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对不同季节白三叶(Trifolium repens)不同叶龄叶片(幼叶、中叶和老叶)抗氧化酶(SOD、POD和CAT)活力、渗透调节物(可溶性糖、可溶性蛋白和游离脯氨酸)含量、MDA含量和叶绿素含量进行分析,揭示白三叶不同叶龄叶片对不同季节温度适应的生理调控机理和白三叶叶片短寿在维护匍匐茎生长中的生态作用。结果表明:(1)冬季低温生出的幼叶MDA含量较低,而叶绿素a、POD和SOD活力、可溶性糖和脯氨酸含量均最高;夏季高温生出的幼叶MDA和叶绿素b含量较高,而POD和SOD活力、可溶性糖和脯氨酸含量较低。白三叶幼叶具有较强的生理调控可塑性以适应冬夏季温度。(2)不同季节幼叶成长过程中,其生理调控模式相近,随叶片长大成熟,叶绿素含量和SOD、POD、CAT活力及脯氨酸和可溶性糖含量均增高,而MDA含量降低。(3)不同季节老化叶片生理特征相同,叶片中可溶性糖和脯氨酸含量趋于增高,CAT活力及MDA含量均下降。研究表明,抗氧化酶和渗透调节物通过维护氧自由基代谢和水分代谢平衡而在幼叶适应不同季节温度、叶片快速生长中起重要保护作用。不同季节叶片抗氧化能力下降和持续积累的脯氨酸、可溶性糖抑制光合作用可能是叶片衰老和短寿的诱因。不同季节匍匐茎上叶片的短寿、快速衰老可使匍匐茎将能量物质分配给其顶部,促进匍匐茎顶部幼叶萌生和匍匐茎的延伸生长及种群的扩散,其在维护白三叶植株持续生存中具有重要的调控作用。
The activities of antioxidant enzymes (SOD, POD and CAT), osmolytes (soluble sugar, soluble protein and free proline) in leaves of different leaf seasons (young leaves, middle leaves and old leaves) Content, content of MDA and content of chlorophyll in leaves of white clover to reveal the physiological regulation mechanism of leaf temperature at different leaf ages of white clover and the ecological role of white clover leaf stalks in maintaining stolon growth. The results showed that: (1) MDA content in young leaves was lower in winter and chlorophyll a, POD and SOD activities, soluble sugar and proline contents were the highest in summer; MDA and chlorophyll b were higher in summer, POD and SOD activity, soluble sugar and proline content is low. White clover leaves have strong physiological regulation of plasticity to adapt to winter and summer temperatures. (2) During the growth of young leaves in different seasons, the physiological regulation patterns were similar. With the growth and ripening of leaves, chlorophyll content, SOD, POD and CAT activities, proline and soluble sugar contents increased, while MDA content decreased. (3) The physiological characteristics of the aged leaves in different seasons were the same, the content of soluble sugar and proline in the leaves tended to increase, and the CAT activity and MDA content decreased. Studies have shown that antioxidant enzymes and osmolytes play an important protective role in adapting young leaves to different seasons temperature and rapid leaf growth by maintaining oxygen free radical metabolism and water metabolism balance. In different seasons, the antioxidant capacity and the accumulation of proline, soluble sugar inhibition photosynthesis may be the cause of leaf senescence and short-lived. Short-lived and fast-aging leaf stalks in different seasons can distribute the energy substance to the top of the stolons and promote the growth of young leaves and stolons at the top of the stolons and their spread, which is important in maintaining the viability of white clover plants The regulatory role.