中国竹类植物基本形态学功能性状的比较

竹类植物作为一种克隆植物, 无次生生长过程, 具有独特的生长和繁殖特性。但有关不同类群竹类植物功能性状的变异规律所知甚少。本文以在中国分布的34属534种竹类植物为研究对象, 从Flora of China中收集和整理其秆高、直径、节间长、竹壁厚、叶长、叶宽等基本形态学功能性状, 根据竹类植物生物学特性, 按地下茎划分为丛生、散生和混生3个类群, 按出笋季节划分为春、夏、秋、冬4个类群, 按分布范围划分为中国特有(371个中国特有种)和非特有2个类群, 再采用方差分析和多重比较探讨不同类群竹类植物在基本形态学性状上的分异格局, 采用主成分分析揭示各个功能性状之间的内在关联, 剖析不同类群竹类植物功能性状的变异。结果表明: 丛生竹、散生竹和混生竹之间功能性状差异显著, 丛生竹具有最大的秆高、直径、节间长、竹壁厚, 最小的叶长和叶宽, 散生竹次之, 而混生竹则具有最小的秆性状和最大的叶性状。中国特有种在秆高、直径、竹壁厚、叶长方面显著小于非特有种。竹类植物秆高、直径、节间长、竹壁厚之间均呈显著正相关, 叶长和叶宽之间存在显著正相关。竹类植物在垂直方向上的大小性状(主要包括直径、秆高和竹壁厚)在第一主轴具有较大的贡献率, 而在水平方向上的叶片功能性状(叶长和叶宽)在第二主轴上贡献率最大。由此可见, 竹类植物在水平方向和垂直方向上对光资源的捕获差异可能是驱动竹类植物系统演化、特有性分布和出笋季节差异的关键因素。

Variation in basic morphological and functional traits of Chinese bamboo

Bamboo is a clonal plant that lacks a secondary growth process and has unique growth and reproduction characteristics. However, little is known about the variation in functional traits of bamboo among different functional group. In this study, all 534 known bamboo species (34 genera) in China were used as research subjects. Data of biological characteristics of these bamboo species was collected and organized from Flora of China, including various types of functional group and different functional traits. Types of functional group included rhizome type (sympodial, monopodial or mixed), shooting season (spring, summer, autumn or winter) and endemism (371 species endemic to China). Functional traits included height, diameter, internode length, wall thickness, leaf length and leaf width. Analysis of variance and multiple contrasts were performed to explore the variation in the basic morphological traits of bamboo among the different functional groups. Principal component analysis (PCA) was employed to explore the intrinsic correlations among functional traits and analyze functional trait variation in different functional groups of bamboo plants. The results show that: (1) Sympodial, monopodial and mixed bamboos differed significantly in their functional traits. Sympodial bamboo plants had the largest height, diameter, internode length and wall thickness, and the smallest leaf length and leaf width, followed by mixed bamboo plants. Meanwhile, monopodial bamboo plants had the smallest pole traits and the largest leaf traits. Species endemic to China had significantly smaller values for height, diameter, wall thickness and leaf length than non-endemic species. (2) There were significant positive correlations among bamboo plant height, diameter, internode length and wall thickness. Also, there was a positive correlation between leaf length and leaf width. (3) The “size traits” (diameter, culm height and wall thickness of bamboo) in vertical direction contributed more to the first principal component axis, while the “leaf traits” (leaf length and leaf width) in horizontal direction contributed more to the second principal component axis. These results show that for bamboo plants, the variation in capturing light resources in both horizontal and vertical directions may be the key factors driving the systematic evolution, the endemic distribution and the seasonal difference in bamboo shooting.