顶坛花椒叶功能性状对经营措施的响应

Leaf functional traits of Zanthoxylum planispinum var.dintanensis and their response to management measures

为探明不同经营措施对顶坛花椒叶片形态性状、叶片养分含量和光合生理特征的影响,筛选喀斯特石漠化地区顶坛花椒种植最优的经营措施,以贵州省关岭县不同经营措施种植的顶坛花椒(Zanthoxylum planispinum var.dintanensis)人工林为研究对象,测定其叶片形态性状、生态化学计量和光合生理参数,研究其叶片功能性状对经营措施的响应。结果表明:与自然生长的顶坛花椒林相比,矮化密植和喷灌处理后,顶坛花椒的叶鲜重、叶饱和鲜重、叶面积、叶干重分别增加26%~31%、19%~29%、18%~23%、19%~33%;而叶组织密度、叶干物质含量在矮化密植+喷灌中均降低了7%,在矮化密植中分别升高4%和11%;矮化密植的比叶面积较自然生长减小12%,矮化密植+喷灌与自然生长无显著性差异,表明矮化密植与喷灌一定程度引起了顶坛花椒叶片形态性状的变化。矮化密植与喷灌显著降低了顶坛花椒叶片有机碳含量,但是对全氮和全磷含量的影响不明显。经营措施促使顶坛花椒净光合速率提高了77%~136%,矮化密植+喷灌对花椒光合速率的提升最明显。顶坛花椒叶片功能性状之间存在显著或极显著相关关系,其中形态性状与光合生理性状的相关性最强。经营措施能够引起顶坛花椒生长和防御相关叶片功能性状的响应,花椒通过权衡策略进行了资源的优化配置。较自然生长而言,矮化密植+喷灌处理的顶坛花椒在叶经济谱中更靠近“快速投资-收益”型的一端,表明喀斯特地区顶坛花椒种植应适当修枝整形与喷灌,提其高生长速率。

Leaf functional traits are important indicators of environmental variability,and the study of their response patterns to management measures can help better understand the adaptation of plants to disturbance mechanisms and contribute to the management of plantation forests.In this study,leaf morphological traits,ecological stoichiometric characteristics,and photosynthetic physiological characteristics of Zanthoxylum planispinum var.dintanensis plantations in Guanling County,Guizhou Province,were evaluated to study their responses to different management measures.The results showed that:compared with natural growth,dwarf dense planting and sprinkling irrigation increased leaf fresh mass(LMF),leaf saturation fresh mass(LMSF),leaf area(LA),and leaf dry mass(LMD)by 26%-31%,19%-29%,18%-23%,and 19%-33%,respectively.However,both leaf tissue density(LTD)and leaf dry matter content(LDMC)decreased by 7%in dwarf dense planting+sprinkling irrigation and increased by 4%and 11%in dwarf dense planting.The specific leaf area(SLA)of dwarf dense planting decreased by 12%compared to that of natural growth.However,no significant difference was observed between SLA dwarf dense planting+sprinkling irrigation and natural growth indicating that dwarf dense planting and sprinkling irrigation caused minor changes in the morphological traits of Z.planispinum var.dintanensis leaves.Dwarf dense planting and sprinkling irrigation significantly reduced the leaf organic carbon(OC)content of Z.planispinum var.dintanensis;however,the effects on total nitrogen(TN)and total phosphorus(TP)content were not significant.Management measures contributed to a 77%-136%increase in P n and dwarf dense planting+sprinkling irrigation had the most significant increase in the photosynthetic rate of Z.planispinum var.dintanensis.Significant or highly significant correlations were observed between the functional traits of Z.planispinum var.dintanensis leaves,with morphological traits and photosynthetic physiological characteristics having the strongest correlations.Management measures can induce responses in leaf functional traits related to growth and defense in Z.planispinum var.dintanensis,and they were optimally allocated to resources through a trade-off strategy.With dwarf dense planting and sprinkling irrigation measures,Z.planispinum var.dintanensis is closer to the"quick investment-return"side of the leaf economic spectrum than natural growth,implying that its plantings in karst areas should be pruned and appropriately sprinkled to improve the growth rate.