《植物生理学报》 2016, 52(12): 1861-1871

两种烟草幼苗叶片对不同强度干旱胁迫的生理响应比较

邵惠芳¹, 陈征¹, 许嘉阳², 范艺宽³, 黄五星¹, 张海枞¹, 许自成^1,*

¹河南农业大学烟草学院, 郑州450002; ²中国农业大学农学与生物技术学院, 北京100193; ³河南省烟草公司烟草研究所, 郑州472000

通信作者：许自成；E-mail: zichengxu@126.com

摘　要：

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(H₂O₂)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)> H₂O₂>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H₂O₂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。

关键词：烟草; 干旱胁迫; 生理响应; 抗旱性; 评价

收稿：2016-06-12   修定：2016-11-02

资助：国家自然科学基金(31200393)和河南省烟草公司科技攻关项目(HYKJ 201210和HYKJ 201405)。

Physiological responses of two tobacco cultivar leaves to different drought stresses during seedling stage

SHAO Hui-Fang¹, CHEN Zheng¹, XU Jia-Yang², FAN Yi-Kuan³, HUANG Wu-Xing¹, ZHANG Hai-Cong¹, XU Zi-Cheng^1,∗

¹College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China; ²Agronomy and Biotechnology College, China Agricultural University, Beijing 100193, China; ³Tobacco Research Institute of Henan Provincial Tobacco Company, Zhengzhou 472000, China

Corresponding author: XU Zi-Cheng; E-mail: zichengxu@126.com

Abstract:

Drought is one of the numerous environmental factors which seriously affects the growth and development of plants, and it is becoming more severe in many regions of the world due to climate change. To examine physiological responses of tobacco seedling to polyethylene glycol (PEG) stress and provide theoretical basis for evaluating drought resistance and screening tobacco species, the physiological and biochemical indexes of two tobacco cultivars were investigated under the conditions of light drought (LD), intermediate drought (ID) and severe drought (SD). The results show that malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) contents were significantly increased than those of the control, while activities of protective enzymes and chlorophyll contents were obviously increased and then significantly decreased under the ID or SD treatments. The enzyme activities in ‘Yuyan 10’ increased more strongly than those in ‘Yuyan 12’. Meanwhile, MDA content in ‘Yuyan 10’ changed more obviously than that in ‘Yuyan 12’, which may be related to the enhanced enzyme activity during droughts, more exactly, a strong negative correlativity between MDA content and enzyme activities was shown under water stress. Subordinate function of drought-resistance and its correlation with drought-resistance indexes of tobacco species were used for a quantitative evaluation of comprehensive drought-resistance. The capabilities of drought-resistance for two different tobacco species were in the order ‘Yuyan 12’>‘Yuyan 10’. There was a significant tendency that drought-resistant varieties were more easily adapted to water stress environment than drought-susceptible varieties, and the slight variations of index only occurred in the drought-resistant varieties. The grey correlative degree of drought-resistance with other physiological indexes was in the rank of MDA content, SOD activity, H₂O₂ content, Chl a/Chl b, POD activity, CAT activity and Chl a+b content. Therefore, the SOD activity, MDA content and Chl a/Chl b can be used as effective indicators for the identification of drought resistance, while H₂O₂ content, CAT activity, POD activity and Chl a+b content can be used for reference indicators at seedling stage for tobacco species.

Key words: tobacco; drought stress; physiological response; drought resistance; evaluation