Table of Content

25 January 1993, Volume 4 Issue 1

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Articles

Relationship between seedling growth and dry matter production of spruce in sandy land

Xu Wenduo, Zheng Yuanrun

1993, 4(1):  1-6. 

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The growth characteristics of Picea mongolica seedling and the seasonal dynamics and distribution pattern of dry matter in its various organs during growing seasons are studied using different models. The results show that 1) the growth rate of annual seedlings, and of their root in particular, is much higher, but five years-old seedlings are near to the upper limit of growth, 2) the dry matter production of root, stem and leaf corresponds to Richards model, and the percentages of them to whole plant are different, which reflects the distribution pattern of dry matter in various organs, 3) the dynamics of dry weight of various organs in different years reflects the state of falling leaves and branches caused by self-thinning, and 4) the correlation coefficients simulated by models are almost at very significant level.

Distribution pattern of nutrient elements in masson pine plantation of Anhui province

Zhang Xudong, Xue Minghua, Xu Jun

1993, 4(1):  7-11. 

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The study shows that the content of nutrient elements in various organs of masson pine is in order of needle>branch bark>stem bark>branch wood>stem wood, that in assimilated organ is in order of N>K>Ca>Mg>P, and that in non-assimilated organ is in order of Ca>N>K>Mg>P. The accumulated amount of nutrient elements in various organs is in order of stem wood>stem bark>needle>branch wood>branch bark, that in assimilated organ is in order of N>K>Ca>Mg>P, and that in non-assimilated organ is in order of Ca>N>K>Mg>P. The content of nutrient elements in1000kg dry matter under various site conditions is different. The better site condition, the higher efficiency of nutrient elements, and less accumulated amount. Parent rock, soil depth and total soil nutrient content are the major factors affecting the nutrient content of aboveground organs and of needles in particular. The higher soil Nand Pcontent, the greater biomass in masson pine plantation.

Forecast of larch leaf cast and its control threshold

Wang Yongmin, Yin Tailong, Liu Guorong, Wang Shijun, Fu Ronghua, Tong Ying, Chang Naiqing, Zhang Qiyun

1993, 4(1):  12-17. 

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The forecasting technique of larch leaf cast was investigated in1986—1989, and the supporting system for this forecast and its management is established, which can forecast the current values of forecasting factors, make long-and-medium term forecasting for mean disease index and epidemi area, determine control threshold, work out control plan and predict control benefit.

Photosynthetic characteristics of three species of Dendrobium in Huoshan county of Anhui province

Xu Yunchang, Yu Liwen, Wu Qingsheng, Yang Daoqi, Zhai Liye, Cheng Fujiu

1993, 4(1):  18-21. 

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It's indicated that the light saturation point, light compensation point and net photosynthetic rate of three species of Dendrobiums in Huoshan county are all low and they need feeble and scattered lights for their growth. Relative humidity is the main factor affecting photosynthesis and variation of stomatic aperture. Decreased relative humidity induces decreased net photosynthetic rate. When the air temperature is below 20℃ and relative humidity is above 80%, the stomatic aperture varies with light intensity one-peakedly. When the air temperature and relative humidity are above 20℃ and 90%respectively, the variation of aperture has a significant positive correlation with light intensity. At above 20℃ and below 80% of relative humidity, no correlation between them can be found and the diurnal variation of stomatic aperture shows a two-peak changing pattern. The content of chlorophyll b in leaves is slightly higher and there is a higher absorption peak at 430 nm, showing Dendrobium in Huoshan county having the photosynthetic characteristics of shade plant.

Poplar canker caused by Phomopsis sp

Zhong Zhaokang, Zhao Min, Yuan Zhiwen, Li Lianzhi

1993, 4(1):  22-26. 

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The poplar canker caused by Phomopsis sp. is a new disease occurring on poplars in China. Two shapes of conidia are found. One is fusiform, hyaline, single-cell, 1.64—2.74×9.59—13.70μm, and another is linear with curved top, 1.37—1.78×15.00—27.40μm. The suitable growth temperature of fungus is 25-32℃, its suitable pHis 6—10, and potato dextrose agar, malt agar media and bean cake are suitable for its growth. The disease occurs in the last ten days of April, conidia matures in the second and last ten days of May, and the dispersing peak of conidia is in the second and last ten days of June. Experiments with poplar cuttings treated by carhendazim, thiopanate methyl and asomate (200-fold concentration) are carried out in laboratory. The results show that the harm of fungicides is produced on cuttings in30,60 and 90 minutes, but, a concentration of 100—200-fold is harmless in10 minutes and shows a good effectiveness for controlling the disease. An effect of 87.5% is obtained on young trees in afforested plantation when the above mentioned fungicides (100-fold) concentration are used.

