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Table of Content
    Volume 19 Issue 1
    10 January 1995
      
    Research Articles
    A Preliminary Study on the Formation of Saline-Alkali Plant Communities in the Song-Nen Plain
    Zheng Hui-ying, Li Jian-dong
    Chin J Plan Ecolo. 1995, 19 (1):  1-12. 
    Abstract ( 2068 )   PDF (670KB) ( 630 )   Save
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    The results of our investigations and analyses have shown that topographical, geomorphologic, hydrological, climatic and pedological conditions in the Song-Nen Plain all have potential effects on the formation of saline-alkali plant communities. Human activities such as overgrazing could bring about the degradation of Aneurolepidium chinenses grassland, as indicated by the appearance of saline-alkali plant communities. During the formation of saline-alkali plant communities, the species composition and population dynamics of the original community will change. The changes of the soil properties include salt content and the composition of salt ions, pH, soil organic matter content and its associated properties. Finally, the saline-alkali plant species reach an dynamic equilibrium with their habitats. Weighted average index and community coefficient were employed as quantitative indices to quantify the changes of vegetation characteristics during the formation of saline-alkali plant communities.
    Characteristics of Element Contents in Plant Species of the Karakorum and Kunlun Mountains
    Kong Ling-shao, Li Bo-sheng, Guo Ke, Ma Mao-hua
    Chin J Plan Ecolo. 1995, 19 (1):  13-22. 
    Abstract ( 1989 )   PDF (565KB) ( 636 )   Save
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    We discussed the characteristics of the contents of 12 elements (K, Na, Ca,Mg, Ba, Sr, Be, Fe, V, Ti, Mn, Al) in 87 plant species collected from Karakorum and Kunlun Mountains. The average contents of K and Ca were higher than 10000 ppm; Na, Mg, Fe and Al ranged between 800 and 5000 ppm;V and Be were less than 10 ppm. The Fe, V and Be contents in the plants were higher than the average of the terrestrial plants. The K contents in different plant species showed a pattern of normal distribution. while other elements tended to represent lognormal distributions. Plant species differed greatly in the contents of the elements. indicated by using the coefficient of variation (C.V. %). Na had the highest C.V. among species. while K and Ca had the lowest. The same plant species collected from different habitats also demonstrated great difference so did the different plant species for instance, Stipa purpurea>Ceratoides compacta>Saussurea gnaphaloides. The analysis of correlations between elements in different plant species indicated that the correlations between Al and V, Fe and V, Ti and Al et al., were statistically significant. The classification and ordination of the 22 plant species using TWINSPAN and DCA methods suggest that these plant species can be classified as Na and K type plants. and Fe, V, Al and Ba type plants, respectively, based on the contents of 12 elements in the plant tissue.
    Studies on the Feasibility of SOD Activity as Bioindicators of SO2 Pollution
    Chen Xiao-yong, Song Yong-chang
    Chin J Plan Ecolo. 1995, 19 (1):  23-28. 
    Abstract ( 2040 )   PDF (368KB) ( 626 )   Save
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    Fumigation and ambient exposing experiments were conducted to evaluate the feasibility of using SOD activity in the leaves of broadbean (Vicia faba) as bioindicators of SO2 pollution. Fumigation experiments were conducted in dynamic fumigation systems with SO2 concentrations of 0.1312 and 0.2601mg·m-3, respectively. The SO2 fumigated leaves had higher SOD activities than the control, and higher concentration (0.2601 mg·m-3) of SO2 caused greater increase in SOD activity than lower concentration (0.1312mg· m-3). The SOD activity in SO2 fumigated leaves increased gradually at the beginning and reached a relatively stable stage after several days of treatment. Ambient exposing experiments were conducted with the form of plant- meter in 8 sites for 21 days. The SOD activity correlated significantly with the rate of sulfatization (RS) in the air at the level of p<0.01. The degrees of SO2 pollution at sample sites were evaluated with SOD activity and RS respectively. RSs were also estimated by SOD activity, and then compared with the actually detected values. The 95% confidence interval was also made. All of our results suggest that it is feasible to use SOD activity in the broadbean leaves as bioindicators for SO2 pollution.
    Weibull D. B. H. Distributions and Their Dynamic Predictions in the Natural Uneven-Aged Evergreen Broad-leaf Juvenile Forest
    Hong Li-xing, Du Guo-jian, Zhang Qing-rong, Liu Ben-tong
    Chin J Plan Ecolo. 1995, 19 (1):  29-42. 
    Abstract ( 2028 )   PDF (702KB) ( 742 )   Save
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    Evergreen forest is the natural vegetation in the eastern part of subtropical zone of China. This study area was in the northwestern part of Zhejiang Province where the dominant tree species based on 44 sample plots were Cyclobalanopsis glauca, Lithocarpus glaber, Castanopsis eyrei, Schima superba, Castanopsis sclerophylla and so on. The Weibull fuctiion could flexibly express the D.B.H. distributions of the evergreen broan-leaf forest with varied skew and kurtosis distributions. With the increase of stand diameter (D), the D.B.H. distributions of the evergreen broad-leaf forest could be expressed by curves that changed from exponential to inverse-J, and finally to normal shapes. The skew degrees tended to change from positive to negative, and kurtosis degreased gradually with an accompanying increase in the modes. Using parameter estimation methods, the models and schedules, in which D was used as independent variable, of the dynamic D. B.H. distributions of the natural uneven-aged evergreen broad-leaf forest were established. These models can be used for the reasonable management of forest resources.
