG Xuefen, GONG Shiyuan, ZHANG Xunpu, WANG Mingxue, ZHU Ziyi

2000, (1):  132-135,152. 

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The glochidia of Lamprotula fibrosa develop to maturity in the outer gill of female and are expelled to the outside in winter, and then,the mature glochidia are parasitized to the gill of fish host and start the parasitic metamorphosis development.The parasitic period lasts about 4 months.The inner and outer byssuses disappear after parasitizing for 3 days.The foots develop after 35 days.The intestine,adductor muscle,nephridium and gill anlage develop after 90 days.The shells become thick and protrusive.The glochidia become larvae with a size of 253.37×273.26×179.96μm in the next spring,then leave the gill of fish host,and start their independent life.

Influence of fluctuating ecological factors on male occurrence of Moina macrocopa

WANG Jinqiu, ZHANG Jiayi, HUANG Bo

2000, (1):  136-138. 

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Studies with clonal culture show that female M.macrocopa did not produce male progeny directly,or,in other words,the parthenogenetic(amictic) female could not transform into microtic(amphoteric) female,when suffered from one-off acute or durative progressive stimulation.Under durative progressive stimulation by illumination,temperature,food density or pH,the intrinsic rates of increase were 0.7748,0.7481,0.6539 and 0.6310 d -1 ind -1,0.9%,4.0%, 16.4 % and 19.3% less than the control,respectively,indicating that the animal was more sensitive to the fluctuation of food density and pH followed by temperature.

Numerical dynamics of sediment bacteria in shrimp polycultural ecosystems

LIU Guocai, LI Deshang, DONG Shuanglin, WANG Kun

2000, (1):  139-141. 

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The numerical dynamics of sediment bacteria was studied from May to September 1997, in the Shrimp Farm of Huanghai Fisheries Group Corporation with five experimental enclosures. It shows that the numbers of sediment bacteria ranged from 4.10×10⁸ to 12.36×10⁸ cells·g^-1,averaged 8.09×10⁸±2.17×10⁸ cells·g^-1,and increased gradually with increasing cultural time.The maximum was in 0～1cm layer,and decreased obviously bellow 2～3cm layer.

Biological purification of saline chemical wastewater and variation of algological indicatiors

GAO Yurong

2000, (1):  142-146. 

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Simulation pond experiment shows that from the entrance to the exit of the pond,the concentration of pollutants was decreased,while the species, diversity index and primary productivity of algae were gradually increased with increasing purification duration.The dominant algae species changed from high tolerance species to medium tolerant species.Algae quantity and chlorophyll-a concentration remarkably increased.Through 32 days,the purified water flowed out from the third grade pond.The relationships between algae quantity,biomass and chlorophyll-a concentration and the contents of BOD₅,COD,NH₃-N and PO₄-P could be described with the second order equation.Temperature had an obvious effect on the algae growth and purification effectiveness.The optimum temperature condition for algae growth and wastewater purification was in the range of 20～25℃.

Ecological effect of CdCl₂ on plasmid and role of plasmid in Cd-tolerance of its host

MENG Ling, WANG Huanxiao, TAN Deyong

2000, (1):  147-149. 

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After treating the plasmid of Escherichia coli HB101 by CdCl₂ in vitro or in vivo,the effect of Cd on the structure of plasmid pWH58 DNA was studied through argarose gel electrophesis and restriction fragment length polymorphism analysis.By comparing the growth of E.coli with and without plasmid cultured in the medium with Amp LB and non anti LB under different concentrations of CdCl₂,the effect of Cd on plasmid E.coli of in vivo and the role of plasmid in Cd-tolerance of its host were studied.Cd treatments of E.coli in vitro or in vivo didn't cause an obvious change of the structure of plasmid pWH58 DNA.Plasmid pWh58 could replicate for regeneration and gene express under Cd stress.Plasmid pWH58 of E.coli in vivo lowered Cd-tolerance of its host form 75mg稬^-1 to 50mg稬^-1.Cd-tolerance of E.coli ascended markedly after Cd taming,but had a trend of reversing to original level after restoration,indicating that Cd-tolerance of E.coli could be tamed,but the tamed Cd tolerance still had no genetic basis.

Dynamic features of some biochemical constituents in Gynostemma pentaphyllum under different environments

HE Weiming, ZHONG Zhangcheng

2000, (1):  150-152. 

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With biochemical techniques, the authors preliminarilty examined the dynamics of polyphenols,free amino acids and water-soluble sugars in Gynostemma pentaphyllum collected from different regions and the relationships between them and climate factors.The dynamic patterns of these three types of constituents in stems,blades and shoots under the same environment were different.At different growth phases,stems and blades had different contributions to the constituents.The dynamics of them differed with their environments.Polyphenols,free amino acids and water-soluble sugars might regulate the growth and development of plants.Moreover,they were characterized by plasticity,and the dominant climate factors affecting the dynamics of the constituents varied greatly.

Continuous cropping obstacle and rhizospheric microecology Ⅱ Root exudates and phenolic acids

ZHANG Shuxiang, GAO Ziqin

2000, (1):  153-157. 

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This paper discussed the effect of main crop root exudates the relationship between the kinds and amounts of root exudates and the growth of different kinds of crops and their environments. From the aspects of the decompostion of crop residues and the excretion of root systems, the source, form and adsorption mechanism of soil phenolic acids and their effect on crop growth and soil bio-activity were also elaborated.

Utilization of municipal sludge in agriculture and sustainable development

MO Cehui, WU Qitang, CAI Quanying, LI Guirong, JIANG Chengai

2000, (1):  158-161. 

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Based on the ideas of sustainable development,this paper analyzed the features and disposal situations of municipal sludge and its influence on agricultural and urban development.It is suggested that the land application of municipal sludge is significant and urgent for urban and agricultural sustainable development. Land application of sludge will also be basic outlet for sludge disposal in the future. The key of land application of sludge lies in controlling the content of toxic pollutants in sludge and utilizing sludge scientifically.