《植物生理学报》 2018, 54(3): 473-482

淹水胁迫下北美鹅掌楸无性系生理生化响应差异

孙小艳¹, 陈铭², 李彦强¹, 吴照祥¹, 钟永达¹, 余发新^1,*

¹江西省科学院生物资源研究所, 南昌330096; ²南昌大学江西医学院, 南昌330006

通信作者：余发新；E-mail: yufaxin@jxas.ac.cn

摘　要：

北美鹅掌楸(Liriodendron tulipifera)是优良用材和绿化树种, 但极不耐涝, 阻碍了其广泛应用。本研究以前期试验筛选出的3个耐淹无性系(T4、T27和T37)和3个不耐淹无性系(S5、S9和S20)为实验材料, 开展温室盆栽模拟淹水胁迫实验, 通过比较丙二醛(MDA)含量、相对电导率(EL)、叶绿素含量, 以及酶活性等生理生化指标的差异, 探索不同无性系对淹水胁迫的响应和抗性差异。结果显示: 北美鹅掌楸对淹水胁迫反应敏感, 淹水4 d时, 耐淹无性系和敏感无性系均呈现下部老叶黄花, 上部嫩叶、顶芽萎蔫现象, 叶绿素含量减少, MDA、EL显著增加, 超氧化物歧化酶(SOD)和过氧化物酶(POD)等酶活性极显著增加。淹水6 d后, 敏感无性系受到的胁迫伤害进一步加剧, 叶片萎蔫脱落, MDA、EL持续增加, 叶绿素含量极显著降低, SOD和POD总体呈下降趋势; 而耐淹无性系顶芽缓慢恢复, 在叶片脱落后幼叶展开, 叶绿素含量下降幅度较小, MDA和EL缓慢下降, SOD和POD持续升高, 淹水20 d左右近水面的茎端形成不定根和大量膨大皮孔。研究表明: 耐淹型北美鹅掌楸可通过形成不定根和肥大的皮孔、保持较高的抗氧化酶活性等方式增强其抗涝能力; EL、叶绿素含量、SOD活性可作为北美鹅掌楸耐淹无性系中期选育指标。

关键词：北美鹅掌楸; 淹水胁迫; 生理响应差异; 抗氧化酶活性

收稿：2017-08-14   修定：2018-01-15

资助：江西省学术带头人培养计划项目(20133BCB22012)、江西省优势科技创新团队计划项目(20161BCB24008)、江西省科技支撑计划项目(20123BBF60179和20132BBF60032)和江西省科学院普惠项目(2013-XTPH2-8)。

Variations in physiological and biochemical responses in clones of Liriodendron tulipifera under flooding stress

Sun Xiao-Yan¹, Chen Ming², Li Yan-Qiang¹, Wu Zhao-Xiang¹, Zhong Yong-Da¹, Yu Fa-Xin^1,*

¹Institute of Biology and Resources, Jiangxi Academy of Sciences, Nanchang 330096, China; ²Jiangxi Medical School, Nanchang University, Nanchang 330006, China

Corresponding author: Yu Fa-Xin; E-mail: yufaxin@jxas.ac.cn

Abstract:

Yellow poplar (Liriodendron tulipifera) is a good timber and landscape tree species. However, its widespread planting is hindered because it is sensitive to flooding. Three tolerant clones (T4, T27 and T37) and three sensitive clones (S5, S9 and S20) were selected and a potted experiment of flooding stress in greenhouse was conducted. Physiological and biochemical properties, including malondialdehyde (MDA) content, electrolyte leakage (EL), chlorophyll content and enzyme activities were applied to explore the different flooding responses in yellow polar clones and tolerant mechanism under flooding stress. The results show that flooding stress seriously inhibited the growth of yellow poplar. All experimental seedlings presented damaged phenotype (old leaf yellowing, apical bud and young leaf wilting), meanwhile chlorophyll content decreased, MDA content and EL increased significantly, and SOD and POD activities motivated at flooding for 4 d. After 6 d, the sensitive clones were furtherly damaged with MDA content and EL dramatically increasing, while SOD and POD activities decreasing. On the contrast, the tolerant clones began to grow new leaves after yellow leaves falling off. Meanwhile, the MDA content and EL decreased, the decreasing of chlorophyll content was inhibited, and SOD and POD activities constantly increased. Moreover, the tolerant clones formatted adventitious roots and massive stem hypertrophic lenticels around 20 d. The results indicate that formation of adventitious roots and hypertrophic lenticels, and maintenance of antioxidant activity could contribute to better flooding tolerance of yellow poplar. EL, chlorophyll content, and SOD activity would be used as rapid and simple indexes for selecting flooding-tolerant genotypes.

Key words: Liriodendron tulipifera; flooding stress; variation of physiological response; antioxidant enzyme activity