干旱区生态环境知识资源中心(Arid): 种子萌发对策：理论与实验

Arid

	种子萌发对策：理论与实验
其他题名	Seed germination strategy: theory and practice
	李良; 王刚
来源期刊	生态学报
ISSN	1000-0933
出版年	2003
卷号	23 期号:6 页码:1165-1174
中文摘要	植物种子的萌发／休眠现象有复杂的原因和机制，综述了理论生态学家的研究结果。应用的理论基础是最优化理论和进化稳定对策（ESS）理论。当环境条件随机波动，种群受非密度依赖因素调节时，采用最优化理论的两头下注对策预测休眠一定会得到进化且萌发率与环境条件直接相关。环境条件稳定时采用进化稳定对策理论可得到在亲属竞争，种子扩散，基因冲突等等因素影响下的进化稳定休眠／萌发率，预测了休眠／萌发与它们之间的相互关系。以上各种环境条件影响种子萌发行为的方式可以表述为若种子立即萌发会遭遇到不良环境使适合度下降，那么就会推迟萌发，出现休眠，形成土壤种子库。萌发率应使种群适合度最优或具有进化稳定性。一些实验也部分验证了理论预测。
英文摘要	The mechanisms of seed dormancy have attracted a lot of research due to the complex interpretation of this problem. This paper focuses on how theoretical ecologists explain dormancy by using models. Using optimal theory, they developed the bet-hedging strategy. By randomly varying the environment, a population of desert annual plants would reach maximum fitness when the seed germination fraction was approximately equal to the probability that a year will be good for the survivorship and reproduction, given that there was adequate rain for germination. The evolution of dormancy was inevitable and can reduce the variance of fitness. Field work does support the model to some extent, but germination fraction in the field was always lower than prediction. This is maybe a limitation of optimal theory. Using evolutionary stable strategy (ESS) , scientists developed more models, most of which are cited in this paper. Most of them assumed the population was in a stable environment. Under these conditions the interaction among plants was greater than in the randomly varying environment, in which the relationship between plants and environment was the main effect. Using this model i they predicted the ESS germination or dormancy rate under conditions of seed dispersal, sib competition, gene conflict. Considering seed dispersal, if the dispersal distance was far enough, dormancy was not always necessary and all seeds can germinate. When dispersal distance was less than critical point, there was trade-off between dispersal and dormancy. If this phenomenon was caused by competition (the dispersal seeds will face less competition), any way that can reduce competitive strength will be favored by selection to increase germination fraction and then fitness, for example, thick seed coat or outcross mating system. There are some experiments that support these predictions. From another point of view. dormancy can be explained by compromise of genes or parent-offspring conflict. For example, if two genes controlled two traits expressed in young individuals and mature individuals respectively, the young ones favor faster germination than the adult ones. This conflict between the tow genes decided the germination strategy and led to a joint ESS. Similarly, the parents favored faster germinating than the offspring. Many factors influence germination strategy and with them, the germination fraction would change correspondingly. When seeds encountered a "bad environment", delayed germination would happen, and evolution of dormancy would occur. Germination fraction has the capacity to make population sustainable, have optimal fitness or develop stably.
中文关键词	萌发 ; 两头下注对策 ; 进化稳定对策 ; 最优化理论
英文关键词	germination bet-hedging evolutionarily stable strategy (ESS) optimal theory
语种	中文
国家	中国
收录类别	CSCD
WOS类目	ECOLOGY
WOS研究方向	Environmental Sciences & Ecology
CSCD记录号	CSCD:1268682
来源机构	兰州大学
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/204284
作者单位	兰州大学, 干旱农业生态国家重点实验室, 兰州, 甘肃 730000, 中国
推荐引用方式 GB/T 7714	李良,王刚. 种子萌发对策：理论与实验[J]. 兰州大学,2003,23(6):1165-1174.
APA	李良,&王刚.(2003).种子萌发对策：理论与实验.生态学报,23(6),1165-1174.
MLA	李良,et al."种子萌发对策：理论与实验".生态学报 23.6(2003):1165-1174.