波罗蜜叶片突变体叶绿素含量测定和超微结构观察

波罗蜜（Artocarpus heterophyllus）是一种热带果树,至今对其突变体的研究少有报道。本研究以波罗蜜叶片为试验材料,探究其叶片出现白化和返绿现象的可能原因。（1）用分光光度计法、比色法测定波罗蜜叶片突变体和正常绿叶的叶绿素及叶绿素前体物质含量;（2）用叶绿素酶Elisa试剂盒测定叶绿素酶活性;（3）用透射电子显微镜对叶绿体的超微形态结构进行观察。研究结果表明：（1）不同叶色所产生的叶绿素a含量、叶绿素b含量、叶绿素总含量、类胡萝卜素含量均存在显著差异;（2）波罗蜜叶片突变体和正常绿叶的叶绿素合成前体物质含量之间并没有出现显著性差异;（3）对波罗蜜叶片的叶绿素酶活性进行测定时,发现其活性出现显著差异,但对其叶绿素含量的差异性并没有产生较大影响;（4）观察波罗蜜叶片内叶绿体超微形态结构时,发现正常绿叶的叶绿体形态完好且数量较多,白化叶和返绿叶的叶绿体内部结构存在缺陷,其原因是叶绿体基粒构建阶段受阻;基于测定波罗蜜叶片中的叶绿素、叶绿素前体物质含量和叶绿素酶活性,并观察波罗蜜叶片内叶绿体的超微形态结构,对得到的数据结果进行比较分析。本研究推测是在叶绿素合成阶段,原脱植基叶绿素合成叶绿素时受阻及叶绿体发不良导致波罗蜜出现白化和返绿现象,为今后进一步综合研究波罗蜜突变体提供理论依据。

Determination of Chlorophyll Content and Observation of Ultrastructure in Leaves of Mutants of Artocarpus heterophyllus

Artocarpus heterophyllus is a tropical fruit, and so far there are few reports on its mutants. In this study, the leaves of A. heterophyllus were used as the experimental materials to explore the possible reasons for the albinism and regreening of the leaves. The contents of chlorophyll and chlorophyll precursors in leaf mutants and normal green leaves were determined by conventional methods. The activity of chlorophyllase was determined by Elisa kit. The ultrastructure of chloroplast was observed by a transmission electron microscope. Chlorophyll a content, chlorophyll b content, total chlorophyll content and carotenoid content produced by different leaf colors were significantly different. There was no significant difference in the content of chlorophyll synthesis precursors between the mutant and the normal green leaves. In the determination of chlorophyll enzyme activity of the leaves, although there was a significant difference in its activity, it had no significant effect on the difference in chlorophyll content. When observing the ultrastructure of chloroplasts in the leaves, it was found that the chloroplasts in the normal green leaves were intact and had a large number, and the internal structure of chloroplasts in the albino leaves and the regreening leaves was defective, because the chloroplast grana construction stage was blocked. Based on the determination of chlorophyll, chlorophyll precursor content and chlorophyll enzyme activity in the leaves, the ultrastructure of chloroplast in the leaves was observed, and the data were compared and analyzed. In this study, it was speculated that during the chlorophyll synthesis stage, the blocked synthesis of chlorophyll by pchlide and the poor chloroplast development led to the albinism and regreening of A. heterophyllus, which would provide a theoretical basis for further comprehensive study of A. heterophyllus mutants.