试论野生稻资源遗传多样性原生境保存

我国野生稻资源丰富,分布地域广阔,由于经济建设用地需要,近年来野生稻原生地遭到严重破坏,野生稻原生境保存已是十分紧迫的事情。本文论述了原生境保存的意义,原生境保存地的选择原则及设想,旨在提高全民生态保护意识,加强野生稻资源保护。     

中国野生稻原生境保护方法研究

在充分调查我国野生稻种质资源现状的基础上,分析了野生稻的濒危状况及其致濒因素,制定了野生稻原生境保护的选点原则,结合江西东乡、广东高州、云南元江和广西武宣等4个野生稻原生境保护示范点建设及各个保护点的社会、经济和环境条件,提出了围墙、围栏、植物篱笆和农民参与性等不同的保护方法,并就原生境保护点的开发性保护管理模式进行了探讨。     

我国北回归线区域普通野生稻遗传多样性和遗传结构研究

选择分布于水稻染色体组的26对SSR引物,对集中分布于广西来宾市北回归线附近的13个普通野生稻居群的342份材料进行遗传多样性和遗传结构研究。结果表明,该地区的野生稻无论在种内(A=9.154,Ae=4.446,I=1.547,He=0.671)还是居群水平上(P=95%,A=4.219,Ae=2.394,I=0.905,He=0.476)遗传多样性都十分丰富,高于同类研究水平。供试居群的遗传分化系数Gst为0.30,表明30%的遗传变异存在于居群间,大部分遗传变异存在于居群内。居群间的遗传一致度变化范围为0.332~0.903,且居群间地理距离越近,遗传一致度越高,说明北回归线附近的普通野生稻居群符合"隔离-距离"模型。综合上述研究结果和我国野生稻保护现状,建议对居群G13和G06实施优先保护。     

桂东南地区普通野生稻遗传多样性研究

利用25个微卫星位点对广西壮族自治区贺州、崇左、防城港3市8个居群301份普通野生稻材料的遗传多样性和遗传结构进行研究,结果表明桂东南地区普通野生稻遗传多样性丰富,平均等位基因数A=10.2400,有效等位基因数Ae=5.0221,平均期望杂合度He=0.7641,实际观察杂合度Ho=0.4840.根据固定指数(F=0.5653)计算出的异交率(t=0.2777)表明,普通野生稻的繁育系统是典型的混合繁育系统.对其遗传结构分析表明,总的遗传变异中有34.59%存在于居群间(Fst=0.3459).进一步研究发现大多数居群偏离了Hardy-Weinberg平衡且杂合体不足(Fis=0.2680,Fit=0.4817).最后根据各居群的遗传变异特点和遗传多样性比较,建议居群QT、YJ和TJ需要优先保护.     

云南澜沧县陆稻品种资源多样性和原生境保护

云南澜沧县不仅存在丰富的陆稻品种多样性和形态多样性,而且也存在陆稻生长环境和栽种管理方法的多样性,即山地民族在陆稻栽种方面的土著知识（indigenous knowledge,IK）多样性,讨论了由传统的刀耕火种生产制度过渡到现代固耕生产方式对陆稻生产及品种资源保存和保护的影响。提出了陆稻资源多样性保护的建议。     

中国野生稻资源考察、鉴定和保存概况

本综述了我国野生稻种质资源的考察收集、农艺性状鉴定、编目、繁种、入库保存等情况。到目前为止,我国收集了野生稻种资源近万份,编目7324份,种子入国家种质库长期保存5599份,种茎进国家野生稻圃长期保存8933份,显示出我国野生稻资源丰富的遗传多样性,并得到较完善的保存。介绍了鉴定选出的一批具有优良性状的种质资源。作还提出加强野生稻资源保护和研究的6点建议。     

广西普通野生稻资源遗传多样性初探Ⅰ普通野生稻资源生态系统多样性探讨

本文对"九·五"攻关项目收集的野生稻资源与过去收集的资源一起进行生态环境及现状调查研究,探讨其生态系统多样性.结果表明,广西普通野生稻存在3个生态系统,8个生态型.目前普通野生稻生态多样性受到严重破坏,长期妥善保存野生稻生态系统多样性刻不容缓.     

海南普通野生稻原生境土壤养分状况研究

为探明海南普通野生稻原生境土壤养分状况,采集了海南省不同地区普通野生稻和栽培稻土壤并进行养分测定。结果表明:海南普通野生稻原生境土壤pH、碱解氮总体适宜,全氮为极缺乏水平,有机质及其它养分含量以中等偏低水平居多。不同地区野生稻土壤除pH和全氮外,其它养分含量差异较大。在大多数地区,栽培稻土壤氮磷钾养分含量低于普通野生稻原生境。     

