摘要
以青藏高原东部高寒矮嵩草草甸常见种垂穗披碱草为研究对象,通过为期3年的野外控制实验,研究了生长季早期刈割(重度刈割:留茬1 cm、中度刈割:留茬3 cm及对照:不刈割)、施肥(施肥、不施肥)和浇水(浇水、不浇水)对垂穗披碱草生物量分配、根系可溶性糖质量分数及补偿生长的影响,探讨其补偿生长机制.结果表明:与不刈割相比,中度刈割后垂穗披碱草增加了生长分配,减少了繁殖分配,繁殖分配与生长分配及贮藏分配均呈显著负相关,生长分配与贮藏分配间呈显著正相关,同时根系可溶性糖质量分数随刈割强度的增加显著提高;地上生物量与地下生物量在刈割后均发生低补偿,且二者之间存在着正相关关系,植物根系可溶性糖贮藏量在刈割后发生了超补偿;施肥消除了刈割后垂穗披碱草生物量分配与不刈割处理间的差异,并显著增加了垂穗披碱草的补偿地上生物量,浇水对多数测量指标的影响不显著,只显著增加了垂穗披碱草根系可溶性糖质量分数.说明刈割后植物可以通过增加其生物量分配和营养物质贮藏的可塑性来适应恶劣的生存环境,实现补偿性再生长,同时会以牺牲一部分繁殖分配为代价,施肥能够减小刈割带来的负面影响,提高垂穗披碱草的补偿生长能力,但却依然不足以引起植物生物量发生超补偿效应,故应严格控制刈割强度.
A 3-year field manipulative experiment was conducted on Elymus nutans in a Kobresia humilis meadow of Qinghai-Tibet Plateau to study the effects of clipping (heavy clipped: stubbled 1 cm;medium clipped:stubbled 3 cm and control: unclipped), fertilizing (fertilized, unfertilized) and watering (watered, unwatered) on the biomass allocation, water-soluble carbohydrate content and compensatory growth at the early time of growing season, aiming at a discussion of the compensatory mechanism of Elymus nutans. The results showed that the growth allocation was increased while reproduction allocation was reduced after medium clipped state compared with the unclipped state, the reproductive allocation had significantly negative correlations with the growth allocation and the storage allocation, and the growth allocation had a significantly positive correlation with the storage allocation. Besides, with the increase of clipping intensity, the water-soluble carbohydrate content of roots was significantly increased. The aboveground and underground biomass occurred as under-compensated, while the water-soluble carbohydrate storage of roots occurred as over-compensated after clipping, and the compensation of aboveground biomass had a significantly positive correlation with the compensation of underground biomass. Fertilization eliminated the differences of biomass allocation between clipped and unclipped states, and increased the compensation of aboveground biomass. The effect of watering was not obvious on most measurable indicators, while only increased the water-soluble carbohydrate content of roots.The results above indicated that the adaptation abilities to the complex conditions of existence were inproved by means of increasing biomass allocation and storing nutrition plasticity, and the compensatory growth of plants would sacrifice parts of their reproduction allocation. Fertilization could reduce the negative effects of clipping, enhance the compensation ability of plants, but it was not enough to cause over-compensation of biomass. Therefore, the clipping intensity should be strictly controlled.
出处
《兰州大学学报（自然科学版）》
CAS
CSCD
北大核心
2013年第6期807-814,821,共9页
Journal of Lanzhou University(Natural Sciences)
基金
国家自然科学基金项目(31070382)
陕西师范大学研究生培养创新基金项目(2012CXS050)
关键词
刈割
施肥
浇水
垂穗披碱草
生物量分配
可溶性糖
补偿生长
clipping
fertilizing
watering
Elymus nutans
biomass allocation
water-soluble carbohydrate
compensatory growth
