Study On Growing And Reproductive Traits Of Polygonum Capitatum Under Different Environmental Conditions

By constantly adjusting its morphology, physiology and behavior and so on, the plants in the heterogeneous habitats, can form their own particular traits, such as different patterns of biomass allocation and resources allocation patterns, in response to its environment. And the plants can form different adaptive changes, including genetic variation and morphological changes in different environments, to utilize resources effectivly and optimize its structures and functions.Polygonum capitatum Buch.-Ham. ex D. Don is a perennial herb, as the research object in this thesis. The experimental materials from four populations of Jinyun mountain in Chongqing, were respectively selected from the habitats in the sunny slopes of sandstone, yellow loam, humus soil on rocky surface, and yellow sandy soil (in turns as the population A, B, C, D). Firstly, the biomass and branching pattern of Polygonum capitatum collected from 4 field populations were studied. Secondly, the growth and reproductive traits of Polygonum capitatum in different treatments were studied through cultivation experiment under the control condition. And the main contents and results of the research are as follows:(1) The biomass and branching pattern of Polygonum capitatum collected from 4 populations were studied in field. And the results showed that biomass and biomass allocation of Polygonum capitatum from different populations were different. The biomass of population A is 62% of population B, but its coverage is 95.7% of population B. The branch level and the maximum length and coefficient of variation of population A are more than others'in the four populations. It indicated that Population A had a strong spatial expansion ability; Population B grew lively, showing in that the branch stem ratios of Polygonum capitatum from population B are the lowest, but the stepwise bifurcation ratios of it are the highest; Population C has larger adventitious roots investment (The adventitious roots investment of Population C is 23.67%, but they are less than 5% of other populations.), as the results of adpating heterogeneous habitats, especially soil thickness, but it is not obvious in homogeneous garden planting; Population D presented small and closely structure in response to light intensity in wild habitat.(2) For 4 populations in field, the relative biomass of stem of Polygonum capitatum in the first branch level is largest, but the relative investment of leaf and fruit in the second branch level both are both largest. Among branch levels, there are a clear division of work. The second branch level mainly invested in leaves, but first branch level mainly invested concentrated resources in stems, in order to spatial expansion. Each branch level of Polygonum capitatum from field populations has different division of labor and coordination with each other as a function integration.(3) By cultivation experiment, the growth and reproductive traits of Polygonum capitatum from 4 populations were studied under different treatments of fertilization, irrigation or shading conditions. And the results showed that the population of Polygonum capitatum from yellow sandy soil habitat grew best when they were under the treatment of irrigation, fertilization and at full-light.The combination of irrigation and fertilizer had positive effects on its growth, while shading had an obvious negative impact on its reproduction.(4) The traits of branching intensity and length of spacers of Polygonum capitatum are significantly different from populations in the different treatment conditions. It showed larger branch intensity with fertilization conditions, while it has larger spacer length without fertilization conditions. Through morphological regulation of this kind of "selective placement" formation, Polygonum capitatum place into superior environment in response to patchiness of resources, and ultimately realize the effective utilization of resources.(5) The growth dynamics, morphology and biomass effects of Polygonum capitatum clones were researched under six different controlled conditions of water and fertilizer. We found that the total biomass of population D was the largest in the sufficient water and fertilizer condition; Soil moisture and fertility conditions have close relations with the growth of Polygonum capitatum, and good water conditions has obvious synergy effect on the growth with fertilizer (F water=10.0190.000, F fertility=9.7000.003, F waterxfertility=7.8240.000)...