贵州雷公山秃杉林不同林冠环境下箭竹分株种群结构特征

Ramet Population Structures of Sinarundinaria basihursuta on Different Canopy Conditions of Taiwania flousiana Forest in Leigong Mountain of Guizhou Province

通过对贵州雷公山秃杉林的4种林冠环境,即林下(FU)、中林窗(MG)、大林窗(LG)和林缘旷地(FEW)内的箭竹的分株种群结构(包括株高、基径、生物量、叶和分株数等)和年龄结构进行较系统对比研究。结果显示:(1)从林下→中林窗→大林窗,箭竹分株种群的株高(h)、基径(bd)与生物量显著增加。(2)在4种林窗环境中,箭竹各构件的生物量的百分比发生相应变化,枝和叶片生物量的百分比沿林下→中林窗→大林窗→林缘旷地的顺序显著减小,在林缘旷地,地下茎、粗根(d>0.5mm)和细根(d≤0.5mm)生物量的百分比显著高于其他3种林冠环境。(3)箭竹分株单位叶面积叶重沿林下→中林窗→大林窗→林缘旷地的顺序显著增大,单叶生物量与叶面积以中林窗最大,林缘旷地次之,二者与大林窗或林下差异显著;大林窗的单株叶片数显著高于其余3种林冠环境。(4)在4种林冠环境中,箭竹分株种群死亡率以林下最低,但各种群平均年龄间无显著差异。研究表明,箭竹分株种群对林冠环境变化的响应主要体现在形态与生物量的分配上,而非种群的年龄。

To study the impacts of different forest canopy conditions of Taiwania flousiana forest on Sinarundinaria basihursuta population,and reveal whether they affect the ramet structures and to estimate the effect sizes,we systematically conducted comparative survey about ramet population structures （including height,basal diameter, biomass allocation,leaf area and number of ramets） and age structure of S. basihursuta in ： forest understory （FU, S = 50.7 mz ）, moderate gap （MG, S = 160.4 m2 ）, large gap （LG, S ~ 406. 7 m2） and forest edge wildness（FEW,S= 1 086.3 m2） of T. flousiana forest in Leigong Mountain Nature Reserve of Guizhou Province,Southwestern China. The main results showed that： （1）The height（h）,basal diameter （bd） and biomass of S. basihursuta ramet population significantly increased in the sequence of FU --~MG--~LG. （2）The modular biomass percentage of S. basihursuta ramets varied with different canopy conditions. Branch and leaf biomass percentage decreased in the order of FU--＊MG---~LG-~FEW. The bio- mass percentage of rhizome and roots in the FEW were both significantly higher than those in the other three canopy environments. （3）The ramet specific leaf weight significantly increased in the sequence of FU --＊MG--＊LG--＊FEW. In the MG,the individnal leaf hir^ma~ wn~ th~ ho^vio~＊ nncl tho ~ncli,r^rt,,~l loaf tholargest,followed by those in the FEW, both were respectively different from those in the FU or LG; Leaf number per ramet in the LG was the biggest and was significantly different from the other three canopy conditions; （4）The ramet population mortality was the lowest in the FU, while there was no significant difference in the average population age. All the results indicated that it was not ramet age, but the morphological changes and biomass distribution that exhibited the response of the ramet population of S. basi- hursuta to changed canopy conditions.