红松不同生活史阶段的枝叶权衡

Trade-Off between Twig and Leaf of Pinus koraiensis at Different Life History Stages

【目的】枝叶大小、出叶强度之间的关系反映了植物空间资源利用能力,研究不同生活史阶段及不同枝叶年龄的枝叶性状变异及其权衡对预测种内变异和植物在不同环境条件下的生存策略具有重要意义。【方法】以黑龙江凉水国家级自然保护区阔叶红松林的建群种红松为研究对象,选取4个不同生活史阶段(幼苗、幼树、成年树、老龄树)的样树,测定其不同枝叶年龄的枝横截面积、单叶面积、总叶面积和出叶强度。采用单因素方差分析法检验枝性状与叶性状在不同生活史阶段、不同枝叶年龄是否存在显著差异。以标准化主轴估计(SMA)检验不同生活史阶段对当年生枝横截面积与单叶面积、总叶面积、出叶强度,以及单叶面积与出叶强度间相关关系是否存在显著影响,以及枝叶年龄对枝横截面积与总叶面积、出叶强度的相关关系是否存在显著影响。【结果】1)随生活史阶段上升,红松枝横截面积、叶面积呈上升趋势,出叶强度呈下降趋势,且枝、叶性状在4个生活史阶段的不同枝叶年龄间存在显著差异,枝叶年龄可解释最多的枝叶性状变异,生活史阶段可分别解释枝横截面积、总叶面积和单叶面积变异的17%、7%和3%;2)红松不同生活史阶段当年生枝-叶性状均呈异速生长;3)幼树、成年树和老龄树阶段的1年生枝横截面积与总叶面积均呈正相关关系;老龄树阶段当年生、1年生和2年生枝横截面积与出叶强度均呈负相关关系。【结论】红松不同生活史阶段植物资源利用策略存在差异,仅幼苗阶段当年生枝-叶性状均存在相关关系;红松不同枝叶年龄枝-叶性状均呈异速生长。

【Objective】The relationship between leaf size,twig size and leafing intensity reflects the ability of plant to use spatial resources.Our objective was to reveal the variation and trade-off of leaf and twig traits at different ages of leaf and twig at different life history stages for predicting intraspecific variations and plant survival strategies under different resource conditions.【Method】In Liangshui National Nature Reserve of Heilongjiang Province,Pinus koraiensis is the main dominant species of mixed broadleaved-P.koraiensis forest,sample trees of the species at four different life history stages(seedlings,saplings,adult trees and old trees)were selected to measure their cross-sectional area of twig,individual leaf area,total leaf area and volume-based leafing intensity at different ages of leaf and twig.One-way ANOVA was conducted to test significance of the variations in leaf and twig traits among different life history stages and different leaf and twig ages.The method of standardized major axis(SMA)was used to examine the influence of current-year twigs and leaves at different life history stages on the relationships between twig cross-sectional area and individual leaf area,total leaf area,volume-based leafing intensity and between individual leaf area and volume-based leafing intensity,and the influence of leaf and twig ages on the relationships between twig cross-sectional area and total leaf area,volume-based leafing intensity.【Result】The twig cross-sectional area and leaf area increased with the gradient of life history stages,while the leafing intensity decreased.There were significant differences in twig and leaf traits among leaf and twig ages.Leaf and twig ages accounted for the most of the variations in leaf and twig traits.Life history stages accounted for 17%,7%and 3%of the total variation of twig cross-sectional area,total leaf area and individual leaf area.The correlation between current year twig and leaf traits at different life history stages showed heterotrophic growth.At sapling,adult tree and old tree stage,there was a significant positive correlation between the one-year-old twig cross-sectional area and the total leaf area;while there was a negative correlation between the current-year,one-year-old and two-year-old twig cross-sectional area and leafing intensity at old tree stage.【Conclusion】At different life history stages of P.koraiensis,the trade-off strategies of the twigs and leaves were different.There was a correlation between the current-year twig and leaf traits at the seedling stage.The twig and leaf traits showed allometric growth at different ages of twigs and leaves.