刈割频度和刈割时间对冷地早熟禾生长的影响

The impact of mowing frequencies and time on the growth of Poa crymophila

在野外条件下,采用析因设计,对刈割频度和刈割时间变化下冷地早熟禾(Poa crymophila)生长情况进行研究,探讨冷地早熟禾对环境干扰的适应对策。刈割频度分为刈割1次、刈割2次和刈割3次,刈割时间分为早期刈割和晚期刈割。结果表明,所有刈割处理下,冷地早熟禾均发生了超补偿反应,超补偿的发生与刈割频度和刈割时间无关。地上生物量与分蘖数呈显著的正相关,冷地早熟禾是通过长出更多的分蘖来抵抗环境干扰的,新生分蘖产生所需的资源主要是由根部供应。冷地早熟禾对于不同时间的刈割处理,在生活史对策方面进行了权衡。早期刈割处理中,植物采取尽快产生种子,保证能够用种子繁殖后代的策略;晚期刈割处理中,植物采取了减少种子产生,保证植株个体来年存活和返青的策略。资源在植物体内进行重新分配和权衡是冷地早熟禾应对外界环境干扰的主要的适应对策。

With a purpose for strategies of Poa crymophila to adapt to environmental interference,we studiedthe growth of P.crymophila subject to varying moving frequencies and time using factorial design and in field conditions.Mowing frequencies are divided into one time,two times,and three times;and the mowing time is divided into early mowing and late mowing.The results showed that overcompensation effects occurred with all the P.crymophilain all cases,and the occurrence of overcompensation was irrelevant to moving frequencies and time.Above-ground biomass and tiller number had a significant positive correlation,P.crymophilaresisted environmental interference by growing more tillers,and the resources required to produce tillers were mainly supplied by the roots.The mowing treatments of P.crymophilaat different time were evaluated in respect of life history strategy.In case of early moving treatment,plants produced seeds as soon as possible to ensure their capability of production of the seeds;in case of late mowing,plants reduced the production of seeds to ensure the survival of individual plants in the coming year and taking root.Redistribution and balancing of resources in plants was the major strategy of P.crymophilato respond to interference of external environment.