Study On Reproductive Characteristics Of Carex Lasiocarpa

Carex lasiocarpa with elegant shape,is good resource of wet ornamental grass,which can be exploited for urban water greening.It is the main dominant species in the areas of the Sanjiang Plain wetlands.In addition,as excellent resources of fiber and forage,it has a high economic value.In this paper,we selected four Carex lasiocarpa populations of natural habitats on different water levels,clonal growth characteristics,the number of reproductive ramets,seed dormancy and germination characteristics of Carex lasiocarpa species in different habitats were systematically studied,and the major research findings are as follows:(1) Carex lasiocarpa is of more typical clone plants,which having short rhizomes and long rhizomes that can be clearly divided.The growth characteristics of its short rhizomes tend to be Phalanx-type,and long rhizomes tend to Guerrilla-type.(2) With the water level rising,the internodes length of short rhizomes showed a shorter tendency,of whose spacer length showed a longer trend,but just the reverse was the long rhizomes;the ramet's density of species showed a decline tendency,and the ramet's height gradually increased.Under different conditions,clonal architecture and ramets population characteristics of Carex lasiocarpa showed phenotypic plasticity.(3) The mean ripening rates of Carex lasiocarpa species in different habitats were all lower than 50%.The quantity characteristics of reproductive tillers showed phenotypic plasticity per height class in every Carex lasiocarpa population,and among different populations,of which, phenotypic plasticity of ripening rates is largest,female small panicles per tiller is smallest.All the biomasses variability of different height classes in any population is generally greater than which of different populations in different habitats.The ecological plasticity of seed biomass among different populations is the greatest,stem and leaf and whole-plant biomass the second, spike biomass the smallest.The reproductive allocations at two levels are both low,and phenotypic plasticity of Reproductive allocationsâ…¡is greater than Reproductive allocationsâ… .(4) The heading rate of Carex lasiocarpa populations in different habitats are all low,and showing a tendency of rising with water levels rising.External morphological characteristics of seeds in different habitats have no marked differences.The mean 1000-seedweight is 1.214±0.211g,and the seed moisture content is 10.40%,which both showed significant differences among different populations.(5) The seed viability of Carex lasiocarpa is 83%,the embryo form of majority of seeds was growth completely when the seeds harvest,seed dormancy was not due to embryo morphology.The seed-bags and seeds of Carex lasiocarpa existed germination inhibitors, which can dissolve in water,easier to dissolve in organic solvents.(6) Carex lasiocarpa seeds germinated better in variable-temperatures than in an even temperature,30/20℃is more appropriate.Soaking treatment by 2%KNO₃ solution stimulated the seeds germination to a certain extent,but unfortunate.Soaking treatment by 10%NaOH was basically broken seeds dormancy,soaking for 60 minutes is the best,that germination rate improved to 70.00%.