广西武宣濠江流域普通野生稻居群遗传多样性及保护研究

选用平均分布于水稻基因组的24对SSR引物,对沿河分布最长的广西武宣濠江流域的12个普通野生稻居群343份材料的遗传结构进行研究.结果表明:(1)该地普通野生稻遗传多样性丰富.24个位点共检测到206个等位变异,平均等位变异数A＝8.7083,有效等位变异数Ae＝3.7117;(2)该地普通野生稻居群具有较高的遗传分化和一定频率的基因流.群体遗传分化系数Gst＝0.2659,基因流Nm＝0.6901,表明26.59%的遗传变异存在于居群间;(3)SSR标记使普通野生稻居群中一些稀有等位变异得以显现.206个等位变异中,65个等位变异仅出现在1个或2个居群中,且频率较低,其中12个等位变异只出现在居群B中;(4)通过聚类分析和主坐标分析(PCO),下游居群A和B遗传关系较近,中游居群C比较独特,单独成为一类,中游居群D、E、F和G遗传关系较近,中游居群H、I和J及上游居群K和L遗传关系较近.根据上述分析结果,建议对濠江下游和中游具有代表性的居群(即居群B、D和H)的普通野生稻进行重点保护.     

云南省野生稻资源保存保护现状

1998年和1999年对云南省野生稻原生境进行考察,并结合云南野生稻的历史,阐述了云南野生稻的保护保存现状,云南野生稻原生境正在遭到严重的破坏,野生稻群体锐减,云南野生稻保护保存现状令人担忧.最后提出了保护保存云南野生稻资源的四点建议.     

Plant diversity in a changing world: status,trends, and conservation needs

The conservation of plants has not generated the sense of urgency—or the funding—that drives the conservation of animals, although plants are far more important for us. There are an estimated 500,000 species of land plants (angiosperms, gymnosperms, ferns, lycophytes, and bryophytes), with diversity strongly concentrated in the humid tropics. Many species are still unknown to science. Perhaps a third of all land plants are at risk of extinction, including many that are undescribed, or are described but otherwise data deficient. There have been few known global extinctions so far, but many additional species have not been recorded recently and may be extinct. Although only a minority of plant species have a specific human use, many more play important roles in natural ecosystems and the services they provide, and rare species are more likely to have unusual traits that could be useful in the future. The major threats to plant diversity include habitat loss, fragmentation, and degradation, overexploitation, invasive species, pollution, and anthropogenic climate change. Conservation of plant diversity is a massive task if viewed globally, but the combination of a well-designed and well-managed protected area system and ex situ gap-filling and back-up should work anywhere. The most urgent needs are for the completion of the global botanical inventory and an assessment of the conservation status of the 94% of plant species not yet evaluated, so that both in and ex situ conservation can be targeted efficiently. Globally, the biggest conservation gap is in the hyperdiverse lowland tropics and this is where attention needs to be focused.     

中国林木遗传资源原地保存状况分析

中国林木遗传资源原地保存体系包括以自然保护区为代表的区域保存、以原地保存林为代表的群体保存和以古树为代表的个体保存3种类型。截至2012年,全国有自然保护区2669个,面积14979万hm2,约占国土面积的14.94%。截至2011年,建立了森林公园2747处,总面积1703万hm2;建立了国家与省级风景名胜区共962处,总面积1975万hm2;截至2012年,在16个省建立了50多个树种的原地保存林和天然采种林群体;截至2005年,全国共清查出古树名木285.3万株,绝大部分进行了挂牌保护。全国约90%的陆地自然生态系统、85%的重点保护野生动物种群、65%的高等植物群落类型都得到了较好保护。中国林木遗传资源原地保存成绩显著,但也存在不足,今后应优先考虑如何提高原地保存的质量,解决保护区域与当地经济发展的矛盾,加强对原地保存的遗传资源动态监测和评价。     

Orchid conservation in China from 2000 to 2020: Achievements and perspectives

We review achievements in the conservation of orchid diversity in China over the last 21 years. We provide updated information on orchid biodiversity and suggestions for orchid conservation in China. We outline national policies of biodiversity conservation, especially of orchid conservation, which provide general guidelines for orchid conservation in China. There are now approximately 1708 known species of Orchidaceae in 181 genera in China, including five new genera and 365 new species described over the last 21 years. The assessment of risk of extinction of all 1502 known native orchid species in China in 2013 indicated that 653 species were identified as threatened, 132 species were treated as data-deficient, and four species endemic to China were classified as extinct. Approximately 1100 species (ca. 65%) are protected in national nature reserves, and another ~66 species in provincial nature reserves. About 800 native orchid species have living collections in major botanical gardens. The pollination biology of 74 native orchid species and the genetic diversity and spatial genetic structure of 29 orchid species have been investigated at a local scale and/or across species distributions. The mycorrhizal fungal community composition has been investigated in many genera, such as Bletilla, Coelogyne, Cymbidium, Cypripedium, and Dendrobium. Approximately 292 species will be included in the list of national key protected wild plants this year. Two major tasks for near future include in situ conservation and monitoring population dynamics of endangered species.     

