刈割后两种不同体型植物的补偿式样对比研究

COMPENSATORY GROWTH RESPONSES OF TWO PLANTS WITH DIFFERENT GROWTH FORMS AFTER CLIPPING

对比了两种不同体型植物燕麦(Avenasativa)和油菜(Brassicacampestris)在不同施肥水平下的刈割反应特点。结果表明:对于燕麦而言,在不施肥条件下,3个时期的轻度刈割处理与对照相比,其生物量、总生物量、果重、果数等都有增加,但只有某些指标出现超补偿;在施肥条件下,各种刈割处理后均没有发生超补偿。并且无论施肥与否,分蘖期与拔节期的补偿指数均高于抽穗期的补偿指数。可以认为,不施肥条件下营养期轻度刈割处理较有利于燕麦的补偿生长。对于油菜而言,花蕾期轻度刈割处理后植物补偿指数最大,且施肥条件下的补偿指数高于不施肥条件下的补偿指数。比较两种植物在不同资源下补偿反应的特点,可认为因休眠芽位置及其活动方式不同而所造成的体型差异对植物的补偿反应式样有很大影响。

Identifying mechanisms of tolerance to herbivore damage will facilitate attempts to understand the role of tolerance in the evolutionary and ecological dynamics of plants and herbivores. Several external factors, such as water availability, nutrient availability, intensity of damage, and timing of damage, will affect the ability of individual plants to tolerate damage by mediating internal mechanisms. Though interspecific comparisons are useful for identifying possible mechanisms, direct comparisons between tolerance and putative mechanism have been made almost exclusively in interspecies or interpopulation studies. This study compared the compensatory responses of Arena sativa and Brassica campestris, which belong to different growth forms, to clipping under two fertilization treatments. The results showed that, for Arena sativa, under no fertilization treatment, the biomass, total biomass, fruit weight and number of fruits were greater than in the control, but only some aspects resulted in overcompensation. Under fertilized conditions, clipping treatments did not cause any overcompensation. Whether fertilized or not, the index of compensation during the tillering stage and jointing stage were both higher than during the flowering stage. Thus, under the no fertilization treatment, the low clipping treatment during the vegetative stage was shown to benefit Arena sativa. With respect to Brassica campestris, the index of compensation was greatest in the low clipping treatment during the flower bud stage, and was enhanced under fertilization. These results indicate that clipping during the reproductive stage can help compensatory, growth in Brassica campestris. The different responses to clipping were attributed to the different growth forms, which had different positions and activities of dormant buds.