中国疣粒野生稻的分布、濒危现状和保护前景

继1978-1982年全国野生稻普查后，又一次对中国疣粒野生稻（Oryza granulata (Nees et Arn.Ex Watt.））主要分布点的居群特征、濒危现状和破坏情况进行了野外生态学研究。由于行政区划的改变，目前疣粒野生稻在中国分布的市（县）达30个。它在群落盖度为90%-210%下生长良好，具有抗旱和适应中度干扰的能力。聚集参数分析表明在群落中居群以集群分布为主。该物种主要通过重力和动物传播种子，居群间的基因流有限，形成了典型的集合种群（metapoulation）结构。生境丧失对疣粒野生稻的生长造成非常严重的后果，巳有12.9%的疣粒野生稻居群灭绝，83.9%的居群处于中度和重度的干扰之下。由于各地区的破坏程度不平衡，目前疣粒野生稻的分布被压缩到海南省的西南部山区和云南省和澜沧江中下游、南汀河流域，面临热区开发的巨大威胁。研究中建立了中国疣粒野生稻的总DNA库，作为易位保护的手段之一和开展保护遗传学研究的基础；并讨论了居群遗传结构与居群分布格局之间的相互关系和保护中需注意的问题。

Distribution and Conservation of an Endangered Wild Rice Oryza granulata in China

Nearly Twenty years after the first large-scale field survey on wild rice in China during 1978-1982, we have recently made an extensive survey on Chinese Oryza granulata (Nees et Arn. Ex Watt.), including its current distribution, population characteristics and status of endangerment. Because of the change in the division of administrative areas, the number of counties or cities where the wild rice grows has reached up to 30. Oryza granulata grows normally under the coverage of 90%-210% in the tropical forest with resistance to drought and moderate disturbance. The measurement of aggregation showed that it maintains a colony pattern in the community. Oryza granulata scatters seeds mainly by gravity and animals, causing limited scale of gene flow between local populations and attaining a typical metapopulation structure of the distributional pattern. Our survey revealed that 12.9% of the populations had been extinct, and 83.9% were endangered. The extent of disturbance varied in different areas. Up to date, the majority of the populations grow in the mountainous areas of southwestern Hainan and drainage area of Nanding river, Lancang river of Yunnan, under the threat of human activity. A total DNA bank was established that consists of 1?109 individuals from 49 populations. In the practice of conservation, difficulties such as lacking immediate utility and scattered distribution impeded the conservation efficient. However, owing to its characteristics of population genetics, sustainable and ex situ conservation strategies are appropriate in some places to salvage this important rice germplasm.