不同区域针叶年龄对红松叶性状及相关关系的影响

Effects of needle age on leaf traits and their correlations of Pinus koraiensis across different regions

叶龄是植株个体发育过程中性状变异的重要影响因素,不同叶龄下的性状变异可以体现植物针对环境变化做出的响应。该研究以东北地区4个不同区域阔叶红松(Pinus koraiensis)林中的成年红松为研究对象,测定了4个区域红松的叶寿命和不同针叶年龄叶片的比叶面积(SLA)、叶片干物质含量(LDMC)、针叶密度(ND)以及针叶体积(NV),探讨了红松叶形态性状间的相关性,并检验了纬度和针叶年龄对这些相关关系的影响。结果显示:(1)不同纬度下红松叶寿命存在显著差异,随纬度增加呈单峰模式。(2)针叶年龄在性状变异解释中占比最大(34.2%–80.1%),对4个叶形态性状均存在显著影响。SLA、LDMC和ND在当年生叶片中均表现了比所有龄级下更大的可塑性,仅NV在所有龄级下的可塑性大于当年生叶片。(3)4个性状间的二元相关性显著,且在不同纬度下多有体现,但性状间的回归斜率随纬度变化趋势存在差异。(4)不同针叶年龄性状间的相关关系依然显著但变异规律不同,如SLA与ND的回归斜率随针叶年龄增加而减小,ND与NV则相反。研究结果表明红松叶形态性状的变异和性状间的相关关系受纬度和针叶年龄的显著影响,性状协同应对不同纬度梯度导致的环境变化以及不同针叶年龄下叶片的资源利用策略存在差异。

Aims Leaf age is an important factor affecting trait variation during ontogenetic development of plants.The variation of traits across a gradient of leaf ages can reflect the response of plants to environmental changes.Our aim was to investigate the variation of needle morphological traits of Pinus koraiensis at different needle ages and the influence of latitude and needle age on the correlation of morphological traits.Methods In this study,adult Korean pine(Pinus koraiensis)of four mixed broadleaved-Korean pine forests in northeast China was selected as the research object.We measured the leaf lifespan,as well as specific leaf area(SLA),leaf dry matter content(LDMC),needle density(ND)and needle volume(NV)of needles at different ages.The correlation between morphological traits of pine leaves was discussed and the effects of latitude and needle age on these correlations were examined.Important findings(1)Leaf lifespan of P.koraiensis significantly varied with latitudes,and showed a unimodal pattern with increasing latitude.(2)Needle age accounted for the largest proportion(34.2%–80.1%)in trait variations,and had a significant influence on all the four leaf morphological traits.SLA,LDMC and ND of the current year leaves showed higher plasticity than other age classes,while NV showed high plasticity at all age classes.(3)Most of these trait-trait correlations were significant at different latitudes,while the patterns of slopes of the regression lines among traits did vary across the latitudinal gradient.(4)The correlations among traits within different needle ages classes were all significant,but showing different patterns across needle ages.For example,the regression slope of SLA and ND decreased with the increase of needle age,while the regression slope of ND and NV was opposite.The results showed that the variation and correlation of morphological traits were significantly influenced by latitude and needle age,the collaboration among these traits responded to the environmental changes at different latitudes,and the resource utilization strategies of needles were different in different ages.