دانلود رایگان مقاله آنالیز ساختار جمعیت Blysmus sinocompressus با نشانگر ISSR

Abstract

Blysmus sinocompressus (Cyperaceae) is an edificator and dominant wetland endemic grass of ecological and economical importance to northwestern China. Inter-simple sequence repeats (ISSR) were used to reveal the genetic diversity and population genetic structure in nine populations of B. sinocompressus in the Qilian Mountains. The genetic diversity of B. sinocompressus was high at species levels (PPBs = 74.76%, Hs = 0.1668), but relatively low at population levels (PPBp = 31.01%, Hp = 0.0941). A significant genetic differentiation (Gst = 0.4355) and low gene flow (Nm = 0.6480) were found among populations. Analysis of molecular variance (AMOVA) test revealed that 55.52% genetic variation occurred within populations and the remaining 44.48% was found among populations. Using unweighted pair-group method with arithmetic average (UPGMA) dendrogram, the nine populations were classified into three groups: (1) a single population of ZMS from Heihe River; (2) the YHLK population (Heihe River) and a subcluster of populations from Qinghai Lake; (3) the QLHH population (Heihe River) and a subcluster of populations from Daitong River. Similar results were obtained by using Principal coordinates analysis (PCoA) and Bayesian cluster analysis. Moreover, the genetic diversity of B. sinocompressus was negatively correlated with latitude, while positively correlated with annual mean temperature. With these observations, we propose a much needed conservation strategy for this plant in the Qilian Mountains.

4.3. Conservation implication

Genetic diversity is of primary importance for nature conservation and population structure is valuable for proposing conservation strategies. The low levels of genetic variation within populations and the high levels of genetic differentiation among populations of B. sinocompressus indicate that the most effective strategy for preserving genetic variation is to conserve as many populations as possible. Because the B. sinocompressus populations are highly fragmented in the Qilian Mountains, it is pivotal to preserve the natural habitats. Therefore, the first important step one must take is to reduce the disturbance by human and animal activities. For in situ conservation, preserving only one or two populations of B. sinocompressus would not achieve the goal. For example, QHHD population harbors the highest level of genetic diversity and it should be a priority for conservation. Moreover, the three populations in Heihe River should also be importantfor in situ conservation. For ex situ conservation, a carefully designed and installed germplasm bank is necessary for this species. Transferring the rhizomes from different populations to a more suitable habitat to artificially increase the gene flow should also be considered.