Din Najam-Ud-, Ye Weiguo, Chen Jianjun, Deng Shiyuan, Zhong Xianyun, Chen Yanbing
College of Agriculture, South China Agricultural University, Guangzhou, China.
Front Plant Sci. 2025 Sep 8;16:1638344. doi: 10.3389/fpls.2025.1638344. eCollection 2025.
Extreme low-temperature (LT) events, exacerbated by climate change, are increasingly threatening China's tobacco harvest. This study examines the impact of LT stress on growth biomarkers, antioxidant enzyme activities, and physiological parameters in two tobacco varieties, K326 and Huayan06. Under LT conditions, Huayan06 showed reduced stomatal conductance under LT conditions and a significantly lower PN than K326. Both varieties exhibited an initial increase followed by a decrease in intercellular CO concentration and chlorophyll fluorescence parameters (Fv/Fm and ΦPSII). Notably, PSII efficiency and photochemical quenching declined sharply when temperatures dropped below 12°C and 16°C. The maximal photochemical efficiency and PN decreased within the first 6-12 hours. K326 leaves displayed higher conductivity and malondialdehyde (MDA) content than Huayan06, indicating more significant LT-induced damage. The ascorbic acid (ASA) and dehydroascorbic acid (DHA) contents varied between the varieties, with Huayan06 showing more resilience. Huayan06 also exhibited a stable glutathione (GSH) content and higher antioxidant enzyme activities superoxide dismutase (SOD), monodehydroascorbate reductase (MDAR), dehydro-ascorbate reductase (DHAR) and ASA during the initial hours of LT exposure, though these declined later. In contrast, K326 showed a substantial rise in DHA and lower GSH levels over time. RuBPase and FDPase activities were significantly reduced under LT treatment. Huayan06 experienced a 44.2% reduction in dry matter accumulation, compared to a 66.4% reduction in K326, demonstrating Huayan06's superior capacity for dry matter production and resistance to LT stress.
极端低温（LT）事件因气候变化而加剧，正日益威胁着中国的烟草收成。本研究考察了低温胁迫对两个烟草品种K326和华烟06生长生物标志物、抗氧化酶活性及生理参数的影响。在低温条件下，华烟06的气孔导度降低，净光合速率（PN）显著低于K326。两个品种的细胞间CO浓度和叶绿素荧光参数（Fv/Fm和ΦPSII）均先升高后降低。值得注意的是，当温度降至12°C和16°C以下时，PSII效率和光化学猝灭急剧下降。最大光化学效率和净光合速率在最初的6 - 12小时内下降。K326叶片的电导率和丙二醛（MDA）含量高于华烟06，表明低温诱导的损伤更显著。两个品种的抗坏血酸（ASA）和脱氢抗坏血酸（DHA）含量有所不同，华烟06表现出更强的恢复能力。华烟06在低温暴露的最初几个小时内还表现出谷胱甘肽（GSH）含量稳定，超氧化物歧化酶（SOD）、单脱氢抗坏血酸还原酶（MDAR）、脱氢抗坏血酸还原酶（DHAR）和ASA等抗氧化酶活性较高，不过这些指标后来有所下降。相比之下，K326的DHA含量大幅上升，GSH水平随时间降低。低温处理下核酮糖-1,5-二磷酸羧化酶（RuBPase）和果糖-1,6-二磷酸酶（FDPase）活性显著降低。华烟06的干物质积累减少了44.2%，而K326减少了66.4%，这表明华烟06具有更强的干物质生产能力和抗低温胁迫能力。
