小麦黄化突变体叶绿体超微结构研究

利用透射电镜对小麦自然黄化突变体及其突变亲本(西农1718)叶片细胞叶绿体的数目、形态及超微结构进行比较分析。结果发现:(1)3种不同黄化程度突变体的叶绿体分布、数目、形状及大小与突变亲本无明显差异;(2)突变体叶绿素含量为野生型58%的黄绿植株与其突变亲本叶绿体超微结构无明显差异,基质类囊体与基粒类囊体高度分化,基粒数目以及基粒片层数目较多;(3)突变体金黄和绿黄植株的叶绿素含量分别为野生型的17%、24%,其叶绿体超微结构与突变亲本明显不同,突变体的叶绿体发育存在明显缺陷,其中突变体金黄植株的叶绿体内无基粒、基质片层清晰可见,有淀粉粒,嗜锇颗粒较多,而突变体绿黄植株的叶绿体内有基粒,但明显少于突变亲本,且基粒片层较少,基质类囊体较发达。结果表明该黄化突变体叶绿体超微结构的改变,是由于叶绿素含量降低造成,推测,该黄化突变是由于叶绿素合成受阻导致的。

Chloroplast Ultra-structure of a Xantha Wheat Mutant

The chloroplast numbers,morphologies and ultra-structures in the leaves of a xantha wheat mutants etiolating naturally and its parent(Xinong1718) were comparatively examined by transmission electron microscopy.It was shown that the mutant plants with three etiolating degrees did not obviously differ in chloroplast distribution,number,shape and size from the mutant parent;(2) Yellowish-green plants whose chlorophyll content was 58% of the wild type did not obviously differed in chloroplast ultra-structure from the parent,but their stroma-thylakoids and granum-thylakoids were highly differentiated and their granum and grana lamellae were relatively plentiful;(3) The chlorophyll contents of the golden and greenish-yellow plants were separately 17% and 24% of that of the wild type and their chloroplast ultra-structures obviously differed from that of the parent and the chloroplasts of the mutant plants had clear developmental defect,the chloroplasts of golden plants containing no grana,obviously visible stroma lamellae,starch grains and plentiful osmiophilic granules and those of greenish-yellow mutant plants containing grana whose number was obviously lower than that in the chloroplasts of the parent and that had a fewer layers of stroma lamellae,and highly developed granum-thylakoids.The results indicted that the change in the chloroplast ultra-structure of the xantha wheat mutant resulted from lowered chlorophyll content and it was supposed that the etiolating mutation resulted from chlorophyll synthesis blockade.