苦竹向茶园扩张后不同年龄立竹叶片的功能性状变化特征研究

Response of Leaf Functional Traits of Pleioblastus amarus at Differ-ent Ages During the Expansive Process into the Tea Plantations

为探究苦竹茶园扩张后叶片形态性状及养分变化规律,揭示其环境适应策略及觅养特征,以连续成片的苦竹-茶园扩张林分为研究对象,设置4种样地,分别为苦竹中心区(BF)、苦竹界面区(BA)、混交林界面区(MA)和混交林中心区(TB),分析1年生和2年生立竹的叶功能性状在扩展方向的变化特征。结果表明:沿苦竹向茶园扩张方向,1年生立竹叶形态性状呈逐渐增大趋势,在TB样地表现最高,但2年生立竹叶片形态性状随苦竹向茶园扩张呈“V”型变化,各指标在BA样地表现最低;1年生立竹叶比表面积及叶面积波动不对称性值在BA样地显著降低,但2年生立竹该指标在各样地间差异不显著。1年生立竹叶片CNP含量在BA样地显著高于其他样地,而2年生立竹叶片CN含量表现相反。不同年龄立竹叶片C∶N、C∶P、N∶P沿苦竹向茶园扩张方向均呈“V”型变化,在BA样地显著降低。随扩张进行,1年生立竹叶宽、叶面积、叶厚、叶干质量和比叶面积指标逐渐高于2年生立竹,在TB样地差异明显;各样地间1年生立竹CNP含量均高于2年生立竹,但C∶N、C∶P、N∶P表现相反,各指标在BA样地呈明显的年龄差异。总体而言,苦竹立竹叶功能性状间的权衡关系沿扩展方向发生了适应性调整,在资源竞争激烈的竹茶界面区域具有显著的年龄效应。

To explore the changes in leaf morphological characteristics and nutrient content of Pleioblastus amarus during its expansion into tea gardens,and reveal the adaptation strategies and nutrient acquisition charac-teristics,the study analyzed the response of leaf functional traits of 1-year-old and 2-year-old P.amarus during the expansion of P.amarus into tea garden.Four plots were established:P.amarus forest central area(BF),P.amarus forest interface area(BA),mixed forest interface area(MA),and mixed forest center area(TB).The findings re-vealed that along the direction of the expansion of P.amarus to the tea plantation,the leaf morphology of 1-year-old bamboo showed a trend of gradual increase,and the performance was the highest in the TB sample site,but the leaf morphology of 2-year-old bamboo showed a"V"-shaped change with the expansion of P.amarus to the tea plantation,and the performance of each index was the lowest in the BA sites;the values of the specific surface area of the leaf and the fluctuating asymmetricity of the leaf area of 1-year-old bamboo decreased significantly in the BA sites,but the differences of this index among the sample sites were not significant in 2-year-old bamboo.The CNP content of the 1-year-old bamboo leaf was significantly higher than that of other samples in the BA sites,while the CN content of the 2-year-old bamboo leaves showed the opposite behavior.The C∶N,C∶P,and N∶P of leaves of different ages of standing bamboo showed a"V"type change along the direction of the expan-sion of P.amarus to the tea plantation,and decreased significantly in the BA sites.The leaf width,leaf area,leaf thickness,leaf dry weight,and specific leaf area indexes of 1-year-old bamboo were gradually higher than those of 2-year-old bamboo with expansion,and the differences were obvious in the TB sites;the CNP content of 1-year-old bamboo was higher than that of 2-year-old bamboo among all the sampling plots,but the performance of C∶N,C∶P and N∶P was opposite,and all the indexes showed obvious age differences in the BA sites.Overall,the trade-off relationships among functional traits of P.amarus leaves were adaptively adjusted along the direc-tion of expansion,with significant age effects in the bamboo-tea interface region where resource competition is intense.