Geographical variation in morphological traits may reflect evolutionary patterns of morphological adaptability along environmental gradients. Comprehensive information on longitudinal patterns of morphological trait variation is very meaningful to explore morphological diversity and evolutionary trends in widespread bermudagrass. To explore the spatial patterns of morphological traits, we investigated 10 morphological traits of bermudagrass and 10 soil nutrient indexes and collected local climate data for 13 different regions from 119°E to 105°E along the latitude 34°N. Considerable variations in morphological traits were observed at different longitudes, and the variations in most of the evaluated traits within populations were lower than those among populations. All of the 13 different longitudinal sites were divided into three groups based on morphological traits by cluster analysis. The major sources of diversity at the different longitudes were leaf length of the erect shoot, leaf width of the erect shoot, and the internode lengths of the erect shoot and stolon as determined by principal component analysis. Pearson correlation analysis also indicated that longitude was significantly and negatively correlated with these traits as well. Mean average rainfall was significantly correlated with leaf length of the erect shoot and the internode lengths of the erect shoot and stolon, while mean average temperature was only significantly correlated with internode length of the erect shoots. Available sulfur was significantly correlated with internode length of the erect shoot, plant height, and reproductive branch height, while the exchangeable Ca was significantly correlated with internode lengths of the erect shoot and stolon. Soil pH was significantly correlated with the internode length of the stolon. Longitude is an important factor that affects morphological trait variation in wild bermudagrass, and the leaves of the erect shoot and the internode length enlarged significantly with the collection sites moving from east to west. Different combinations and interactions of environmental factors (soil and climate) along a longitudinal gradient may have strong effects on one or more morphological traits of bermudagrass.

中文翻译：

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Cynodon dactylon (L.) Pers. 的形态变异及其与环境沿纵向梯度的关系

形态特征的地理变异可能反映了沿环境梯度形态适应性的进化模式。形态性状变异纵向模式的综合信息对于探索广泛分布的狗牙根的形态多样性和进化趋势非常有意义。为了探索形态性状的空间格局，我们调查了百慕大的 10 个形态性状和 10 个土壤养分指标，并收集了 119°E 至 105°E 沿 34°N 纬度的 13 个不同区域的局地气候数据。不同经度的形态性状变异较大，多数评价性状种群内变异低于种群间变异。通过聚类分析，基于形态特征将所有 13 个不同的纵向站点分为三组。主成分分析确定的不同经度多样性的主要来源是直立枝叶长、直立枝叶宽、直立枝和匍匐茎节间长度。Pearson 相关分析还表明，经度与这些性状也呈显着负相关。平均降雨量与直立枝叶长度、直立枝条和匍匐茎节间长度显着相关，而平均气温仅与直立枝条节间长度显着相关。有效硫与直立枝条节间长度、株高、和生殖枝高度，而可交换钙与直立枝条和匍匐茎的节间长度显着相关。土壤pH值与匍匐茎节间长度显着相关。经度是影响野生狗牙根形态性状变异的重要因素，随着采集地自东向西移动，直立枝条的叶片和节间长度显着增大。沿纵向梯度的环境因素（土壤和气候）的不同组合和相互作用可能对狗牙根的一种或多种形态特征产生强烈影响。经度是影响野生狗牙根形态性状变异的重要因素，随着采集地自东向西移动，直立枝条的叶片和节间长度显着增大。沿纵向梯度的环境因素（土壤和气候）的不同组合和相互作用可能对狗牙根的一种或多种形态特征产生强烈影响。经度是影响野生狗牙根形态性状变异的重要因素，随着采集地自东向西移动，直立枝条的叶片和节间长度显着增大。沿纵向梯度的环境因素（土壤和气候）的不同组合和相互作用可能对狗牙根的一种或多种形态特征产生强烈影响。