五种松属树种针叶长度与叶水力功能、结构的关系

Correlations between Needle Length and Leaf Hydraulics,Structure in Five Pinus Species

[目的]探究松属树种针叶长度与叶水力功能、结构的关系。[方法]以5种松属树种(萌芽松、湿地松、长叶松、火炬松、矮松)为研究对象,测定各树种针叶的水力导度、阻力分配和解剖结构,分析这些指标的种间变异及其与针叶长度的关系。[结果]5种松属树种针叶长度的变化范围为7.5~34.6 cm,随针叶长度的增加,叶水力导度(K_(leaf))、木质部导度(K_(xylem))、木质部外导度(K_(outside-xylem))、纹孔导度(K_(pits))均增加,但管胞腔导度(K_(lumen))降低。K_(leaf)的增加与K_(xylem)、K_(outside-xylem)的共同增加有关,而K_(xylem)的增加主要由K_(pits)的增加导致。在导水阻力方面,针叶在木质部中的导水阻力分配比例明显高于木质部外,且与针叶长度的变化无关。管胞腔中导水阻力的分配比例随针叶长度的增加而显著增加,这可能原因是水分的轴向运输距离增加。[结论]松属树种的针叶长度与叶水力功能、解剖结构具有密切的联系。该研究结果揭示了松属树种叶大小与叶水力功能、结构的关系,对深入认识叶功能性状之间的关系具有重要意义。

[Objective]The purpose of this study was to explore the relationship between pine needle length and leaf hydraulic function,structure in Pinus species.[Method]In this study,the hydraulic conductance,resistance distribution and anatomical structure of needles in five Pinus species(Pinus echinata Mill.,P.elliottii Engelm.,P.palustris Mill.,P.taeda L.,P.virginiana Mill.)were measured,and the interspecific variation of these indexes and their relationship with needle length were analyzed.[Result]The needle length have a range of 7.5~34.6 cm in five Pinus species,with the increase of needle length,the leaf hydraulic conductance(K_(leaf)),xylem conductance(K_(xylem)),outside-xylem conductance(K_(outside-xylem))and pit conductance(K_(pits))increased,but the tracheid lumen conductance(K_(lumen))decreased.The increase in K_(leaf) was associated with the co-increase in K_(xylem) and K outside-xylem,and the increase in K_(xylem) was mainly caused by the increase in K_(pits).In terms of hydraulic resistance,the distribution proportion of hydraulic resistance in the needle xylem was significantly higher than that outside the xylem,and it was not related to the change of pine needle length.The distribution proportion of hydraulic resistance in the tracheid lumen increased significantly with the increase of needle length,which might be due to the increase of the axial water transport distance.[Conclusion]The needle length of Pinus species is closely related to the leaf hydraulic function and anatomical structure.The results of this study reveal the relationships between leaf size and leaf hydraulic function and structure,which is of great significance for understanding the relationships among leaf functional traits.