环境梯度变化对松嫩草地有毒植物影响的研究-生态学专业论文.docxVIP

东北林业大学博：【-|学位论文对瑞香狼毒叶表面的亚显微结构也一定的影响：叶表面角质层纹饰逐渐变得密集，气孔 东北林业大学博：【-|学位论文 对瑞香狼毒叶表面的亚显微结构也一定的影响：叶表面角质层纹饰逐渐变得密集，气孔 大小和气孔指数呈减少的趋势，这是有毒植物瑞香狼毒在结构上对土壤盐碱胁迫的一种 适应。而叶表皮细胞的形状、垂周壁式样、气孔器类型等无明显变化。 瑞香狼毒营养器官中有毒成分主要包括总黄酮和香豆素类物质，其中总黄酮含量叶 中最高，而香豆素类物质根中含量最高。 综上所述，松嫩草地的三大限制因子(放牧、水分和盐碱)对有毒植物的生长和 分布都有影响，其中放牧和干旱压力对有毒植物的生长和分布具有促进作用，尤其放牧 的影响更为明显。而土壤盐碱化对有毒植物的分布有明显的限制作用。所以，要抑制松 嫩草地有毒植物的泛滥趋势，首先是要加强草地管理，合理制定载畜量，坚决避免超载 放牧，同时根据气候变化，合理放牧，从而有效地解决松嫩草地生态环境恶化问题。 关键词： 有毒植物；松嫩草地；放牧梯度；水分梯度；盐碱梯度 AbstracfAbstract Abstracf Abstract Songnen grassland，onc of the most important base of the farming industry in China， has been damaged seriously in recent years due tO improper ultilization，undergoing serious deterioration，grassland regression and a heavy loss of high quality forage．On the other hand， the variety of poisonous plants becomes increasingly inundant，which can make livestocks susceptible tO poison and cause seriously economic loss．Obviously,it is very meaningful to study poisonous plants on Songnen grassland． The results of wild investigation showed： On Songnan grassland，there are plenty of poisonous plants，·belonging tO 32 Families，72 genuses，and 100 species，which possess respectively 37．2％in Family,21．49％in Genus and 12．9 in Species of the total plants quantities． The geographic distribution of poisonous plants in this area belong tO 39 species in Mofigolia flora，54 species in Changbai flora，43species in Huabei flora and 23 species in Daxinganling flora．Among them，ChangBai Montain flora and Huabei flora are dominant． From the angle of ecological environment，the species of Mesophyte and Shygrophyte are the majority．It also proves that Songnen glassland belongs to Meadow stepp． Grazing intensity has significiant effect on poisonou plants of the Songnen grassland．With grazing indensity increased，obvious changes of poinsonous plants are observed as below：1) High quality forage has decreased gradually,while the species and biomass of poisonous plant get increased greatly by means of biomass growth both