Abstract: An indoor pot experiment cultivating Carex cinerascens using rhizomes to explore effects of soil moisture regime on rhizomatic germination, growth of young shoots and physiological features of the plants. The experiment, lasting 60 days, was designed to have 8 water treatments, i.e. C1(severe drought 2%), C2(10%), C3(15%), C4(20%), C5(25%), C6(30%), C7(40%, water saturation) and C8(50%, flooded with 2-cm-rhick overlying water). Result show: (1) Rhizomatic germination rate of the plant was low in Treatments C1 and C8 and reached 100% though in Treatment C2, where the young shoots were only 2/3 of those in Treatment C6, the maximum in mean plant height. Average height and aboveground biomass of the young shoots increased first and then decreased as the soil water content increased, and an exponential relationship was observed between height and biomass of the shoots; (2) Length, width, area and number of the leaves displayed a similar trend, increasing first and then decreasing as the soil water content increased except for Treatment C4. The plants adapted themselves to variation of soil water content by regulating their plant size, leaf area, number of leaves and growth rate for survival; (3) Contents of Chl a, Chl b, SPAD and Chl in young shoots also followed the same trend in variation, increasing first and then decreasing as soil water content increased, but chl a/b ratio did a reverse trend, decreasing first and then increasing as soil water content increased; The 8 treatments did not differ much in leaf water content and Car/Chl; Under water stress (too much or too little), the plants raised Chl a/b, maintained Car/Chl and rationalized distribution of Chla and Chlb, to guarantee normal photosynthesis process; (4) Quantitative analysis using the Gaussian Model shows that the ecological amplitude of water content for rhizomatic germination and growth of young shoots of Carex cinerascens was in the range of 4.15% -51.35%, and the optimum water content in the range of 16.22% -39.55%.

Key words: Carex cinerascens, soil water content, germination, young shoot growth, ecological amplitude