Internal and external nutrient cyclings of poplar tree Ⅱ. Transferring and cycling of nutrients in and out of the tree before and after leaf fallen

Shen Shanmin, Yu Wantai, Zhang Lu, Lian Hongzhi

1993, 4(1):  27-31. 

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About two third of Nand half of Pin leaves are transferred to trunk, branch and root, but part of Kin bark and wood seems to be excreted into soil during leaf falling season. Owing to the uptake of Ca and Mg being continued and the Si in bark and wood being partly transferred to leaves is much high than that in living leaves. The gross cycling rate of Nduring the season is calculated as 62—67%, mainly from internal cycle. The corresponding figure for Pis 31—36%, with half from internal and another half from external cycle. The gross cycling rate of K, Ca,Mg and Si is about 50% respectively, almost from external cycle.

Optimum regression model of temperature-heat-wheat yield

Zhang Zhengbin, Wang Dexuan, Xu Jinxi

1993, 4(1):  32-36. 

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Through correlation analysis of temperature, heat and wheat yield in Shaanxi province, an optimum regression model of them is established. It's indicated that in less precipitation areas of this province, the yield-increasing effect of temperature and heat is not normally brought into play, but in more precipitation areas, this effect brings into paly to a certain extent. Corresponding yield-increasing measures for wheat in various areas of this province are put forward in this paper.

Role of planting grass in albic soil amelioration

Yu Deqing, Ding Qingtang, Guan Ximing, Wu Zhijie

1993, 4(1):  37-41. 

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The effect of alfalfa introduced in farmland ecosystem on soil eco-environment is studied in this paper. Experimental results show that after three years planting of alfalfa, soil aeration increases by 2.37—5.34%, soil organic Ccontent by 0.349—0.600%, average crop yield by 25%, and filtration coefficient by a factor of 1.7—6.5. The ratio output and input of planting alfalfa is 0.36—0.39times higher than planting crop alone.

Regional distribution of rice grain quality in climatic transitional regions from north to south China

Zhang Songwu

1993, 4(1):  42-46. 

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On the basis of agricultural climatic indices, the ecoclimatic factors affecting rice grain quality in regions investigated were comprehensively assessed by integrated fuzzy estimation method, and the regions were divided into areas by qualitative aggregation method. The variations of rice grain quality in all areas had the common regularity.

Spatial pattern of Echinocnemus squameus and tillage impact

Dai Zhiyi, Yang Yizhong, Huang Donglin, Huang Shoushang, Wang Chunan

1993, 4(1):  47-52. 

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Samples of Echinocnernus squameus from 36 paddy fields are analyzed to determine its population spatial pattern in terms of pattern parameters I,C_A、I_δ、m^*/m, α and β. Anegative binomial distribution with common k values is shown for both larvae and adults when the average density of adults X ≥0.6 head per quadrat (1 quadrat=0.5m²) and a complete randomness is found for adults when X <0.6 head per quadrat. The dynamics of adult patchiness, such as patch size and occupied area, seems to be related with average density. The population aggregation is influenced by environmental heterogeneity when the average density is low, but mainly determined by its own behavioral custom when the density is relatively high. The aggregation intensity of larvae population and the overwintering mortality will increase with increasing intensity of tillage.

Infectivity and effectiveness of VA mycorrhizal fungi in red soils

Wu Tiehang, Hao Wenying, Lin Xiangui, Shi Yaqin

1993, 4(1):  53-58. 

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This paper deals with the infectivity and effectiveness of VAmycorrhizal fungi in red soils derived from quarternary red clay in hilly areas of central China. Propagule number of indigenous VAMfungi in red soils under natural vegetation, planted with upland crops and suffered from erosion was 33, 50 and 2—3 per 100g soil respectively estimated by MPNmethod. Development of infection was paralleled with the population of VAMfungi in soil. There was a lag phase of infection in cultivated red soil and mycorrhizal infection was quite low throughout the whole growing period on eroded red soils. VAMinfection in both cultivated and eroded soils was promoted significantly by mycorrhizal inoculation. Proper liming and phosphorus fertilization also encouraged VAMinfection of plants on both soils, and hence the total amount of phosphorus and plant growth were greatly enhanced.

