摘要
大针茅(Stipa grandis P.Smirn.)是我国北方典型草原上的建群种或优势种植物,具有重要的饲用价值。大针茅根系能够形成丛枝菌根(arbuscular mycorrhiza,AM)。采集围栏区的大针茅根系,根据18S r DNA序列鉴定大针茅根系中的AM真菌为球囊霉属(Glomus)的根内球囊霉(G.intraradices)。通过对轻度放牧区、中度放牧区、重度放牧区和未放牧的对照区(30年围栏草场)大针茅根系AM真菌侵染情况的分析,发现不同放牧强度下菌丝侵染率和总侵染率都不存在显著性差异。放牧利用总体降低了丛枝的侵染率。放牧强度影响AM真菌泡囊结构在大针茅根系中的发育,轻度和中度放牧促进AM真菌泡囊的形成,而重度放牧则显著抑制。放牧强度对大针茅AM真菌的影响主要体现在AM真菌营养的交换和繁殖方面,AM真菌光合产物的减少属于中性反应,对碳的需求相对较少,这可能也是大针茅具有较强耐牧性的原因之一。
Stipa grandis as a constructive or dominant species on the typical steppe of Northern China, had a very important feeding value. The roots of Stipa grandis could develop a kind of arbuscular mycorrhiza(AM). The arbuscular mycorrhiza fungi(AMF) of S. grandis was identified as Glomus intraradices by analyzing 18 S r DNA sequence of AMF with root samples of S. grandis in fence protecting area(control). The infection of AMF was compared under 4 different grazing intensities(light, moderate, heavy and control). The results showed that there was no significant difference in the mycelium percentage and total infection percentage among 4 different grazing intensities. But the grazing generally decreased infection rates of AMF. Furthermore, light and moderate grazing promoted the development of vesicles of AMF, but heavy grazing inhibited it significantly. The different grazing intensities had different effects on reproduction of AMF and exchange of nutrients between S. grandis and AMF.Due to relatively less carbon demand for AMF, it belonged to medium reaction for AM in reducing the photosynthesis product. It could be one of the reasons of S. grandis performing a strong grazing tolerance.
出处
《基因组学与应用生物学》
CAS
CSCD
北大核心
2015年第4期769-774,共6页
Genomics and Applied Biology
基金
国家自然科学基金(31060057,31070414)
中国科学院西部之光“人才培养”项目
CAAS-ASTIP-IGR2015-01共同资助
