Development of the viviparous hypocotyl of mangrove and its adaptation to inter-tidal habitats:A review
- 生命科学－已发表论文 
[中文文摘]热带亚热带海岸潮间带的高盐、淹水、土壤缺氧和潮水冲击等不良环境因子导致了红树植物在形态、生理和生态方面的特异性 ,尤其是其独特的胎生现象。从红树植物胎生繁殖体在母体的发育过程和繁殖体落地后对潮间带生境的适应两个角度探讨了红树植物胎生现象的适应意义。红树植物的胎生现象是对潮间带盐胁迫、淹水、土壤缺氧和潮水冲击等综合生境的适应 ,而不是单独其中一种胁迫因子的适应。红树植物胎生繁殖体在母体的发育过程中通过能量积累、渗透调节、形态完善等过程为掉落以后适应潮间生境做准备 ,掉落的胎生繁殖体依靠从母体获得的能量和营养克服潮间带的盐胁迫、淹水、土壤缺氧和潮水冲击等多重胁迫。红树植物胎生繁殖体落地后的能量收支平衡是决定繁殖体定居成功与否的关键 ,而胎生现象的意义正是通过胎生繁殖体在母体发育过程中积累足够的能量和营养来适应潮间带生境。红树植物胎生繁殖体落地后苗木在潮间带滩涂的生长发育过程中存在一个能量“阈限”,能阈的高低决定于潮间带生境的恶劣程度 ,而突破能阈能力决定于胎生繁殖体所携带的能量与营养的数量。这为红树林湿地恢复提供了理论基础 ,但还需要更多的证据来支持该理论.[英文文摘]Mangroves are a diverse group of predominantly tropical trees and shrubs growing in the marine intertidal zone where conditions are usually harsh , restrictive and dynamic. The peculiarities of the mangrove intertidal habitat causes the peculiarity of its structure, physiology and ecology . The vivipary of mangroves is one particular feature which is the result of long-term adaptation to the inter-tidal environment. The adaptive significa nce of vivipary to mang rove plants was reviewed from two aspects: propagule development while still attached on the mat ernal plants and adaptation to inter-tidal environments of propagules after release . Vivipary in mangrove plants is an adaptation to the integ rat ed stresses of salt, water logging and tide,but not any single stress. During t he development of vivipar ous propag ules while still attached to maternal plants, they accumulate energy , nutrients and osmotica and perfect their structure, adaptating them to t he intertidal environment after release. The viviparous propagules depend on the energy and nutrients accumulated from maternal plants to cope with salt and waterlogging stresses. The success or not of the ecesis of vivipar ous propagules depends on the balance of energy income and expenditure . The significance of vivipary in mang rove plants is to accumulate enough energy and nutrients to cope with the intertidal environment. A “t hr eshold”hypothesis is put forw ard in this paper . According to this hypothesis, there is a threshold of energy during growth and development of the viviparous propagules in the intertidal environment . The height of the threshold depends on t he degree of environmental stress, such as water salinity, w aterlogging duration and photo synthetic illuminat ion. The ability to climb above the threshold depends on storing sufficient quantity of energy and nutrients in viviparous propagules. This threshold hypothesis calls for more direct evidence .