大果卫矛和欧洲卫矛叶片呈色机制研究

Studies on the Color Mechanism of Euonymus myrianthus and Euonymus europaea

以大果卫矛和欧洲卫矛为试验材料,采用扫描电镜观察两者叶片的结构,并测定叶色相关的生理指标,探讨各项指标的变化规律和内在联系,以期为卫矛属植物的开发和应用提供依据。结果表明,2种植物叶片的表皮特征和横切面结构相似,叶片内不存在圆锥形细胞和气室。2种植物叶片的光合色素含量在转色期均呈下降趋势,但大果卫矛的叶绿素含量下降幅度明显小于欧洲卫矛。大果卫矛的花色素苷含量以及各类色素含量占比变化不大,欧洲卫矛花色素苷大量合成且占比不断变大。欧洲卫矛的可溶性糖含量呈先上升后下降的单峰曲线,大果卫矛的淀粉含量前期有所下降,后期保持平稳。大果卫矛的苯丙氨酸解氨酶(PAL)和查尔酮异构酶(CHI)活性保持平稳,过氧化物酶(POD)和多酚氧化酶(PPO)活性呈下降趋势。欧洲卫矛CHI和PPO活性呈先上升后下降的单峰曲线,POD活性呈下降趋势,PAL活性变化没有规律。综上,2种植物的叶色变化由叶片内色素的比例决定,而叶片结构对两者的呈色没有影响,可溶性糖参与花色素苷的合成,POD和PPO抑制花色素苷的合成。

With the perennial seedlings of Euonymus myrianthus and Euonymus europaea as experimental materials,leaf structure was observed by scanning electron microscopy and related physiological indexes of leaf colors were determined during different periods.We explored the changing laws and internal relations of various indicators,in order to provide a basis for the development and application of Euonymus.The results showed that the epidermal characteristics and cross-sectional structure of the leaves of the two species were similar,and there were no conical cells and gas chambers in the leaves.The photosynthetic pigments content of the two species showed a downward trend during the color change period,but the chlorophyll content of E.myrianthus decreased significantly less than that of E.europaea.The anthocyanin content of E.myrianthus and the proportion of various pigments did not change much.The anthocyanin of E.europaea was synthesized in large quantity and its proportion increased.The soluble sugar content of E.europaea increased first and then decreased.The starch content of E.myrianthus decreased in the early period and remained stable in the later period.The activity of phenylalanine ammonia lyase(PAL) and chalcone isomerase(CHI) of E.myrianthus remained stable,and the activity of peroxidase(POD) and polyphenol oxidase(PPO) showed a downward trend.The activity of CHI and PPO of E.europaea showed a unimodal curve of rising and then decreasing,the activity of POD showed a downward trend,and the activity of PAL changed irregularly.In summary,the leaf color change of the two species was determined by the proportion of pigments in the leaves,while the leaf structure had no effect on the coloration of the two species.Soluble sugar was involved in the synthesis of anthocyanin,but POD and PPO inhibited the synthesis of anthocyanin.