光环境对闽楠幼树生长及其表型可塑性的影响

The Effects of Light Environment on the Growth and the Phonotypic Plasticity of the Seedlings of Phoebe bournei

为提高林下闽楠更新层科学培育水平,在福建明溪进行不同光环境对闽楠幼树生长和表型可塑性影响试验。结果表明:光环境对闽楠幼林的生长具有显著影响,在促进闽楠幼林生长方面表现为林窗>林中旷地>林下。营建理想的光环境并适时增加光照强度,是闽楠人工林培育的关键技术措施。光环境对闽楠的冠长、冠幅、一级及二级侧枝密度和均长、叶生物量的分配比、侧枝生物量分配比和茎干生物量分配比都有极显著影响,表现出强烈的表型可塑性;光环境并未显著改变闽楠根系生物量分配比、冠根比和树冠圆满度。闽楠幼林在光环境适宜时,通过促进树冠生长,一级、二级侧枝萌发和生长,增加叶、枝生物量分配比,采取快速获取资源的策略;反之则抑制树冠生长,一级、二级侧枝萌发和生长,减少枝、叶生物量的分配比,采取保守消耗的策略。

In order to improve the scientific cultivation level of Phoebe bournei forest′s regeneration layer,a trials of different light regime on the growth and the phonotypic plasticity of Phoebe bournei seedlings were studied in Mingxi County of Fujian.The results showed that light environment had a significant impact on the growth of P.bournei seed-lings,and the sequence of promoting growth of the seedlings from high to low was gap,open and understory.Constructed a ideal light condition and timely to increase light intensity,was a key measure for P.bournei plantation.The light envi-ronment had a very significant impact on the crown length,crown width and 1 st and 2nd order lateral branch density and average length,leaf biomass allocation ratio,lateral branch biomass allocation ratio,stems biomass allocation ratio, which showed a strong phenotypic plasticity.However,light environment didn′t bring significantly change on root bio-mass allocation ratio,crown root ratio and CFR.of P.bournei seedlings.In the appropriate light condition,P.bournei seedlings were rapid resource acquisition,including promoted the growth of the canopy,1 st and 2nd order lateral branch germination and growth,increased leaf and branch biomass allocation ratio;Conversely,in adverse light condition,P. bournei seedlings inhibited the growth of canopy,1 st and 2nd order collateral germination and growth,reduced leaf and branch biomass allocation ratio,adopted a conservative consumed strategies.