放牧强度和短期休牧对青藏高原东部高寒草甸优势物种根系分泌速率的影响

发布时间：2018-04-22 02:03

本文选题：根系分泌物 + 放牧强度　；参考：《应用与环境生物学报》2016年04期

【摘要】：根系分泌物是调节土壤养分循环的关键物质,对土壤微生物生理活性和有机物分解等土壤生态过程有关键影响.为了解放牧条件下根系分泌物分泌速率和变化规律,在放牧管理试验样地上,采用原位草本根系分泌物收集法,在生长旺季测定不同放牧强度(不放牧、轻度放牧、重度放牧)和放牧停止后1 d和21 d取样(视为短期休牧)青藏高原高寒草甸优势物种垂穗披碱草(Elymus nutans)的根系分泌速率.结果显示:放牧条件下,垂穗披碱草在生长旺季正午的根系分泌平均速率(以C计)为851.29μg g~(-1) h~(-1).放牧停止后1 d,不放牧、轻度放牧和重度放牧的根系分泌速率无显著差异;而放牧停止后21 d,轻度放牧的根系分泌速率[(1 032.33±53.63)μg g~(-1) h~(-1)]和地上生物量增量显著高于不放牧,重度放牧则与不放牧差异不显著.本研究表明,轻度放牧和适当短期休牧能够增加根系分泌速率,并可能通过正反馈作用刺激植物地上补偿生长.
[Abstract]:Root exudates are the key substances to regulate soil nutrient cycling and play a key role in soil ecological processes such as the physiological activity of soil microorganisms and the decomposition of organic matter. In order to understand the secretion rate and variation of root exudates under grazing conditions, the collection of root exudates from herbaceous roots in situ was used to determine the different grazing intensities (no grazing, light grazing) in the grazing management experiment. The root exudation rate of ephedrine nutanss, a dominant species of alpine meadow in Qinghai-Tibet Plateau, was observed at 1 and 21 days after grazing. The results showed that under grazing conditions, the average root exudation rate (measured as C) was 851.29 渭 g / h at noon in the high growing season. There was no significant difference in root exudation rate between light grazing and heavy grazing one day after grazing, but at 21 days after grazing, root exudation rate [1 032.33 卤53.63 渭 g / g] and aboveground biomass increment were significantly higher than that of non-grazing. There was no significant difference between heavy grazing and non grazing. The results showed that light grazing and short term grazing could increase root secretion rate and stimulate plant growth compensatory growth on the ground through positive feedback.
【作者单位】：四川农业大学动物科技学院草学系;中国科学院成都生物研究所中国科学院山地生态恢复与生物资源利用重点实验室生态恢复与生物多样性保育四川省重点实验室;四川省草原科学研究院;重庆市畜牧科学院;九寨沟风景名胜区管理局;
【基金】：国家自然科学基金项目(31500346,31350110328) 四川省科技厅项目(2014HH0017,2015HH0025,2015JY0231,2016HH0082) 中国科学院“西部之光”项目和中国科学院成都生物研究所青年研究员项目资助~~
【分类号】：S812

【相似文献】