文献类型：期刊文献

中文题名：西南桦幼林冠层光合特征及其对造林密度的响应

英文题名：Photosynthetic characteristics in crown and its response to planting density of young Betula alnoides

作者：骆丹[1] 王春胜[1] 曾杰[1]

第一作者：骆丹

机构：[1]中国林业科学研究院热带林业研究所,广东广州510520

年份：2020

卷号：40

期号：4

起止页码：44-49

中文期刊名：中南林业科技大学学报

外文期刊名：Journal of Central South University of Forestry & Technology

收录：CSTPCD;;北大核心:【北大核心2017】；CSCD:【CSCD2019_2020】；

基金：广东省自然科学基金博士科研启动项目(2016A030310008);国家自然科学基金青年科学基础项目(31600501);国家重点研发计划项目(2016YFD0600604)。

语种：中文

中文关键词：西南桦;冠层;光合特征;造林密度

外文关键词：Betula alnoides;crown layer;photosynthetic characteristics;planting density

分类号：S753.51

摘要：【目的】为探究不同造林密度条件下西南桦Betula alnoides幼林冠层光合生理特征,进而为西南桦造林密度和修枝强度的合理配置提供理论依据。【方法】以6年生西南桦无性系密度试验林为对象,每个密度处理选取3株优势木,将每个单株6 m以下树冠按每段1 m划分为2~4个冠层(2~3m、3~4m、4~5m、5~6m),每个冠层选择一位于阳面中间位置的平均枝,测定位于枝近顶端的4片发育完满叶光响应曲线。【结果】1)西南桦幼林冠层间最大光合速率、光饱和点和光补偿点均差异显著(P<0.05),这些指标均随冠层的升高而显著增大,表明上部冠层光合能力较强,且对强光的利用能力高。2)西南桦幼林冠层暗呼吸速率随冠层上升虽有降低趋势,但不同冠层间未达显著差异水平(P≥0.05)。3)相同冠层条件下,造林密度显著影响西南桦幼林冠层的表观量子效率、最大光合速率及光饱和点,三者均随造林密度增加呈显著下降趋势,特别是冠层3~4 m和5~6 m规律更明显。但是造林密度对于西南桦幼光补偿点和树暗呼吸速率无显著的影响。【结论】总体而言,西南桦幼林上部树冠表现出更大的光合潜力,冠层对于西南桦幼林光合能力的影响要高于造林密度,且两者存在明显的交互作用。研究将为珍贵树种通过合理修枝调控林木生长提供理论支撑。
【Objective】In order to explore the influence of planting density on photosynthetic characteristics in crown of young Betula alnoides plantation,and provide further theoretical guidance for proper arrangements in planting density and pruning intensity,light response curves were measured in a planting density experiment of B.alnoides when six years old.【Method】Three dominant trees were selected from each density treatments,and 2-4 crown layers were divided for each crown below 6 meters with 1 meter per crown layer.A mean branch was selected for measurement in the middle part and sunny side of each crown layer.Light response curves were measured for 4 fully developed leaves near the top of each mean branch.【Result】1)The results showed that the maximum photosynthetic rate,light saturation point and light compensation point of young B.alnoides were significantly affected by crown layer,and they increased significantly with the increment of crown layer.This showed that the upper crown layers had higher photosynthetic capacity and could use high light more efficiently than lower crown layers.2)Though there was a decreasing trend for dark respiration rate with increasing crown layers,no significant difference was found(P≥0.05).3)Within the same crown layer,planting density had significant effects on apparent quantum yield,maximum photosynthetic rate and light saturation point of young B.alnoides.There were decreasing trends for these indexes with the increment of planting density,especially for crown layer 3-4 m and 5-6 m.However,there was no significant difference in dark respiration and light compensation point among planting density treatments.【Conclusion】As a whole,the upper crown layers of young B.alnoides had higher photosynthetic potential,crown layer had a stronger effect on photosynthetic capacity than planting density,and significant interactions were found between both factors.The study could provide theoretical supports on growth regulation by artificial pruning for valuable tree species.