低温驯化对菊花品种抗寒性的影响

【目的】明确低温驯化的对于菊花耐冷性的积极作用，以期为菊花耐低温的深入研究和菊花抗寒品质的进一步挖掘提供理论参考。【方法】以姹紫嫣红和金龙腾云2个菊花品种为试验材料，分别设低温处理（-4℃下24 h）和低温驯化（先4℃下24 h即低温驯化过程，然后-4℃处理24 h），以常温（25℃）为对照，测定并分析叶片中叶绿素含量、抗氧化酶活性、相对电导率（REC）、丙二醛（MDA）、脯氨酸（Pro）及活性氧等生理指标变化，分析各生理指标的相关性，并运用隶属函数法进行2个菊花品种的耐低冷性综合评价。【结果】低温驯化和低温处理后，2个菊花品种叶片的叶绿素含量和抗氧化酶活性均表现出逐渐降低的趋势；而叶片的REC及MDA和Pro含量则表现出逐渐上升的趋势。经过低温驯化的2个品种叶片中的过氧化物酶（POD）活性、REC及MDA、Pro、过氧化氢（H₂O₂）和超氧阴离子（O-₂）含量均显著低于低温处理（P<0.05，下同）。其中，金龙腾云品种在POD活性、REC及Pro和O-₂含量表现明显，MDA和H₂O₂含量则在姹紫嫣红品种上表现明显；叶绿素含量和POD活性则显著高于低温处理；在金龙腾云品种上叶绿素a、叶绿素b含量及POD活性分别比低温处理提高38%、54%和18%，类胡萝卜素含量在姹紫嫣红品种中比低温处理增长一倍。相关分析显示，金龙腾云的耐冷性大于姹紫嫣红。在未经低温驯化条件下，金龙腾云的耐冷性表现优于低温驯化；而姹紫嫣红的耐冷性表现劣于低温驯化。【结论】低温驯化后，2个菊花品种生理特性均优于低温处理，金龙腾云比姹紫嫣红更耐冷，低温驯化对菊花叶片的机械损伤能起到一定的保护作用，降低了菊花细胞质膜受伤害的程度，进而提高菊花对低温的抵御能力。

Effects of cold acclimation on cold resistance of chrysanthemum varieties

【Objective】 To clarify the positive effects of cold acclimation on chrysanthemum cold resistance, so as to provide a theoretical reference for further research on chrysanthemum cold resistance and further exploration of chrysanthemum cold resistance quality.【Method】 Two chrysanthemum varieties, Chazi Yanhong and Jinlong Tengyun, were used as test materials. Cold treatment(24 h at -4℃) and cold acclimation treatment(cold acclimation for 24 h at 4℃ and then 24 h at -4℃) were set and normal temperature(25℃) was taken as the control to determine the changes of physiological indexes such as chlorophyll content, antioxidant enzyme activity, relative conductivity(REC), malondialdehyde(MDA), proline(Pro), active oxygen and to analyze the correlation of various physiological indexes. Membership function method was used to comprehensively evaluate cold tolerance of the two chrysanthemum varieties.【Result】 After cold acclimation and cold treatment, the chlorophyll content and antioxidant enzyme activity of chrysanthemum leaves of the two chrysanthemum varieties decreased gradually, but REC, MDA and Pro content of the leaves gradually increased. Peroxidase (POD) activity, REC, content of MDA, Pro, hydrogen peroxide (H₂O₂) and superoxide anion (O₂-) in the leaves of the two varieties in the cold acclimation treatment group were significantly lower than those in the cold treatment group(P<0.05, the same below). POD activity, REC, Pro and O₂- content changed significantly in Jinlong Tengyun variety, while MDA and H₂O₂ content in the Chazi Yanhong variety significantly decreased. Chlorophyll content and POD activity in cold acclimation treatment group were significantly higher than those in cold treatment group. Content of chlorophyll a, chlorophyll b and POD activity of Jinlong Tengyun variety increased by 38%, 54% and 18% respectively compared with those in cold treatment group. Carotenoid content doubled in the Chazi Yanhong variety compared with that in cold treatment group. The correlation ana-lysis showed that the cold tolerance of Jinlong Tengyun was greater than that of Chazi Yanhong. Without cold acclimation, the cold tolerance of Jinlong Tengyun was better than that under cold acclimation, while the cold tolerance of Chazi Yanhong was worse than that under cold acclimation.【Conclusion】 After cold acclimation, the physiological characteristics of the two varieties are better than those before cold acclimation, and Jinlong Tengyun has better cold tolerance than Chazi Yanhong, which indicates that cold acclimation could protect chrysanthemum to a certain extent, reduce the degree of damage caused to the plasma membrane of chrysanthemum cells, thus improving cold resistance of chrysanthemum.