摘要: |
研究不同径级树木的水力性状变异格局对了解其体内的水分传输机制具有重要的生理学意义。本研究以元江干热河谷生态系统中优势乔木树种厚皮树 (Lannea coromandelica)为研究对象,测定了56棵不同胸径(0 < DBH ≤ 9 cm)厚皮树的整枝(叶片和枝条)导水率、叶片导水率和枝条导水率分布格局及其形态学特征,进而探讨这些性状在三个胸径径级(0 < DBH ≤ 3, 3 < DBH ≤ 6 和6 < DBH ≤ 9 cm)间的变异格局。结果表明:(1)三个不同径级的厚皮树的枝条导水率均显著大于叶片导水率,表明其枝条和叶片之间存在水力分割现象,且水力分割程度相似;(2)在三个不同径级之间,平均叶柄长度、树皮密度、边材密度、胡伯尔值和比叶重等形态学性状存在显著差异,但是整枝、叶片和枝条导水率无显著差异;(3)在三个径级中,整枝导水率与叶片导水率和枝条导水率均存在显著的正相关关系。枝条导水率与树皮密度显著负相关,与边材密度显著正相关。叶片导水率与胡伯尔值显著负相关。综上,尽管一些形态学性状在不同径级之间有显著差异性,但在不同生长阶段,厚皮树叶片和枝条之间存在着类似的水力分布格局。 |
关键词: 干热河谷,水力性状,形态性状,水分传输 |
DOI: |
分类号:Q945 |
基金项目:国家自然科学基金项目(32171507,31901285,31870385);中国科学院西部之光项目(2020000021);云南省基础研究专项青年项目(202001AU070128)。 |
|
Patterns of variation in hydraulic traits of Lannea coromandelica with different diameter at breast height in Yuanjiang, Yunnan Province |
Yang Da1, Wang Qin1, Ke Yan1, Yang Shijian2,3, Zhang Jiaolin1
|
|
Abstract: |
Investigating the variation patterns of hydraulic traits of trees with different diameter at breast height (DBH) grades has important physiological significance for understanding the water transport mechanism in plants. We focused a dominant tree species (Lannea coromandelica) in the dry and hot ecosystem of the Yuanjiang River, and measured the distribution patterns of hydraulic traits including shoot- (leaves and stems), leaf-, and stem hydraulic conductance, and morphological properties (diameter at breast height, leaf area/petiole length, leaf area/mass of petiole, mass of leaf/mass of petiole, average petiole length, bark density, wood density, Huber value and leaf mass per area) for 56 L. coromandelica individuals with different DBHs (0 < DBH ≤ 9 cm), and then discussed the variation patterns of these traits among these three DBH levels (0 < DBH ≤ 3, 3 < DBH ≤ 6 and 6 < DBH ≤ 9 cm). The results showed that: (1) the stem hydraulic conductance was significantly greater than leaf hydraulic conductance in three DBH grades, indicating that there was a hydraulic segmentation between the stem and leaves, whereas the degree of hydraulic segmentation had a similar pattern. (2) Among the three different diameter grades, there were significant differences in morphological traits such as average petiole length, bark density, wood density, Huber value and leaf mass per area, but there were no significant differences in the hydraulic conductance of the shoot, stem, and leaf. (3) Among the three diameter grades, the shoot hydraulic conductance was positively correlated with leaf and stem hydraulic conductance, indicating there was a coordination between leaf and stem hydraulic conductance. The shoot hydraulic conductance was negatively correlated with bark density and wood density, and leaf hydraulic conductance was significantly negatively correlated with the Huber value, indicating these leaf and stem morphological properties may impact shoot and leaf hydraulic conductance. Overall, this study suggests that there are similar hydraulic distribution patterns between leaves and the stem of L. coromandelica at different growth stages, although some morphological traits differ significantly among different diameter grades. These results improve our understanding for the intra-specific variation in leaf and stem hydraulic traits of valley savanna plants. |
Key words: hot and dry valley, hydraulic traits, morphological traits, water transport |