模拟增温和功能群去除对岷江冷杉幼苗存活和生长的影响

Effects of simulated warming and functional group removal on survival and growth of Abies faxoniana seedlings

通过模拟增温和功能群去除试验,研究不同功能群的草本植物在岷江冷杉幼苗更新定植过程的作用,分析其在温度升高条件下生理指标的变化.结果表明:增温提高了岷江冷杉幼苗的存活率和植物体内非结构性碳水化合物含量,但抑制了幼苗的生长和根冠比.岷江冷杉幼苗的非结构性碳水化合物含量,尤其是可溶性糖含量与存活率呈显著正相关.不增温处理中,草本植物降低了幼苗的存活率,促进幼苗的株高生长和地上生物量积累,禾本科植物和杂类草抑制了幼苗根系生长和地下生物量的积累;增温处理中,杂类草的存在提高了幼苗的存活率,莎草科则显著抑制了幼苗根系生长和地下生物量的积累,禾本科植物和杂类草抑制了幼苗的高生长和地上生物量积累.模拟增温提高了林线树种岷江冷杉幼苗的存活率,但使其面临来自草本植物更剧烈的竞争,抑制其生长.

Warming and herbaceous functional group removal experiment was conducted in subal- pine meadow to examine the effects of herbaceous species on Abies faxoniana seedlings by analyzing its physiological responses. The survival rate and non-structural carbohydrate content were significantly increased, but the growth and root/shoot of A. faxoniana were decreased. Seedling survival was significantly positively correlated with non-structural carbohydrate content, especially with soluble sugar. Under the treatment without warming, herbaceous species inhibited the survival of A. faxoniana, increased height growth and aboveground biomass. Grasses and forbs decreased the root length and belowground biomass of A. faxoniana. In the warming treatment, forbs increased the survival of A. faxoniana, sedges decreased root length and belowground biomass of A. faxoniana, and grasses and forbs decreased height growth and aboveground biomass of A. faxoniana. Simulated warming increased the survival of A. faxoniana seedlings, but also made it face stronger competition from herbaceous and thus inhibited its growth.