金花茶对低温胁迫的生理响应及耐寒性分析

为探究金花茶幼苗对低温胁迫的生理响应及其耐寒性,本研究以2 a生金花茶幼苗为材料,进行6~-9℃低温胁迫处理,测定了细胞伤害率(CIR)、丙二醛(MDA)、过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、束缚水(BW)/自由水(FW)、脯氨酸(Pro)、可溶性糖(SS)等指标,并进行了低温半致死温度(LT₅₀)和抗寒生理指标相关性分析。结果表明,3~12 h的低温LT₅₀为-6.62~-3.94℃,且随着时间的延长而升高。随着温度的降低, CIR、SS含量及POD、CAT活性总体呈上升趋势, BW/FW、MDA、Pro含量呈先上升后下降趋势, SOD活性总体呈下降趋势;随着胁迫时间的延长,CIR含量呈上升趋势,3~-9℃的SOD活性、0~-9℃的POD活性、-6~-9℃的BW/FW比值呈下降趋势,6~-6℃的SS含量变化较小,-9℃的SS含量呈下降趋势。相关性分析表明,CIR可作为耐寒性鉴定的主要指标,BW、SS、SOD、POD、CAT可作为辅助指标。本研究结果为金花茶引种区域和耐寒性鉴定指标的确定提供了理论依据。

Physiological Responses and Cold Resistance Analysis of Camellia nitidissima Chi Under Low-temperature Stress

To study the physiological response and the cold tolerance of Camellia nitidissima Chi seedlings, two-year-old C. nitidissima seedlings were treated with low temperature stress at 6~-9℃.The indicators of cell injury rate(CIR), malondialdehyde (MDA) , peroxidase (POD), catalase (CAT) , superoxide dismutase (SOD), bound water (BW)/free water (FW), proline (Pro), and soluble sugar (SS) were determined, and the semi-lethal temperature (LT50) and the correlation between physiological indicators were analyzed. The results suggested that, the low-temperature LT50 of 3~12 h was -6.62~-3.94℃ and increased with time going. With the decrease of temperature, the CIR, SS, the activities of POD and CAT showed an overall upward trend, while the value of the BW /FW, the content of MDA and Pro increased first and then decreased. Moreover, the activity of SOD declined in general. As the stress time extended, CIR would rise significantly, while the activity of SOD at 3~-9℃, the activity of POD at 3~-9℃ and the BW/FW value at -6~-9℃ declined, as well as the SS content at 6~-6℃ changed slightly, which showed a downward trend at -9℃. Correlation analyses demonstrated that CIR could be used as a main indicator, while BW, SS, SOD, POD and CAT could be used as the auxiliary indicators for cold resistance identification. In summary, the results of this study provide a theoretical basis for the determination of the introduction area and cold resistance index of C. nitidissima.