Nutritional ecophysiology of Tremella fuciformis and its associated fungus

Wang Yuwan, Wang Yun, He Xingyuan

1993, 4(1):  59-64. 

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The nutritional ecophysiology of Tremella fuciformis and its associated fungus growing on cellulosewaste is studied. The results show: 1) Tremella fuciformis grows too poor to develop fruit bodies when cultivated alone on cellulose-waste, but grows very well and produces fruit bodies normally when cultivated together its associated fungus on the same medium; 2) cellulose is the main carbon resource for two fungi during fruitification; 3) there is an enzymatic coordinating effect between the two fungi in cellulose degradation; and 4) the fruitification of Tremella fuciformis can promote cellulose degradation.

Effect of Nile tilapia on plankton community and primary productivity of freshwater microcosms

Ruan Jingrong, Rong Kewen, Wang Shaomei, Liu Quxia

1993, 4(1):  65-73. 

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In this paper, the effect of varying densities of Nile tilapia, Oreochromis niloticus,on structure and function of freshwater microcosms is studied. The results show thatthe predation of Nile tilapia induces the decrease of zooplankton density and results in the increase of phytoplankton denslty,primary productivity and P/Rratio. In the meanwhile, the transparency of water column is decreased andits pHvalue is increased, which induces the water body of freshwater microcosms becoming eutrophic in the later period of experiment. There are significant differences in plankton densities and P/Rratios among all or part of the microcosms with tilapia, but their primary productivity, final physicochemical condition and fish harvest are about the same. Therefore, the changes of community structure and metabolism in microcosms under experimental conditions are not well consistent with the predictions from trophic cascade hypothesis ,indicating that the microcosms is regulated or controlled by both predation (top-down effect and physico-chemical factors (bottom-up effect). It is inferred that if stocking greater density of Nile tilapia, the eutrophication process of natural water body under greater nutrient loading will be speeded up.

Feeding habit and seasonal variation of ingesting of left-eyed flounder in south Bohai Sea

Dou Shuozeng, Yang Jiming

1993, 4(1):  74-77. 

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Food compositions in stomachs of adult left-eyed flounder of 150—245 mm length collected from south Bohai Sea from July 1982 to July 1983 are analysed in this paper. The results show that lefteyed flounder (Paralichthys olivaceus) is a predatory fish. There are more than30 species of animals ingested by it. It feeds chiefly on fishes (e. g. Clupanodon puncatatus, Engraulis japonicus, Setipinna taty, Chaeturichthys hexanema and Cynoglossus joyneri), crustaceans (e. g. Oratosquilla oratoria, Alpheus distinguendus, Alpheus japonicus and Crangon affinis) and molluscs such as Loligo japonica. Fishes (80.9%) and crustaceans (18.6%) are ingested in spring, fishes (83.5%) and mollusca (13.1%) in summer,fishes (87.9%) in autumn and fishes (73.2%) and crustaceans (19.7%) in winter.

Effect of root exudates from Eichhornia crassipes on phenol-degrading Enterobacter sp. nov

Wu Hui, Zheng Shizhang

1993, 4(1):  78-84. 

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This paper studies the effect of root exudates and their fractions (amino acid, organic acid and reducing sugars) from Eichhornia crassipes on the growth, enzyme activity and phenol-degrading efficiency of Enterobacter sp. nov. The root exudates and their fractions at low concentrations (≤1%) show a stimulatory effect, but at high eoneentrations (≥10%), they inhibit the induction of phenol-degrading enzymes and reduce the efficiency of phenol-degradation while stimulate the growth of Enterobacter sp. nov. It is demonstrated that sugar fractions of root exudates are effective on phenoldegradation, and hence, it is possible to establish a phenol-degrading system with E. crassipes and Enterobacter sp. nov.

Single population biomass growth model under considering the dynamic equilibrium of supply and demand of nutrients

Yan Xiaodong, Zhao Shidong, Songbo

1993, 4(1):  85-88. 

