‘黄金水蜡’不同叶色叶片的生理生化与超微结构研究

Study on Physio-biochemcal Indexes and Ultrastructure in‘Golden Wax’Leaves with Different Colors

为明确‘黄金水蜡’(Ligustrum obtusifolium)不同叶片叶色的生理差异,以‘黄金水蜡’的全黄叶、半黄叶、全绿叶3种叶色表型叶片为试验材料,测定叶片不同时期的叶色参数、色素含量、叶绿素前体物质含量及叶片叶绿体超微结构,旨在阐明叶片色素含量和解剖结构对叶色的影响。结果表明:在整个生长发育过程中,‘黄金水蜡’叶色参数变化的时序性较强,与叶色表型的变化情况相符合;半黄叶、全黄叶的类胡萝卜素与总叶绿素的比值均显著高于全绿叶(P<0.05);与全绿叶相比,半黄叶和全黄叶的叶绿素合成前体物质含量显著降低(P<0.05);半黄叶和全黄叶的叶绿体结构存在不同程度的缺陷,类囊体片层系统严重退化,缺少正常的基质类囊体和基粒类囊体,类囊体膜降解为残存的膜结构和囊状小泡。研究结果表明‘黄金水蜡’属于总叶绿素及叶绿素b合成减少型突变体,表现为半黄叶与全黄叶的叶绿体发育停滞,类囊体结构异常,叶绿素前体物质含量减少,导致叶绿素严重缺失,类胡萝卜素含量相对升高,是‘黄金水蜡’叶片呈现不同颜色的主要因素。

In order to clarify the physiological differences associated leaf colors in‘golden wax’(Ligustrum obtusifolium)leaves,the leaves of‘golden wax’with three colors(yellow,semi-yellow and full green)were used as experimental materials.Leaf color parameters,content of pigment and chlorophyll precursor,and the chloroplast ultrastructure of the three color leaves were measured to observe the effects of leaf pigment content and anatomical structure on leaf colors.The results showed that:during plants growth and development process,the temporal variation of leaf color parameters of‘golden wax’was strong,which was consistent with the change of leaf color phenotype;the ratios of carotenoids content to total chlorophyll content in semi-yellow leaves and full-yellow leaves were significantly higher than that in full-green leaves(P<0.05).Compared with the whole green leaves,the content of chlorophyll precursors in semi-yellow and whole yellow leaves was significantly reduced(P<0.05).The chloroplast structure of semi-yellow leaves and whole yellow leaves had different degrees of defects.The thylakoid lamellar system was seriously degraded,lacking normal matrix thylakoids and grana thylakoids.The thylakoid membrane was degraded into residual membrane structure and cystic vesicles.The results indicated that‘golden wax’was a mutant with reduced synthesis of total chlorophyll and chlorophyll b,in which the chloroplast development of semi-yellow leaves and full-yellow leaves was stagnant,the thylakoid structure was abnormal,and the content of chlorophyll precursor was reduced,resulting in serious loss of chlorophyll and relative increase of carotenoid content,which was the main reason for the difference in leaf color formation of‘golden wax’leaves.