高寒草甸主要植物种群繁殖对策的研究

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	高寒草甸主要植物种群繁殖对策的研究
	邓自发
学位类型	硕士
导师	周兴民
	1994
学位授予单位	中国科学院西北高原生物研究所
学位授予地点	中国科学院西北高原生物研究所
学位专业	植物生态学
关键词	高寒草甸植物种群繁殖对策繁殖效力
摘要	本文对生殖生态学和繁殖对策的研究历史和现状作了概述，分别从植物种子生产状况、土壤种子库、种子萌发、营养繁殖（芽的萌生）和繁殖效力等方面探讨了高寒草甸主要植物群（矮嵩草种群、小嵩草种群、藏嵩草种群和垂穗披碱草种群）的繁殖对策。研究结果表明：1．单位面积（米~2）上小嵩草种子产量最高；藏嵩草每穗种子数量最多；矮嵩草有效穗比例最高；藏嵩草种子千粒重最高，另两种嵩草种子千粒重相近。三种不同生境中生长的垂穗披碱草种群种子产量相差较大，但是它们种子千粒重相等，即不同生境中垂穗披碱草种子和生产的可塑性是通过调节每穗种子数来实现，而不是变化种子大小和重量来完成的。2．矮嵩草草甸和小嵩草草甸土壤种子库都较大，藏嵩草草甸的较小；矮嵩草、藏嵩草和垂穗披碱草种子在土壤种子库中所占比例较小，小嵩草的较高。四种植物种子在生长季结束后都基本成熟，不存在后熟过程，无内在休眠期，在适宜的温度和充足的水分供应条件下矮嵩草种子萌发率较高，另两种嵩草种子萌发率较低，垂穗披碱草种子萌发速度很快，且萌发率高达95％左右；种皮是影响嵩草种子发芽的主要原因。3．根据嵩草无性系种群中无性系小株的年龄分布，可以推测三种嵩草的寿命为4－5年；藏嵩草无性系种群中新芽形成能力最强，芽所占比例最高；芽主要是在二龄营养株的叶鞘内萌生，部分生殖株叶鞘内也有芽产生；I型生境中垂披碱草种群营养繁殖能力最强，芽所占比例最大，III型种群相应能力最差。4．矮嵩草和小嵩草的繁殖效力较高，藏嵩草和垂穗披碱草的较低；三种嵩草总繁殖效力中营养繁殖效力占绝对优势，垂穗披碱草总繁殖效力中营养繁殖效力和有性繁殖效力所占比例相当；三种嵩草在高寒生境中主要采用营养繁殖对策，而垂穗披碱草采用营养和有性两种繁殖方式维持和扩大其种群。
其他摘要	This paper summarizes the studing history and present situation of reproductive ecology and reproductive strategy, and inquires into the reproductive strategies of main plant populations (Kobresia humilis, K. pygmaea, K. tibetica and Elymus nutans) of alpine meadow from plant seed production soil seed banks, germination, vegetative reproduction (buds) and reproductive effort respectively. The results show that: 1. In three Kobresia species, K. pygmaea has the highest seed output per unit(m~2); the seed number per ear of K. tibetica is maximum; K. humilis has the highest rate of efficacious ears; the weight of 1000 seeds of K. tibetica is maximum, which of K. humilis and K. pygmaea are equal. There is large difference in seed output of E. nutans in three different environments, but their weight of 1000 seeds are equal, so the plasticity of seed production of E. nutans in different environment is not realized by changing seed size and weight, but regulating seed number of per ear. 2. The soil seed banks of K. humilis meadow and K. pygmaea meadow are larger than that of K. tibetica meadow; the proportion of seed number of K. pygmaea in total seed number of the soil seed bank is highest in four species. All of four species seed have been ripe at the end of growth-season, and there are not after-ripening and initial dormancy. Provided with the appropriate environmental conditions (i.e. temperature and water), the germinate rate of K. humilis seed is higher than that of other two Kobresia species; the speed of germination of E. nutans is very rapid and the germinate rate get to about 95%; seed coat is the main reason that effect the seed germination of Kobresia species. 3. According to the age distribution of ramets of Kobresia species clonal populations, we can estimate the life-spans of three Kobresia species are 4-5 years; buds mainly producte in two-year old vegetative tillers and parts of reproductive tillers; in three type environment, the capability of vegetative reproduction of E. nutans in I-type environment is maximum, and that in III-type environment is minimum. 4. The reproductive efforts of K. humilis and K. pygmaea are higher than that of K. tibetica and E. nutans; the proportions o vegetative reproductive efforts are more than that of sexual reproductive efforts in total efforts of three Kobresia species, but out of total reproductive effort of E. nutans, the proportion of vegetative reproductive effort and that of sexual reproductive effort are close. So under alpine environmental conditions, three Kobresia species mainly depend on vegetative reproductive strategies to maintain and enlarge their populations, but E. nutans depends on both vegetative and sexual reproductive strategies.
页数	68
语种	中文
文献类型	学位论文
条目标识符	http://210.75.249.4/handle/363003/3326
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	邓自发. 高寒草甸主要植物种群繁殖对策的研究[D]. 中国科学院西北高原生物研究所. 中国科学院西北高原生物研究所,1994.

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