天山北部拟南芥生存群落特征及其与环境的关系

Community characteristics of Arabidopsis thaliana natural populations in the northern Tianshan Mountains along with relevant environmental factors

为了解拟南芥在天山北部的分布状况及环境依赖特点,分析拟南芥的自然选择特征,本文对天山北部分布的13个拟南芥(Arabidopsis thaliana)生存群落结构、组成及其与环境关系进行了研究,并分析了拟南芥与群落主要物种的种间联结性。结果表明:拟南芥生存的群落结构简单,其中天山北坡中段的石河子、一四三团、沙湾、独山子地区的8个群落均为草本类型,优势种相似,而与伊犁果子沟、额敏和阿勒泰的5个群落差别较大。属的区系成分分析表明世界分布、北温带分布以及地中海、西亚至中亚分布型成分占大多数,具有典型的地中海旱生植物区系分布特征,体现了本地拟南芥分布及演化的干旱、半干旱的地理环境特点。采用双向指示种分析(TWINSPAN)将13个群落分为新疆绢蒿-猪毛菜-角果毛茛(Seriphidium kaschgaricum-Salsola collina-Ceratocephalus testicula-tus)、新疆绢蒿-猪毛菜(S.kaschgaricum-S.collina)、新疆绢蒿-狭果鹤虱(S.kaschgaricum-Lappula semiglabra)、新疆绢蒿-旱麦草(S.kaschgaricum-Eremopyrum triticeum)、勿忘草-草原苔草(Myosotis sylvatica-Carex liparocarpos)5个群落类型。去势典范对应分析(DCCA)表明经度、坡向、土壤有机质及pH值是决定天山北部拟南芥种群分布的主导因子。拟南芥分布与群落内其他物种有极强的依赖关系,与13个群落62个主要物种的种间联结性分析表明,共有119个正关联性种对,明显高于72个负关联性种对,与各群落优势种呈显著正关联。拟南芥种群分布数量在群落间差异较大,分布于降雨较少的天山中部浅山地带拟南芥种群数量均高于降雨较丰富的天山西部伊犁果子沟地区,是否发生适应性分化需要深入研究。

Arabidopsis thaliana is a model organism widely-used to study molecular and developmental biology, physiology and cell biology. The Tianshan Mountains is one of the main distribution regions of A. thaliana. To evaluate the distribution and the environmental stress ofA. thaliana in arid land, we character- ized A. thaliana communities in the northern Tianshan Mountains along with relevant environmental factors. Eight communities found in the middle Tianshan Mountains were herb types and their dominant species were similar, but another five communities distributed in the western Tianshans and Altai region were markedly different. The recorded 77 species were classified into 22 families and 64 genera, and species richness of the 13 communities was relatively low. Most species belonged to Cosmopolitan （areal-type 1）, North Temperate （areal-type 8）, Mediterranean, and West Asia to Central Asia （areal-type 12） areal-types, reflecting the arid and semi-arid geographical features of the area. Based on the Two-Way Indicator Species Analysis （TWIN- SPAN） method, the 13 communities were classified into five hierarchical levels： Seriphidium kaschgarieum-Salsola collina-Ceratocephalus testiculatus, S. kaschgaricum--S, collina, S. kaschgaricum-Lappula semiglabra, S. kaschgaricum-Eremopyrum triticeum, and Myosotis sylvatica-Cyperus microiria. Interspeci- fic association analysis showed that among 62 main species in the 13 communities, 119 species-pairs exhib- ited significant a positive association; more than the 72 species-pairs with a negative association. In particu- lar, A. thaliana showed a statistically significant, positive association with the dominant species in each community, indicating a strong positive dependence ofA. thaliana with other species. Detrended Canonical Correspondence Analysis （DCCA） showed that longitude, topography, soil organic matter and pH were the dominant factors affecting the distribution of A. thaliana populations in the northern Tianshan Mountains. Abundance and distribution of species differed among communities. Populations were more prevalent in the middle northern Tianshan Mountains with lower rainfall than in the western Tianshan Mountains. Further re- search is needed to explain whether there is the adaptive differentiation.