| The paper studied the growth of endangered plant Changium smyrnioides Wolff and its comparison plant Anthriscus sylvestri (L.) Hoffm and Chuanminshen violacewn in different soil water from physioecology and analyzed the effect resulted of soil water and the difference of model and size of plasticity of three species.The experiment was developed in arboretum of Zhejiang University. And plants are one year old and two year old of the three plants. We set up three soil water treatments: the first was saturation treatment, that is, relative water capacity (RWC) of soil approached water holding capacity (WHC) and keep in 90%-100%, dipped in water to make it renew saturation when RWC depress to 90%. Same to the second treatment (moderate treatment, RWC:50%-100%) and the third treatment (drought treatment, RWC:20%-100%). We observed the plants at intervals and harvested them at different growth season to carry out growth analysis. The result summarized as follows:1. Height, crown amplitude, size of leaves, leaf number, diameter of root, biomass of leave, biomass of root, total biomass and relative growth rate (RGR) of C. smyrnioides were all increase with soil water. But it was decreased with soil water for specific leaf area (SLA), leaf area ratio (LAR), specific root length (SRL) and root length ratio (RLR). C. smyrnioides would allocate more biomass to root for store with growing. The ratio of biomass stored in root of two year old plant was more than one year old, and drought than saturation, the last period of growth than start period.2. All the corresponding parameters of A. sylvestris were similar with C. smyrnioides in procreate period in April. But the parameters of root length, diameter of root, volume of root, leaf biomass, root biomass, total biomass, root mass ratio (RMR) and SLA had the maximal value in moderate treatment in vegetative period in January. The ratio of the root mass of two year old A. sylvestris was more than one year old, and drought than saturation.3. For C. violaceum, it is moderate treatment that all the corresponding parameters have the maximal value. But it still was maximal for leaf biomass, LAR, ramose number of stem, stem biomass and umbrella number of flower. And the RGR of drought treatment in January exceeded the saturation treatment largely, but the difference among treatments was small in April.4. Height, crown amplitude, size of leaves and leaf number of A. sylvestris were the largest among three species, and C. smyrnioides's were the lest. But it was C. smyrnioides that had theæ°”largest RMR, SRL, RLR and RGR, and it was C. violaceum that had the minimal value. Biomass of leaf, root and total plant were always maximal for C. violaceum and minimal for C. smyrnioides. For SLA, it is A. sylvestris and C. violaceum that had the maximal and minimal value respectively among the three species. The leaves biomass, root biomass, total biomass, SLA, LAR, SRL, RLR and RGR of three species had very obvious plasticity to soil water. But the plasticity degree of three plants to different soil water were C. smyrnioides> A. sylvestris > C. violaceum. And the plasticity of height, crown amplitude, leaves morphology, leaf number, allocation of biomass (including: LMR, RMR and shoot/root ratio) and LAR were low to soil water for all three species.5. The leaves of C. smyrnioides had been yellow in the end of April and the overground part of the plant had been blasted in the first of May. But at the same time, it just turned yellow for saturation treatment. And A. sylvestris and C. violaceum have similar tendency, that is, the plant in drought treatment blasted earlier than in saturation treatment.6. The time and the devotion of procreate of three species are both influenced by soil water. It is possible for three year old flourish plant of C. smyrnioide to flowering. It is later more for the plants stressed by drought. For A. sylvestris, it is usually the second year that plant flower and procreate and company with clone. The time of procreate would be delayed for...
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