| Dendrocalamus sinicus Chia et J. L. Sun, also known as crooked-foot dragon bamboo, is a perennial woody species distributed in some area in southern and southwestern of Yunnan province. And it is the world’s largest known species of bamboo with high economic value and ethnic minorities culture protection value. There are mainly two kind of stable variant of the straight-culmed and bending-culmed in original distribution zone. This article aims to make a comprehensive survey about resources situation of Dendrocalamus sinicus and preliminarily investigates the genetic diversity, genetic structure and reveal the phylogeography of this species by using the study of molecular phylogeography, then provides genetic scientific basis for resources conservation and utilization about Dendrocalamus sinicus.The results showed that D. sinicus is narrowly distributed in southweatern Yunnan, with the central distribution locates in the lower and medium mountain areas at the altitude of1000～1500m above sea level in Cangyuan, Ximeng and Menglian Counties, ranging in22°09’～23°30’N,98°56’～99～37’E. Meanwhile, from south to north within distributions, the culm type of D. sinicus shows an obvious trend as from bending-culmed, mixed type, to straight-culmed. The average diameter at the breast height is significantly and positively correlated with the altitude of populations. Sporadic flowering of D. sinicus was observed in the wild, especially for the straight-culmed type, while seed setting was rare, and the seed setting rates were as low as from0.34%to0.64%, which may be mainly due to sporadic flowering of individual culms or clumps and protogynous flowers. Apis ceranaFabricius may be one of important pollinators of D. sinicus.Through the comparing of primers, trnG-trnT region which is target and sites in noncoding region of the chloroplasts gene has the most variable sites, and its length is1149bp. Using the chloroplast trnG-trnT DNA fragment,in this study, we sampled226individuals from18natural populations of Dendrocalamus sinicus representing its distribution in Yunnan and identified nine haplotypes and ten populations with single haplotype. The inference of haplotype relationships and network analysis together showed that:(1)haplotypes linked to a ring structure generally;(2) haplotype H1is widely distributed;(3) haplotype H3which may be the most original haplotype is a private haplotype in the WQ group. Dendrocalamus latiflorus Munro is out-group. Neighbor-Joining tree (NJ) of9cpDNA haplotypes for Dendrocalamus sinicus Chia et J.L.Sun can be divided into two main branches, included in the HS group H2, H4, and H5together in one, and H1, H3, H6, H7, H8, H9together in another one. The mismatch distribution analysis and neutrality tests of Dendrocalamus sinicus Chia et J.L.Sun at the level of species show that Mismatch distribution curve is a bimodal curve, indicating that the populations is in a stable dynamic balance state in history. The number of Fu’s Fs and Tajima’s D are not significant, explaining this species in overall level didn’t encounter a bottleneck or rapid expansion. And it supports the results.According to the characteristics of Dendrocalamus sinicus culm shape type, populations are divided into three groups——the straight-culmed group (TZ), bending-culmed group (WQ) and mixed group (HS). Genetic diversity analysis showed that Dendrocalamus sinicus has high genetic diversity(HT=0.523,π=0.00366) at species level with a obvious genetic differentiation among populations (GST=0.746, NST=0.729). The structure of genetic variation is that49.56%genetic variation is existed among groups, and42.18%is located within populations, while merely8.26%genetic variation presented among populations within groups, indicating an obvious genetic differentiation among groups and within the populations。 It is likely that high levels of genetic diversity came from rich culm’s variation. The exiting genetic structure may be due to genetic drift and inbreeding adversity caused by the narrow distribution area, the scarcity of seed sources, flowering characteristics (sporadic flowering, setting low) and groups broken, besides it is also caused by human factors such as introduction and cultivation. |
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