According to the measurement of the above-ground biomass of tropical mountain rain forests (original and regenerative forests) in Jianfengling, Hainan Island, the biomass of the two communities are up to 645.2 and 272.9t/ha(including litter biomass), the tree biomass are 96.9% and 94.0% of the totals, and the LAI values are as high as 16.70 and 9.07, respectively. Although the under-growth, liana, eiyphyte and parastic plants have high diversity, the biomass are less than 5% of the total. Comparision study show the original and regenerative forests have obvious differences in the total biomass, the distribution of the biomass in community layers and tree DBH classes. The regenerative forest dominated with Castanopsis fissa has higher productivity in the early stage. A 26-year-old regenerative forest’s average annual net biomass accumulation is up to 9. 8658 t/ha·a, which is close to that of the tropical plantations with middle-level management, and is one and a half times of that of the original mountain rain forest in Jianfengling.

Detrended correspendence analysis (DCA)and two way indicator species analysis (TWlNSPAN) are adopted for ordination and classification of montane coniferous forests in warm-temperate region. Two methods gave similar results. The data from 120 meteorological station in the warm temperate region of China are sued to get the multiple regression for estimating the climatic information of various coniferous forests using longitude, latitude and altitude as predictors. Platycladus orientalis forest and Pinus tebulaeformis forests in the low mountains are forests those can tolerante drier habitat. Actually, Pinus tabulaeformis widespreads from low to mid-montane belts, this kind of Pinus can constitutes different mixed forests with other coniferous and broadleaved trees. Pinus armandii forest adapts warm and moist site. The subalpine forests dominated by Larix principis-rupprechtii, Picea meyeri, P. wilsonii occur in the cold and moist habitat. The environmental interpretation of coniferous forests are mentioned.

Reed plant (Phragmites communis)are perennial grasses growing in swamp, salt meadow and sand dune in the Hexi Corridor, Gansu province. Salt meadow-reed and sand dune-reed are capable of tolerating dehydration caused by water stress. The activities of catalase (CAT), peroxidase (POD) and superroxide dismutase (SOD) being related to dehydration tolerance of plants were determined. The results showed that the SOD activity in leaves of sand dunereed is the highest, in salt meadow-reed comes second, in swampreed is the minimum. However, the activities of CAT and POD in leaves of swamp- reed is higher than that in leaves of other habitat reeds. The isozyme made up of CAT, POD and SOD from leaves of different habitat reed were analyzed by polyacrylamide gel electrophoresis. The SOD from leaves of salt meadow- reed and sand dune-reed compared with swamp-reed, have no variation in isozyme patterns. However, differences were observed in the different habitat reed. CAT and POD from leaves of swamp-reed have 7 band and 6 bands, respectively. Sand dune-reed has 10 CAT bands and 9 POD bands, salt meadow-reed has 9 CAT bands and 8 POD bands. These results demonstrated that the dehydration tolerance of reed plants may be attributed to enzyme polymorphismus being controlled by gene.

This study was carried out at a seabeach salt marsh in Donghai Farm, Nanhui county, Shanghai. Population density, height growth and biomass of Scipus mariquetep, as well as the interrelationships between them and with the environmental conditions, were described. The research results showed that at the relatively stable habitats(zone A and B), the population density, height growth and biomass dynamics during the growing season was in accodance with logistic growth. Three phases could be recognized for the population density and biomass dynamics, and the-3/2 power law of natural thinning was applicable to the populations in phase Ⅱ. Zone B was the optimum area for population growth of Scirpus mariqueter. The habitat conditions at the zone C were quite unstable and the population density and biomass dynamics was fluctuated drastically. Under different environmental conditions, the relative roles of density-independent and density-dependent factors on population dynamics differed greatly. At the relative stable habitats(zones A and B), the density-dependent factors were the major factors to determine population dynamics, while at the unstable habitat (zone C), the density-independent factors were the major factors.

