长喙毛茛泽泻遗传多样性及其与繁育系统的关系

利用聚丙烯酰胺凝胶电泳技术测定了濒危植物长喙毛茛泽泻（ＲａｎａｌｉｓｍａｒｏｓｔｒａｔｕｍＳｔａｐｆ）及３个对照种冠果草［Ｓａｇｉｔａｒｉａｇｕａｙａｎｅｎｓｉｓｓｓｐｌａｐｐｕｌａ（ＤＤｏｎ）Ｂｏｇｉｎ］、武夷慈姑（ＳｗｕｙｉｅｎｓｉｓＪＫＣｈｅｎｅｔａｌ）、矮慈姑（ＳｐｙｇｍａｅａＭｉｑ）共６个自然居群的遗传多样性。自花受精和以营养繁殖为主的长喙毛茛泽泻维持较低的遗传多样性，预期杂合度和观察杂合度分别为００６４和０１０４。以自花受精为主的冠果草遗传多样性更低，预期杂合度和观察杂合度分别为００３９和００６７。异体繁育但以营养繁殖为主的武夷慈姑遗传多样性比长喙毛茛泽泻的高，预期杂合度和观察杂合度分别为０１１１和０１８３。以异体繁育为主和营养繁殖的矮慈姑遗传多样性在这４个种中最高，其预期杂合度和观察杂合度分别是０１５５和０２６９。４个种的内繁育系数Ｆ值全为负值。冠果草、长喙毛茛泽泻、武夷慈姑直至矮慈姑，其异交程度从几乎为零逐渐递增，而其遗传多样性指标也相应地增高。长喙毛茛泽泻的遗传多样性程度高于冠果草但冠果草并不濒危，因此遗传多样性较低并不是濒危的直接原因

Genetic Diversity and Its Relationship with Breeding System of Ranalisma rostratum

Genetic diversity among 6 populations of Ranalisma rostratum, Sagittaria guayanensis ssp lappula, Sagittaria wuyiensis and Sagittaria pygmaea were investigated by using the assay of vertical slab polyacrylamide gel electrophoresis.Endangered species R rostratum with inbreeding and great proportions of vegetative reproduction maintained lower level of genetic variation than the average of plant species.Its expected heterozygosity and observed herozygosity were 0 064 and 0 104 respectively. S guayanesis with inbreeding maintained very low level of genetic diversity.Its expected heterozygosity and observed heterozygosity were 0 039 and 0 066 respectively.The genetic diversity of S pygmaea with great proportions of outbreeding and vegetative reproduction was the highest among these four species.Its expected heterozygosity and observed heterozygosity were 0 155 and 0 269 respectively.The genetic diversity of S wuyiensis with outbreeding and great proportions of vegetative reproduction was higher than that of R rostratum .Its expected heterozygosity and observed heterozygosity were 0 111 and 0 183 respectively.The inbreeding coefficients of four species are all minus.Both the proportions of outcrossing and genetic diversity increase from S guayanensi,R rostratum,S wuyiensis to S pygmaea .This means that the endangerment of R rosratum is not directly caused by its absence of genetic polymorphism.