The Study On Resistance And Reproduction Of Four Carex Spp.

As a plant of ground-cover, Carex species have many advantages such as a wide ecological amplitude, species richness, good color and rich luster, long growth phase and strong stress resistance. Carex nemostachys, C. brunnea, C. chungii and C. tristachya are used as materials in experiment, the sdudies have been made, including investigating their field habitants, introduction and cultivation, observation of their biological and ecological characteristics, measurement of their stress resistances and reproductive characteristic. The results turned out as follows:(1) Ornamental characteristics: these four Carex species, whose leaves turn green early in the following year, are long growing time and evergreen; C. nemostachys can be used for water landscaping, which grows densely and tidily, has wide and lustrous leaves and well-developed undergroud stems. C. brunnea could be used as ground-cover and mixed lawn, whose leaves will change from viridescence to verdure then to black green in Spring. It grows in cluster, whose stems are dense, but leaves are loose with them hanging down like an arch. Its anthotaxy is longer than the frond and has full rural feeling is thicker. C. chungii is lower than C. nemostachys and C. brunnea, and its leaves are exquisite, dense and neat. Comparing with other three Carex species, C. tristachya leaves are softer and tousier. The best time for apprexiating is spring, in which the new leaves come out.(2) Shade tolerance: According to the changes of their morphological characteristics, Chl.a+b, Chl.a/b, LCP and LSP under the different shading, the comprehensive appraisal of the shade-tolerance ability has been made about six plants including four Carex species and two other reference plants (Hosta plantaginea'So Sweet'and Reineckia carnea). The order of the ability of shade-tolerance from strong to weak was: C. brunnea > Hosta plantaginea'So Sweet'> Reineckia carnea > C. nemostachys > C. tristachya > C. chungii.(3) Drought tolerance: the comprehensive appraisal of the drought-tolerance ability have been made about four Carex species, according to seven physiological and biochemical indexes: morphological index, content of holding water, relative conductivity, soluble carbohydrate content, Pro content, SOD activity, POD activity. The ability of drought-tolerance of four Carex species was in the order: C. brunnea > C. chungii > C. tristachya > C. nemostachys.(4) Cold tolerance: Taking Reineckia carnea as reference plant, comprehensive analysis of four Carex species'cold-tolerance have been given on the basis of six indexes under the stress of different low temperature: relative conductivity, semilethal temperature, soluble protein content, MDA content, SOD activity and POD activity. A conclusion has been made that the cold-tolerance of C. chungii was the best among all five species while C. tristachya was the worst, and other plants had quite similar cold-tolerance ability.(5) Reproductive characteristics: On the basis of the investigation in field and experiment of seeds germination, it showed that the seeds of C. nemostachys, C. brunnea and C. chungii have certain dormancy characteristic, which had to go through a dormant period to make a disposal and get enough time to wake them up. C. nemostachys and C. brunnea have the relatively high germination rate. For C. nemostachys seeds, the germination rate reached 69% under the disposal of 20ppm NAA in two hours and it had a big capacity of vegetative propagation in way of offshoots. For C. brunnea seeds, it also reached 60% under the disposal of NAA and the seed could keep germination and vital capacity for a long time in the sand.