The changes of main water parameters(MWP),including φ8sat (maximum osmotic potential at water saturation point), φ8tlp (osmotic potential when a plasmolysis just emerges), Ftlp (relative content of osmotic water), RWCtlp(relative water content)and AWC(relative water content in apoplast),in Pinus tablaeformis with season and provenance were studied by means of pressure-volume curve The result showed that the MWP in P-V curve of P. tablaeformis changed in response to the changes of both the growth and development stages and the environmental conditions. Among these parameters,φ8sat , φ8tlp Ftlpand RWCtlp were the highest during the stage of a growth peak in summer,then reduced gradually, and reached down to the lowest in cold winter. These parameters increased again when spring comes. However, the change trend of AWC was the opposite. Changes in MWP of P. tablaeformis with season were rather consistent with tree’s cold hardening. The difference in MWP of P. tablaeformis from different porvenances was remarkable, especially in winter. The synthetical index calculated from MWP indicated that of the climatic ecotypes of P. tablaeformis drought resistance had following order from strong to weak:northeast,central, east,southwest, northwest, centralwest and south type.

On the basis of the data collected from observations in 6 years,according to the principle of turbulent despersion, the basic characteristics of evapotranspiration in Chinese fir plantation was studied. Results showed that the annual evapotranspiration is 875.45mm, which takes 82.2% of the precipitation. The annual crown-evapotranspiration is 89.3% of the total evapotranspiration (781.77mm), the ground evaporation is 10.7% of total evapotranspiration (93.68mm). The total evapotranspiration increased by 1.2% compared with the results from water balance method. We also analyzed and discussed the application of turbulent flow method and its parameter estimetion.

In the temperate deserts, the snow nearest a plant melts at first then the snow around it follows. And as the water flow passage to soil appears, which centres at the plant and collects the snowmelt to water the plant, the depth of the wet sands is increased.Data on sampling area indicates that the sand moisture around the plants incresses obviously: the amount of snowmelt collected by the plant root zone is 56.77mm, which is 228.9% of the snowmelt received by bare area. The utilization efficiency of snowmelt for desert plants is improved as the moisture moved from upper soil layer to deep soil. As a result, the distribution pattern of desert plants is arranged.

The growth pattern of early spring plants near Urumqi and their relation with the local water and energy suppy and other ecological conditions were observed and studied. The results provides scientific guidence for efficient utilization and management of these plants resources in light of their unique characteristics of early genii nation and turning green and quick development.

Suaeda heteroptera is an annual herb of Chenopodieceae which is the most tolerant to alkali. According to the investigated data of random sampling in single species community, density dependence of the characters of natural S. heteroptera population alkalization meadow in the Songnen Plain of China were analysed. The results showed that the models of density dependence in different growth stages and on different quantitative characters of the population could be more presented by many functional forms. But in this paper, the model of density dependence of a certain attribute of the population were represented by the best correlation equation among the functions. The density dependence of the population showed that function form was the hyperbola function y= a+b/x for both mean weight per plant in the booting stage and fruits weight per unit area; that the power function y=ax-b was for mea weight per plant in the ripening stage, mean weight of fruits per plant, mean number of seeds per plant and seeds number per unit areas; and that the hyperbola function y= 1/(a + bx) is appropriate for above-ground biomass of the population in the booting stage and the logarithmic function y = a-b In x in the ripening stage.

The present study was carried out during 1989—1990 in high yield summer corn field. The results were as follows:Diural course of canopy apparent photosynthesis (CAP) rate was a unimedal curve(11:00—12:00). The relationship between light intensity and CAP rate showed rectangular hyperbola. The light compensition point of CAP was about 4000 Lx. No light saturation point observed under field condition. CAP increased with CO2 concentration from 50 to 900ppm. The ratio of CO2 assimilated to that released from the soil was 11.68% througout growth period. Photosynthetic rate of ear leaf was higher than the sixth leaf and the leaf next to the top leaf when leaf was expose fully to light, but there was no difference among cultivares and plant densities. Leaf photosynthetic rate was in the order of top leaves>middle leaves>base leaves under natural state and vertical leaf type cultivar>horizonal under high density condition.

Water quality of rainfall changes greatly after passing through trees canopy in the watershed. In this paper, an artificial pinus forest has been chosen to measure the precipitation inside and outside of forest, stemflow as well as the variations of their chemical contens. By analysing the characteristics of rainfall partitioning, the patterns of chemicals migrations in the field have been discussed.The results showed that the concentrations of TP, TN, Ca, Mg, Na and K were different among rainfall, throughfall and stemflow. In accordance with the rainfall partitioning, chemicals entered the field both as point source and area source, from which two different processes of motion were found. The chemical contributions in the field by rainfall and leaching from the tree was also discussed.