    Horizontal and Vertical Fluctuation of Number and Longevity of Leaf Populations in Henry Pine (Pinus henryi) Forest
    Xiao Yu
    Chin J Plan Ecolo. 1995, 19 (1):  43-54. 
    Abstract ( 1586 )   PDF (715KB) ( 768 )   Save
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    I analyzed the horizontal and vertical dynamic characteristics, fluctuating trends and the demography of leaf populations of Henry pine stands, and obtained the following results:(1) The leaf number per tree and number of leaves of varying ages increased with stem diameter, but decreased with stand density. The percentage of current-year leaves increased with stem diameter, but the opposite was true for 2-year-old leaves. The ratio of 1-year-old leaves to 3-year-old leaves kept stable.(2) The stem diameter was negatively correlated to the leaf life expectancy. The lire expectancy of the leaves in the inferior trees were the shortest, and the average trees the longest, while the dominant trees fell in between.(3) Generally, the number of leaves of varying age classes was highest in the middle part of the canopy, but difference existed in the structure of leaf populations among tree types. This could be ascribed to the light conditions in the canopy.(4) The intrinsic rate of increase of the leaf populations increased with stem diameter, tree height and relative light intensity in the canopy. The life expectancy of leaves in different branch cohorts decreased with tree height. It was inferred that the life expectancy of leaves in the same branch cohort would increase with branch age.
    Study on the Population Ecology and Control of Ascendent Crab Grass in Summer Grain Crops in Hebei Province
    Lü De-zi, Bai Su-e, Li Xiang-ju, Wang Gui-qi
    Chin J Plan Ecolo. 1995, 19 (1):  55-63. 
    Abstract ( 2026 )   PDF (529KB) ( 1144 )   Save
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    Studies indicate that crab grass has a growth period of 62—111 days and needs>0℃ accumulated temperature of 1380℃–2176℃. Grab grass has a strict demands on season and temperature at vegetative stage, but is insensitive to these conditions at reproductive stage. The length of growth period is mainly determined by that of the vegetative growth stage.Seed storage conditions have great bearings on the maintenance and release of seed dormancy. The release of seed dormancy is fastest under storage conditions of constant temperature.The minimum temperature for seed germination is 15℃. The effective accumulated temperature for the germination of 60% of the seeds is 555.13℃. The relationship between seed germination rate(y) and temperature(x) can be described by the following formula: y = - 103.722 + 15.133x- 0.288x2. The germination of seeds is insensitive to light. The results showed that the seeds buried to a depth of 7 cm generally emerged, and the maximum emergence rate occurred for the seeds buried in the depths of 1—4cm.Crab grass has a great reproductive capacity. Our results showed that almost all cutting nodals with fibrous roots and buds could develop to new plants with the exception of ear stems.The results of path analysis indicate that crab grass is a main weed for summer grain crops in Hebei Province. The relationship between the loss of crop yield(y, %)and the density(x,Plants/m2)of crab grasses could be expressed by the formula: y = 0.1532xl.5574(x≤20Plants/m2),or y = - 18.400 + 11.315lnx (x>20 Plants/m2). And the relationship between the loss of crop yield(y, %)and the days of coexistence(x) of crab grass with summer corn was formulated as: y=54.5956/ 1 + 89.7962e-0.1184x Based on our calculations, the critical density for crab grass in summer corn field in Shijiazhuang region is 5.8 Plants/m2.
    Biocycling of Nine Nutrient Elements in Winter Wheat on a Calcareous Alluvial Soil From Beijing
    Chen Ming, Tan Jian-an, Yin Chong-ren, Zhu Li-hui
    Chin J Plan Ecolo. 1995, 19 (1):  64-71. 
    Abstract ( 2109 )   PDF (555KB) ( 703 )   Save
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    In this paper, we report the results of a series of greenhouse pot experiments designed to investigate the biocycling of nine mineral elements in winter wheat on a calcareous alluvial soil collected from Beijing region, The results showed that there were significant differences among the quantities and rations amount returned to the soil. We grouped these nutrient elements into three types in accordance with the percentages of output by plants and the amount returned to the soil:1) The type of low returning and high output rates included N, P and K, which generally had returning rate of less than 20% and output rate of greater than 60%.2) The type of high returning and low output rates was composed of Ca and Fe, which had returning rate of greater than 50% and output rate of less than 10%.3) The type of moderate returning and moderate output rates consisted of Mg, Mn, Cu and Zn, which had returning rate falling between 30—50%, and outpualling betling between 20—30%.The total uptake of N an Mn by winter wheat plants and the output or removal of K by grains generally increased due to the application of Mn fertilizers. While the total uptake of Mn by plants decreased with the application of Zn fertilizer. The effects of Mn and Zn fertilizers on the biocyclings of some nutrient elements in winter wheat on a calcareous alluvial soil in Beijing region were quite antagonistic.
