粉红珙桐叶片呈色相关生理特性的季节变化

以四川省珙县王家镇同一生境下不同季节的粉红与绿叶珙桐叶片为试材,对其色素含量、渗透调节物质含量及相关酶活性进行测定,分析其季节性变化规律,从生理角度探寻影响珙桐叶片呈色的关键因素,以期为粉红珙桐的选育和合理栽培提供理论依据和技术参考。结果显示:(1)粉红珙桐叶片花色苷含量在春夏秋季均极显著高于绿叶珙桐,在夏季时含量最低;粉红珙桐叶片总叶绿素含量在夏季和秋季极显著低于绿叶珙桐,从春季过渡至秋季过程中逐渐上升;两者的类胡萝卜素和类黄酮含量差异不明显且在季节间较平稳。(2)粉红珙桐叶片的可溶性糖和可溶性蛋白含量略高于绿叶珙桐,夏季时达到最高;其脯氨酸含量也高于绿叶珙桐,且从春季到秋季缓慢上升。(3)粉红珙桐叶片苯丙氨酸解氨酶活性(PAL)、苯基苯乙烯酮黄烷酮异构酶(CHI)和超氧化物歧化酶活性(SOD)都显著高于绿叶珙桐,过氧化物酶(POD)活性则相反;从春季到秋季过程中,两种珙桐叶片PAL活性先减弱后增强,其POD和SOD活性则先增强后减弱,但粉红珙桐CHI活性逐渐减弱,绿叶CHI活性则先上升后下降。(4)粉红珙桐叶片花色苷含量与叶绿素含量、可溶性蛋白含量以及CHI、POD和SOD活性呈显著负相关关系。研究表明,叶片花色苷含量的增加和叶绿素含量的减少是粉红珙桐呈色的决定因素,CHI、SOD和POD活性是调节花色苷降解速率的关键酶。

Seasonal Dynamic of Physiological Characteristics of Pink Davidia involucrata

With the leaves of pink and green Davidia involucrata in Gongxian as test materials, we measured the physiological indexes including the pigment, osmotic regulator and related enzymes, and analyzed the correlation. In order to provide the theoretical basis and technical reference for the breeding and rational cultivation of pink D. involucrata, the study investigated the key factors affecting the coloration of D. involucrata from physiological characteristics. The results showed: (1) the content of anthocyanin in pink plants was extremely significantly higher than that of green plants in spring, summer and autumn. Its content reaches its lowest in summer. The total content of chlorophyll of pink plants were extremely significantly lower than that of green plants in summer and autumn. The difference of carotenoid and flavonoid content was no significant, and their yearly changes were stable. (2) There was also no significant difference in soluble sugar and soluble protein content, its content reaches its lowest in summer. The proline content of the pink was significantly higher, slowly increasing with the seasonal change. (3) The activities of phenylalanine ammonia lyase (PAL), chalone isomerase (CHI), and superoxide dismutase (SOD) of pink plants were significantly higher than that of green plants. PAL, CHI and SOD played the role of decomposing chlorophyll and promoting anthocyanin synthesis, while the effect of peroxidase (POD) was opposite. The activity of PAL in two plants firstly weakened and then increased with the seasonal change, while the activities of POD and SOD were opposite. The activity of CHI of pink color plants gradually decreased, and the green ones increased and then decreased. (4) Anthocyanin was negatively correlated with chlorophyll, flavonoids, soluble proteins, CHI, SOD and PAL. In conclusion anthocyanin was the determining factor of leaf color change. CHI, SOD and POD were the main enzymes that regulated anthocyanin degradation rate.