Restoration of genetic diversity from soil seed banks in a threatened aquatic plant, <Emphasis Type="Italic">Nymphoides peltata</Emphasis>

Populations of a threatened aquatic plant, Nymphoides peltata, have rapidly degenerated under the influence of recent artificial changes in Lake Kasumigaura of Japan. To estimate the potential of soil seed banks for genetic restoration of the species, we used 10 microsatellite markers to analyze the genetic variation in adults and in seedlings that emerged from soil seed banks. About 187 leaf samples from the cultured stocks that were collected in 17 adult subpopulations in 1995 and 2000 and from three subpopulations that were newly discovered in 2002 were analyzed. As a result, only 18 genets could be identified, suggesting that clonal diversity of the adult population had already become extremely low. Genetic tests were performed on 430 seedlings from seed banks at six locations of natural lakeshores and three of the restoration sites that were artificially constructed in an attempt to assign them to the remnant adult population; many of the seedlings showed genetic variation different from the adults. Furthermore, the seedlings preserved seven alleles that had been lost from remnant adults. However, they had lower average numbers of alleles and heterozygosity levels (NA = 1.5–3.1, H _E = 0.146–0.487) than the remnant adults (NA = 3.5, H _E = 0.539) and showed high inbreeding coefficients, suggesting that the seed banks were produced by inbreeding. Thus, although the seed banks had a certain potential to restore genetic diversity, the fitness reduction in seed banks caused by inbreeding could affect the success of restoration based on seed banks.     

稻种遗传资源多样性的开发利用及保护

由于近年来栽培稻众多改良品种的育成和大面积推广,使之在很大程度上取代了地方品种,造成栽培稻基因源的大量基因流失,导致栽培稻品种的遗传基础越来越狭窄以至不能承受新病、虫害和不利环境的袭击。同时,由于人们长期施用杀虫剂、灭菌剂和除草剂等化学农药,严重地恶化了农业生态环境。要改变这种恶性循环的局面,开发和利用稻种的遗传资源,以丰富栽培稻品种的遗传基础是非常必要的。稻种基因源包括了亚洲栽培稻、非洲栽培稻、杂草稻、稻属的野生物种以及稻族内的近缘属种,它们是栽培稻品种进一步改良所不可缺少的遗传资源。但是,由于农业生产模式的改变,社会经济和工业化水平的迅速发展和提高,稻种基因源的多样性受到了严重的影响和威胁。一些野生稻种的居群已经迅速地缩小甚至从原产地消失。因此,对稻种基因源及其多样性进行及时有效的保护,并对其进行合理的开发和利用,是保证栽培稻进一步改良和持久生产的最有效方法。     

Discrimination and genetic diversity of cultivated and wild safflowers (Carthamus spp.) using EST-microsatellites markers

In spite of being one of the major oilseed crops, little is known about genetic diversity and relationships between species of safflower. In this study EST-SSR markers were used to evaluate and characterize 42 genotypes from six species including Carthamus tinctorius, Carthamus palaestinus, Carthamus oxyacanthus, Carthamus lanatus, Carthamus dentatus, and Carthamus boissieri. Thirty three primer pairs produced 123 polymorphic bands with 2–8 alleles per locus. The EST-SSR markers showed different level of gene diversity. The highest Polymorphism Information Content (PIC) values were observed for primers EL510507 and EL390720 (0.49 and 0.45, respectively). The highest genetic diversity and heterozygosity were observed for C. oxyacanthus. Both cluster and principal coordinate analysis (PCoA) clearly separated species into distinct groups. Within each species the accessions were clustered in different subgroups that mainly supported the known origins. The result showed that C. palaestinus had the most genetic similarity with cultivated safflower and C. oxyacanthus was next in this respect. In general, EST-SSR markers effectively revealed the genetic relationships and diversity of Carthamus species. This information is valuable for safflower improvement since C. palaestinus and C. oxyacanthus are both crossable with the cultivated species C. tinctorius.     

中国野生稻遗传资源的保护及其在育种中的利用

我国有三种野生稻,即普通野生稻(Oryza rufipogon)、药用野生稻(O.officinalis)和瘤粒野生稻(O.meyeriana)。这三种野生稻均被列为国家二级保护植物(渐危种)。调查结果表明,野生稻由于其自然群落大量丧失而濒危,濒危程度为普通野生稻>药用野生稻>瘤粒野生稻。造成濒危的主要原因是人为的破坏活动。人类的经济活动导致了野生稻生境丧失、生境质量不断恶化、栖息地越来越少;人类的活动也导致了外来种的入侵。目前,对野生稻的保护措施主要有就地保护(原地保护或原位保护)和迁地保护(易地保护或异位保护)。易地保护包括以种子保存的种质厍、以种茎保存的种质圃和以器官培养物作为材料的超低温保存。野生稻具有许多优良特性,如特强的耐寒性、高的抗病虫性、优质蛋白质含量高、功能叶片耐衰老的特异性、特强的再生性、良好的繁茂性及生长优势等等,这些优良特性已被广泛用于水稻常规育种和杂交育种中,并取得了巨大的社会效益和经济效益。有关野生稻生物技术方面的研究,如花药培养、原生质培养、体细胞杂交和基因工程等方面已取得了较大的进展。野生稻将在水稻育种中发挥越来越重要的作用。