    A Comparative Study of Photosynthetic Response of Kobresia humilis to Different Environmental Factors
    Lu Cun-fu, Ben Gui-ying, Han Fa, Shi Sheng-bo
    Chin J Plan Ecolo. 1995, 19 (1):  72-78. 
    Abstract ( 2026 )   PDF (455KB) ( 1229 )   Save
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    The photosynthesis and its response of Kobresia humilis, which were obtained from different altitudes in Qinghai Plateau, to the glowing environmental conditions and cold stress were studied. The results showed that the chlorophyll content in the K. humilis leaves tended to decrease with increasing altitude, but the chlorophyll a to b ratio and the carotenoid content increased. The photosynthetic rate, light compensation point and light saturation point increased with the increase of altitude, and the photorespiration rate declined. The photosynthetic apparent quantum yield of K. humilis grown in the culture room (PAR: 60—70 μmol·m-2·s-1 mean day/night temperature: 15℃/10℃) was higher than that grown in the green house (PAR. highest 1250 μmol·m-2·s-1; mean day/night temperature: 24℃/13℃), whereas the photosynthetic rate and Hill Reaction rate were the opposite. The optimum photosynthetic temperature varied with the growing temperatures and the original growing altitudes. The photosynthetic rate and apparent quantum yield of K. humilis decreased after being subjected to cold stress. The cold stress was more inhibitive to the photosynthetic rate under light (90—100 μmol·m-2· s-1) than under dark conditions.
    A Preliminary Palynological Study of the Surface Soils of Modern Vegetation in the Zijin MT., Nanjing
    Yu Ge, Han Hui-you
    Chin J Plan Ecolo. 1995, 19 (1):  79-84. 
    Abstract ( 1793 )   PDF (355KB) ( 786 )   Save
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    We surveyed the modern vegetation in the Zijin MT. Nanjin, and conducted pollen analysis of the surface soils. Combining pollen analysis data of the surface soil samples from some sites of the eastern part of China, we compared the percentage, composition,dominant and indicator species of the pollens with our results of vegetatiom surveys. The relationship between pollens and vegetation types was revealed. Our results will provide important information for the study of Quaternary palynology and for the improvement of research on the paleovegetation and paleoclimate.
    The Ecology of Four Ephemeral Plants
    Pan Wei-bin, Huang Pei-you
    Chin J Plan Ecolo. 1995, 19 (1):  85-91. 
    Abstract ( 1990 )   PDF (442KB) ( 792 )   Save
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    Malcolmia scorpioides, Tetracme quadricornis, T. recurvata and Lappula semiglabra are common ephemeral plants in the desert of the northern part of the Xinjiang Uilgur Autonomous Region, China. Their biological characteristics such as seed biology, morphology and developmental rhythm make them adapt to the temperate arid environment.(1) Low daily maximum temperature is necessary for germination. Consequently, the seeds avoid germinating in the hot and dry summer, but germinate in the spring and autumn when there are suitable conditions for plants.(2) There are multiple germination periods during spring and autumn, with only a portion of the seeds from the seed bank germinating each time. Therefore, these plants can survive and propagate after certain catastrophic events, which can occur easily in the desert.(3) The shift from vegetative stage to reproductive stage is apparently affected by temperature. The termination of the individual’s life span depends on the soil moisture contents. This might suggest that the growth of these ephemeral plants would resemble the annuals or winter annuals if the soil moisture condition were appropriate for the growth of these plants in the summer.(4) There are two groups of individuals in one population, namely, spring-germinated plants and autumn germinated plants. They differ from each other in many aspects, such as morphology, biorhythm and reproduction rate.(5) with the active growth of plants, the spatial distributions of roots, assimilative organs and reproductive organs change with the changing environment.
    A Preliminary Study on the Vegetation of Beita Mountain, Xinjiang
    Lou An-ru
    Chin J Plan Ecolo. 1995, 19 (1):  92-99. 
    Abstract ( 1857 )   PDF (559KB) ( 877 )   Save
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    This paper reports the results of a detailed study on the vegetation types of the Beita Mountain, Xinjiang Uigur Autonomous Region bordering China and Mongolia. A comparison was made between the characteristics of the vegetation of the Beita Mountain and of the surrounding areas in the light of the horizontal and vertical distributions, and the floral elements. It was found that the vegetation of the Beita Mountain showed apparent characteristics that could be seen in the transitional zones and arid areas.The main vertical zonal vegetation types could be categorized into desert, mountain desert steppe mountain shrub steppe mountain steppe and Kobresia alpine meadow. Meanwhile the vegetation characteristics and the current status of the vegetation utilization were discussed. This study will be conducive to the understanding of the vegetation in the Beita Mountain that is situated on the west of the Junggar Basin, where the vegetation has been seldom explored. This study is also of significance for the utilization of grassland resources and the protection of wildlife.

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