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以河南烟区主栽烟草(Nicotiana tabacum)品种‘豫烟10号’和‘豫烟12号’为供试材料,利用聚乙二醇(PEG)-6000渗透胁迫模拟轻度、中度和重度干旱胁迫环境,研究了烟草抗旱性生理指标对苗期不同程度水分亏缺的响应机制及其与烟株耐旱性的关系。结果表明:(1)相比于对照组,低浓度PEG胁迫能促进烟草幼苗叶片叶绿素(Chl)含量和抗氧化酶活性提高;叶片丙二醛(MDA)和过氧化氢(H_2O_2)含量随着干旱程度的加剧持续升高;重度水分胁迫时,幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)等保护酶活性以及Chl含量均显著下降。(2)应用隶属函数法对各项抗旱性生理指标进行综合评价,2个烟草品种苗期抗旱性强弱顺序为‘豫烟12号’>‘豫烟10号’,总体趋势表现为水分条件越差二者抗旱性差异越明显,‘豫烟12号’幼苗的各生理生化指标较‘豫烟10号’受干旱影响小,干旱胁迫下仍保持较强的抗氧化酶活性是‘豫烟12号’耐旱的主要生理原因,这是不同品种通过自身生理调节来适应外部环境变化的结果。(3)灰色关联分析表明,各参数与抗旱隶属函数值关联程度顺序依次为MDA>SOD>(Chl a/Chl b)>H_2O_2>CAT>POD>(Chl a+b),说明叶片内MDA含量、SOD活性和Chl a/Chl b可作为烟草品种苗期抗旱性鉴定的有效指标,而H_2O_2含量、CAT活性、POD活性和Chl a+b参数可作为抗旱性鉴定参考指标。
The Nicotiana tabacum varieties ’Yuyan 10’ and ’Yuyan 12’ were used as materials to simulate the mild, moderate and severe effects of osmotic stress with polyethylene glycol (PEG) -6000 Drought stress environment. The response mechanism of drought resistance physiological indexes to different degrees of water deficit at seedling stage and their relationship with drought tolerance of tobacco plants were studied. The results showed that: (1) Compared with the control, low concentration of PEG could promote the increase of chlorophyll (Chl) content and antioxidant enzyme activity in leaves of tobacco seedlings. The content of malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2) The severity of drought increased continuously. Under heavy water stress, the activity of protective enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and the content of Chl in seedling leaves decreased significantly. (2) The membership function method was used to comprehensively evaluate physiological indexes of drought resistance. The order of drought resistance at the seedling stage of two tobacco cultivars was Yu’anyu12> Yu’Yusu10. The general trend was water condition The worse the drought resistance difference between the two was, the more the physiological and biochemical indexes of’Yanyan12’were less affected by drought than ’Yuyan10’and the stronger antioxidant enzyme activity was still’ Yuyu 12 ’main physiological causes of drought, which is different varieties through their own physiological adjustment to adapt to changes in the external environment results. (3) Gray relational analysis showed that the order of the correlation between each parameter and drought resistance membership function was in order of MDA> SOD> Chl a / Chl b> H 2 O 2> CAT> POD> (Chl a + b) , SOD activity and Chl a / Chl b could be used as effective indicators to identify the drought resistance of tobacco varieties at seedling stage, while H 2 O 2 content, CAT activity, POD activity and Chl a + b parameters could be used as reference indicators for drought resistance identification.