提前钩梢对雷竹地上构件生物量分配及其异速生长的影响

为摸清提前钩梢对雷竹地上构件生物量积累与分配及其异速生长模式的影响,为雷竹林合理钩梢提供参考,调查了5月(提前钩梢)、6月(常规时间钩梢)钩梢和未钩梢雷竹林新竹当年(1年生立竹)和第2年(2年生立竹)秆、枝、叶生物量,分析了立竹地上构件生物量积累与分配特征及其异速生长。结果表明:钩梢使雷竹1年生立竹秆、枝、叶生物量显著下降,秆生物量分配比例显著升高,枝、叶生物量分配比例显著下降,枝、叶-总生物量异速生长指数显著增大,秆-总生物量异速生长指数显著减小,且常规时间钩梢立竹叶生物量及其分配比例和出叶强度均显著高于提前钩梢立竹。钩梢也导致雷竹2年生立竹秆、枝、叶生物量明显下降,但秆、枝、叶-总生物量异速生长指数均显著增大,常规时间钩梢立竹叶生物量仅略低于未钩梢立竹,且叶生物量分配比例及出叶强度均显著高于未钩梢和提前钩梢立竹。研究表明提前钩梢对雷竹叶生物量及其分配比例、出叶强度及异速生长均有明显的负面影响,不利于雷竹林光合能力的发挥,因此,雷竹林不宜提前钩梢。

Effect of early obtruncation on aboveground biomass accumulation and allocation, and the allometric growth of Phyllostachys violascens

The responses of aboveground module biomass accumulation and Phyllostachys violascens allometric growth to obtruncation were studied to recommend scientific obtruncation practice. The stem, branch and leaf biomasses of one-year old (1 a) and two-year old (2 a) bamboos either obtruncated or not obtruncated were determined. The allometric growth in biomass was also analyzed. The results showed that obtruncation considerably reduced the stem, branch and leaf biomass of 1 a bamboos. The allocation to stem biomass markedly increased, whereas allocation to branch and leaf biomass decreased considerably. The slopes for the branch and leaf biomass-total biomass of 1 a bamboos significantly increased, whereas the slope for stem biomass decreased. Furthermore, the leaf biomass and its allocation, and the leafing intensity of the bamboos obtruncated at the normal time were all clearly higher than those of the early obtruncated bamboos. The stem, branch and leaf biomass of 2 a bamboos decreased overall after obtruncation, whereas the slopes for branch, stem and leaf biomass-total biomass considerably increased. Furthermore, the leaf biomass of bamboo obtruncated at the normal time was slightly lower than the non-obtruncated bamboos. The leaf biomass allocation and leafing intensity of bamboos obtruncated at the normal time were also higher than those of non-obtruncated and early obtruncated bamboos. All the results indicated that early obtruncation had negative impact on the accumulation of leaf biomass and its allocation, leafing intensity, and biomass allometry. Early obtruncation may also limit the photosynthetic capacity of bamboos. Therefore, early obtruncation is not recommended as a bamboo cultivation practice.