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On the assumption of real single population biomass growth being resulted from dynamic equilibrium of supply and demand of nutrients, a model of single population biomass growth is developed. The model looks like Cui-Lawson's model, but its three parameters are differed from Cui-Lawson's model's biological meaning. The model can answer under which conditions some growth patterns of single population biomass appear, and can give the relation of single population biomass growth with population itself's intrinsic growth rate and decomposition condition of nutrient recycling. The establishment and interpretation of this model are audio-visual.

Mechanisms of competitive adsorption and desorption of phosphate in soil

Xia Hanping. Gao Ziqin

1993, 4(1):  89-93. 

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Research results about competitive adsorption and desorption of phosphate (P) in recent years are summerized in this paper. Many anions in soils are able to compete the adsorptive sites with P, resulting in a decrease in the amount of Padsorbed. Organic matter either promotes or inhibits Padsorption, and pHis one of the main factors affecting Padsorption. Most of Pfixed on soil surface through adsorption is hard to be desorbed, and the process of Pdesorption has an evident lagging phenomenon. Generally, only physically adsorbed Pcan be desorbed, and chemically adsorbed one forms two coordination bonds with metal cations, very hard to be desorbed by leaching. There are many factors affecting Pdesorption, one of which is the type of desorptive reagents.

Re-recognizing on ecolomical benefits of exploiting grassland resources in south China

Yang Zhongyi, Zhang Hongda

1993, 4(1):  94-98. 

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Through ecolomical comparison, this paper approaches the signficance of exploiting grassland resources on south China and its optimum way. Based on the former studies and series of calculation, it's suggested that in north China, the utilization of grassland resources should be under the prerequisite of environmental protection, and in south China, the utilization could be performed simultaneously with the latter. It's proved that theoretically, grassland in south China has the same gross primary prodictivity as in north China, but its ecological plasticity is more superior. Owing to the apparent economic benefit of forestry is limited by various factors and the forestry cannot play a major role in promoting economy of mountainous region, the optimum way of exploiting grassland resources in south China should be the combination of forestry and animal husbandry.

Mieroclimate in tea tree crown and its effect on growth, development and biochemical composition of new shoots

Huang Shoubo, Fan Xinghai, Yao Guokun

1993, 4(1):  99-101. 

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The studies show that the light intensity and leaf temperature in tea tree crown decrease gradually from peripheral to central, from top to underneath and from south side to north side. The difference of air humidity in various positions of crown is smaller, and the wind speed on windward side is greater than lee side. New shouts in south and west crown sides sprout and grow earlier than those in north and east crown sides. The number of flower buds in north and east crown sides are less than that in south and west crown sides. The amino acid contents in new shoots increase slightly from south and west to north and east crown sides, and the contents of tea polyphenol and caffeine in south and west crown sides are more than those in north and east crown sides.

Effect of high light-efficiency film on ginseng ecology

Meng Jiwu, Hou Shanggong, Yang Yuhua, Pang Bencheng, Zhou Min, Piao Yongji, Peng Yuzhen

1993, 4(1):  102-105. 

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Ecological characters of ginseng are investigated with reflection spectrum technique. The results show that there are two strong absorption bands for ginseng leaf at 440nm and 680nm, and the ultraviolet light below 380nm is reflected weakly, so the scalding of ginseng is occured Under strong sunlight. Afluorescence reagent which can convert ultraviolet light into red light is mixed into polythene films to simulate the absorption spectra of ginseng leaf, and the radiation spectra of this new film are similar to the latter. After using this new film in ginseng culture, the transmissive light quality of ginseng awning is improved and the photosynthesis of ginseng is promoted. The yield of ginseng and its quality are also increased.

Eco-genetic analysis of yolk colour of duck's egg

Chen Xiaolin, Chen Qin

1993, 4(1):  106-108. 

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The yolk eolour is controlled by genetic and nutritional factors. The heritability ot yolk eolour of Jinding duck at 200 days and 300 days of age is 0.05 and 0.22 respectively. The additions of 0.008%of Lucantin Red or 7% of Spirulina platensis powder can increase the yolk colour from 9 to 14—15 or more in the Roche score. 6% of Porphyra sp. or 6% of Laminaria sp. powders or 2% of rapeseed oil can all improve yolk pigment. In addition, the yolk colour is relative to the shell colour, but is not affected by the age.