地上竞争和光照对打碗花生长策略的影响

裴丽梅 屠渺 杨佩

摘要：以打碗花（Calystegia hederacea）为材料，使幼苗分别在地上竞争（有地上竞争和无地上竞争）和光照条件（强光照和弱光照）下生长，监测地上茎长、平均茎节长度随植株生长的变化，并在收获时测量各部分生物量以及产生分枝数目。结果表明，有地上竞争相比无地上竞争，地上茎相对生长速率更快，且茎叶生物量分配提高、根系生物量分配下降。弱光照处理相比强光照处理，地上茎相对生长速率更快，分枝数目更少，且茎叶生物量分配提高、根系生物量分配下降。以地上茎长为参考指标计算竞争强度，弱光下地上竞争的竞争强度是强光下的2倍;从生物量分配上看，ANOVA分析显示光照条件和竞争效应并无显著交互作用。此外，地上茎长度随时间而增加的同时，平均茎节长度却随时间轻微下降。

关键词：地上竞争;光照;限制性资源;地上茎长;生物量分配;打碗花（Calystegia hederacea）

中图分类号：Q948.12         文献标识码：A

文章编号：0439-8114（2019）10-0085-03

DOI：10.14088/j.cnki.issn0439-8114.2019.10.019           开放科学（资源服务）标识码（OSID）：

Abstract： Taking Calystegia hederacea as material， the seedlings were grown under overground competition （with overground competition and without overground competition） and under light conditions （strong light and weak light）， and the changes of overground stem length and average stem node length with plant growth were monitored. Biomass of each part and number of branches were measured at harvest. The results showed that compared with no above-ground competition， the relative growth rate of above-ground stems was faster， and the biomass distribution of stems and leaves was increased， while that of roots was decreased. The weak light treatment compared with the strong light treatment， the growth rate of the stems was faster， the number of branches was less， the biomass distribution of the stems and leaves was higher， and the biomass distribution of the roots was lower. The competition intensity was calculated by using the length of the overground stem as the reference index. In terms of biomass allocation， ANOVA analysis showed that there was no significant interaction between light condition and competitive effect. In addition， while the stem length increased with time， the average stem node length decreased slightly with time.

Key words： above-ground competition; light availability; limiting resource; stem length; biomass allocation; Calystegia hederacea

植物個体面对地上竞争者为了避免被遮阴，会增加株高而减少侧生生长，调整生物量分配策略[1]，以增加对光资源的获取，这种由于光竞争所引起的可塑性反应被称为遮阴回避效应（Shade avoidance）[2]。最优分配理论（Optimal partitioning theory）认为，植物会将资源优先分配给可以提高限制性资源获取的器官[3]，比如土壤资源受限时植株会提高根系生物量分配[4，5];且大量事实表明，植物根系会综合土壤中的根系竞争者和土壤肥力，作出综合性的反馈[6]。地上茎叶与光资源之间可能也存在竞争和资源的交互作用。……