高寒退化禾本科混播草地地下芽库特征与群落持续性初探

为探明多年生不同混播组合草地退化后的群落稳定性和可持续性，本研究以祁连山金强河地区22年前建植的6种混播草地为研究对象，对草地群落结构及地下芽库构成进行调查分析。结果表明：4组分混播草地能够较好的保留建植种的地下芽，且以建植种分蘖芽为主，而3组分混播草地地下芽主要由侵入种的分蘖芽、根茎芽、根颈芽和根蘖芽构成，建植种芽密度占比较低；分蘖芽密度与建植种植物盖度、密度和地上生物量正相关，根茎芽、根颈芽、根蘖芽密度与侵入种植物盖度、密度和地上生物量正相关。其中，混播组合“冷地早熟禾(Poa crymophila)+多叶老芒麦(Elymus sibiricus)+无芒雀麦(Bromus inermis)+扁穗冰草(Agropgyron cristatum)”草地地下芽结构最优，可适当延长混播草地使用年限，是适宜青藏高原高寒地区的混播草种组合。

Characteristics of Underground Bud Bank and Community Persistence in Alpine Degraded Gramineous Mixed Sowing Grassland

To investigate the community stability and sustainability after the degradation of different perennial mixed sowing combinations,we investigated and analyzed the community structure and underground bud bank composition of six kinds of mixed sowing grassland established 22 years ago in Jinqianghe area of Qilian Mountains. The results showed as follows:In the 4-component mixed-planting grassland,the bud bank of the establishment species was better preserved,and the bud density of the establishment species was mainly tiller buds. However,the underground bud bank of the 3-component mixed-planting grassland was mainly composed of tiller buds,rhizome buds,root-derived buds,and crown buds of the invasive species,and the proportion of bud density of establishment species was low. The density of tiller buds was positively correlated with coverage,density,and aboveground biomass of establishment species,while the density of rhizome buds,root-derived buds,and crown buds were positively correlated with coverage,density,and aboveground biomass of invasive species. Among them,the mixed sowing combination "Poa crymophila+Elymus sibiricus+Bromus inermis+Agropgyron cristatum" was the best underground bud structure,and could prolong the service life of mixed grassland appropriately. Therefore,the mixed sowing combination was suitable for the alpine region of Qinghai-Tibet Plateau.