单子叶植物核DNA含量地理纬度变异式样及其与气候因素关系

从"植物DNA C-值数据库"检索到2 852种单子叶植物的核DNA含量数据,沿经度方向均分为10条样带,每条样带沿纬度又均分成19个样块.从"世界气候数据网站"下载的19个生物气候因子数据,应用Arc GIS 9.3获得每个样块生物气候因子的平均值.根据"全球生物多样性信息网站"记录,计算每个样块的单子叶植物的平均核DNA含量.分析了最冷季度平均温度和最干季度雨量对单子叶植物核DNA含量的影响.应用分位数回归分析了核DNA含量不同的单子叶植物在全球范围的纬度梯度变化特点,以及气候适应性的差异.结果发现:单子叶植物的核DNA含量沿着纬度呈现非线性的规律变化;受气候因素影响,在中等温度和雨量环境下其核DNA含量最高,温度和水分趋向极端的环境下其核DNA含量较低,可以用"单峰"函数拟合;核DNA含量低的类群具有更广泛的全球分布.

Latitudinal variation patterns of nuclear DNA contents in monocotyledons on a global scale and their climatic adaptation significance

We conducted a research on the relationships of nuclear DNA with latitudes and climatic factors based on data of monocotyledons.Firstly,we obtained the data of nuclear DNA contents of 2 852 species of monocotyledons from the Plant DNA C-value database.And we selected ten global longitudinal transects,and evenly divided each transect into 19 blocks.We obtained geographical records of the 2 852 species from the Global Biodiversity Information Facility,together with nineteen bio-climatic factors within these blocks from the Worldclim (Global Climate Database).We calculated the average DNA 1C-values and genome sizes of each species in each block.Further,we analysed the influences of temperature of the coldest quarter and rainfall of driest quarter on nuclear DNA contents of monocotyledon species.And the results showed that the latitudinal variation patterns of monocotyledon nuclear DNA contents on a global scale were nonlinear on the transect 1 to 10 over the world,which is influenced by the temperature of the coldest quarter and rainfall of driest quarter,and these relationships can be described nonlinear.The results showed that:on the global scale plant nuclear DNA contents varied nonlinearly with latitude;the values were affected by climatic factors,which were highest in the regions with moderate temperature and rainfall,and decreased in the environment of extreme temperature and rainfall,the relationships between plant nuclear DNA values and climatic factors also being nonlinear,following "unimodal" functions;the groups with lower nuclear DNA values distributed widely on the global scale.