生物多样性 ›› 2002, Vol. 10 ›› Issue (2): 213-218.doi: 10.17520/biods.2002028

• 论文 • 上一篇    下一篇

食果动物与被取食植物的相互关系:协同进化?

刘勇, 陈进*   

  1. 中国科学院西双版纳热带植物园,云南勐腊 666303
  • 收稿日期:2001-10-30 修回日期:2002-01-07 出版日期:2002-05-20

Frugivores and their food plants: have they coevolved?

LIU Yong, CHEN Jin *   

  1. Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences,Mengla,Yunnan 666303
  • Received:2001-10-30 Revised:2002-01-07 Online:2002-05-20

在种子传播过程中动植物是否存在协同进化关系一直是争论的焦点。有观点认为,植物通过食果动物对其种子的传播可能获得逃避种子捕食者、占据新的生境斑块和基因流动等好处,而动物通过消化果肉获得营养和能量作为回报,动植物彼此相互作用,进而可能建立协同进化关系。动植物之间还可能发生在种、属或科水平以上的多物种的多配协同进化,或者通过关键种的协同进化来带动其他食果动物和植物相关性状的进化。“果肉防御假说”则认为果肉原本是保护种子的防御组织,后来才进化成为吸引食果动物以促进种子传播的物质。然而,食果动物和植物一对一的协同进化的例证并不多见;适合种子萌发和生长的环境在时空上难以确定;食果动物和植物的进化速度不一致;植物与种子传播者的选择压力存在着高度的不对称和不平衡,加上环境因素的重要影响,这种选择压力受到极大的限制而有可能变得不显著。种子传播中动植物在进化意义上的关系尚需进一步研究。未来研究应对食果动物和植物关系的复杂性和多样性有足够的认识。通过对系统发育中相联系的不同种的动植物关系的比较研究来揭示动植物关系对物种分化的影响,有可能为检验食果动物和植物之间的协同进化关系提供新的证据。食果动物传播种子对植物群落动态变化的影响、动植物关系和生物多样性保护等仍将是该领域研究的热点。

Whether a coevolutionary relationship exists between frugivores and their food plants has been argued for 30 years. Plant seeds dispersed by frugivores provide many advantages to plants, which may include escaping from the parents where seed or seedling predators are disproportionately abundant, colonizing new habitat patches and increasing gene flow. Simultaneously, frugivores obtain nutritional   
and energetic rewards as a consequence of digesting fruit pulp. The unique attributes of these two partners may give rise to a coevolutionary relationship. This concept stimulated studies on this field in early years. Some studies suggested that "diffuse coevolution" between plants and their dispersers might exist, whi   
ch may occur at the level of genus or family. Alternatively, the relationship may be one of just functional equivalence with no relationship to traditional taxonomy. It is also suggested that the evolution of seed dispersal systems is mainly determined by a few key dispersers and plants, which may control the evolution of related traits of other species. The defense scenario hypothesis, however,   
suggests that fleshy pulp of fruits was produced originally as a kind of defensive structure to protect seeds, only later becoming traits to promote seed dispersal. In recent years, many studies have suggested that the selective pressure between dispersers and plants is rather weak. Suitable sites for seed germination and seedling establishment are temporally and spatially unpredictable. Evolutio   
nary rates of herbivores and their food plants are unequal. High unpredictability and asymmetry of interaction, coupled with an important influence of abiotic factors, means that the influences of mutual selection pressures between plants and seed dispersers are greatly constrained. The evolutionary interaction between frugivores and plants in seed dispersal should be re evaluated. Attention shou   
ld be paid to the complexity and the diversity of the relationship between frugivores and plants. Comparative studies on the systematics of related species to evaluate the possible influence from the interaction of plants and their frugivores upon the specification of species may provide powerful evidence for coevolution. Furthermore, the influences of frugivore plant interactions on ecological dynamics and conservation will continue to be a hot topic.

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