【作者】 殷爱华；

【导师】 韩素芬；

【作者基本信息】 南京林业大学 ， 森林保护学， 2004， 硕士

【摘要】 豆科植物能与根瘤菌形成共生固氮体系，但不是所有的豆科树种都能够结瘤，深入研究非结瘤豆科树种不能结瘤的原因不仅可为非结瘤豆科植物结瘤固氮提供理论依据，对进一步扩大根瘤菌共生寄主范围等研究也有一定的价值，本文即从部分豆科树种的染色体和凝集素两个方面探讨非结瘤豆科树种不结瘤原因，主要研究结果如下： 1．16种树种的盆播观察表明含羞草亚科(Mimosoideae)的3种树种和蝶形花亚科(Papilionoidae)中除了槐属的国槐(Sophora japonica)外的其余4种树种都能结瘤。苏木亚科(Caeselpinioideae)的8种树种都不能结瘤。并且结瘤树种的根系颜色一般都较浅，不结瘤的豆科树种根系的颜色均较深。 2．通过常规根尖压片法对18种豆科树种的染色体数目观察计数，表明豆科树种的染色体数目与其结瘤之间存在一定的关系。不结瘤的10种树种除望江南(Cassia occidentalis)染色体数是26条外，其余9种树种的染色体数目都是28条，是7的倍数；其中包括苏木亚科的8种树种和蝶形花亚科中的国槐(Sophora japonica)；而结瘤的8种树种包括含羞草亚科的四种树种——合欢(Albizia julibrissim)2n=2x=26、银荆(Acacia dealbata)2n=2x=26、肯氏相思(Acacia cunnihami)2n=2x=26、马占相思(Acacia mangium)2n=2x=26；蝶形花科的四种树种——马蹄针(Sophora davidii)2n=2x=18、紫穗槐(Amorpha fruticosa)2n=2x=40、刺槐(Robinia pseudacacia)2n=2x=22、木豆(Cajanns cajan)2n=2x=22，它们的染色体数目都不是7的倍数，且这8种树种都能结瘤。 3．选取的18种树种都是二倍体，由于药物的作用，在根尖压片中也出现极少数的混倍现象。 4．对马蹄针和伞房决明的染色体进行核型分析，马蹄针核型为K(2n)=2x=18=14m(8SAT)+4sm，核型类型属2A型：伞房决明核型K(2n)=2x=28m(4SAT)，核型类型属1A型。它们都属于较原始的类群，相比之下，伞房决明更原始一些。 5．通过6种豆科树种凝集素与13种根瘤菌胞外多糖的结合反应，表明凝集素与根瘤菌胞外多糖的结合，这是豆科与根瘤菌建立共生体系的一个前提条件，能与根瘤菌胞外多糖发生结合反应豆科树种，并不一定能结瘤。更多还原

【Abstract】 As we all know, not of all leguminous trees can fix nitrogen. It’s important in theories and uses to study on why some species of leguminous trees can not be nodulated. This study can bring the theories base of making un-nodulated legume trees be able to nodulate., as well as be favor to the study on the relationship of rhizobia with their hosts .The study is on the reasons why some species of leguminous trees can not be nodulated on the trees’ chromosome and lectin. The main result are as follow:1. 3 species of leguminous trees in Mimosoideae are nodulated,4 species of leguminous trees in Papilionoidae are nodulated, Sophorajaponica in Papilionoidae is un-nodulated,9 species of leguminous trees in Caeselpinioideae aren’t nodulated.The color of the nodulated leguminous trees’roots is lighter from light yellow to yellow than that of un-nodulated leguminous trees from light brown to black.2. According to the counting the chromosome numbers of 18 species of leguminous trees, the number of chromosome of leguminous trees has relation with whether the leguminous trees are nodulated or not in some degree.The chromosome numbers of 10 species of un-nodulated leguminous trees which expect for Cassia occidentalis are all 28 which is divided intergrally by 7. The chromosome numbers of Cassia occidentalis is 26.and un-nodulated. Each of the chromosome number of 9 species of leguminous trees which can be nodulated is not 28 and is not divided intergrally by 7. These chromosome numbers all are not divided intergrally by 7.3. All of the chromosome of 18 species of leguminous trees are diploid, but because of the function of the pretreatment, there are few cells that have tetraploid chromosome in roots squash of leguminous trees.4. Karyotype analysis indicate that caryotype formula of Sophora davidii is K (2n) =2x=18=14m (8SAT)+4sm. Karyotype formula of Cassia canymbosa is K (2n) =2x=28m(4SAT) . Cassia canymbosa is more original than Sophora davidii.5. The reaction of lectins with rhizobium is the pre- condition of founding the relationship of symbionic nitrogen fixation. Some leguminous trees can recognize rhizobium but still can not be nodulated.更多还原