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南方型黑杨生长和生理特性对持续干旱和复水响应的性别差异

段启英,田野*,鄂晓伟,秦广震,张贾宇   

  1. (南京林业大学林学院, 南京林业大学南方现代林业协同创新中心, 南京 210037)
  • 出版日期:2020-07-10 发布日期:2021-01-09

Sexual differences in growth and physiological properties of southern-type poplar clones in response to continuous drought and re-watering.

DUAN Qi-ying, TIAN Ye*, E Xiao-wei, QIN Guang-zhen, ZHANG Jia-yu   

  1. (College of Forestry/CoInnovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China).
  • Online:2020-07-10 Published:2021-01-09

摘要: 干旱是限制南方型黑杨分布和生长的关键环境因子,而不同性别的黑杨无性系对干旱胁迫可能具有不同的耐受性和相应的生理响应。本研究以南方型黑杨雌性无性系南林895杨(Populus × euramericana ‘Nanlin895’)和雄性无性系南林3804杨(P. deltoides ‘Nanlin3804’)1年生扦插苗为试验材料,通过盆栽方式进行持续干旱和干旱复水处理,从生长和生理响应方面比较雌、雄无性系对干旱胁迫的耐受和恢复能力,并对其抗旱能力产生差异的生理机理进行探讨。结果表明:持续性的干旱明显抑制南方型黑杨雌、雄无性系1年生扦插苗的生长,叶片细胞和组织膜脂过氧化,导致膜系统受到破坏,同时叶片丙二醛(MDA)含量、抗氧化酶(SOD和POD)活性以及游离脯氨酸含量均升高,直至植株死亡;重度干旱后植株叶片快速失水,叶绿素出现“浓缩”现象;与雌性无性系相比,雄性无性系在持续干旱下地上部分生物量较小,但更大程度地增加根系的生物量,从而增强植株吸水能力,并降低蒸腾耗水;同时能更早以及更大幅度地提高叶片的抗氧化酶活性,且更长时间维持较高的酶活性,从而降低和缓解干旱胁迫所产生的膜脂过氧化,维持细胞和组织的正常生理功能,延缓植株的死亡;复水后,雄性无性系能更快速地恢复至正常生理状态,从而维持一定的生长量。总体而言,南方型黑杨雄性无性系比雌性无性系具有相对较强的耐旱能力,可以优先选择用于山地造林。

关键词: 耕作方式, 干物质积累与分配, 籽粒产量, 光合特性, 水分利用效率

Abstract: Drought is an important environmental factor restraining the distribution and growth of southern-type poplar clones. Sex-specific poplar clones may have different tolerance and corresponding physiological responses to drought stress. In this study, we compared the sex-specific response to continuous drought stress and rewatering in a pot experiment using one-year-old cuttings of male (Populus deltoides ‘Nanlin 3804’) and female (P. × euramericana ‘Nanlin895’) southerntype poplar clones. The results showed that continuous drought significantly restrained the growth of both female and male poplar clones. Under continuous drought stress, membrane lipids of leaf cells and tissues sustained peroxidation, which led to the destruction of membrane system. Furthermore, leaf MDA content, antioxidant enzyme (SOD and POD) activity, and free proline content increased significantly under continuous drought before plant death. Under severe drought, the leaves of both clones lost water quickly, with a “concentrated” phenomenon of chlorophyll. Compared to female clone, the above-ground biomass of male clone was lower, while root biomass increased under continuous drought, thereby enhancing its water absorption capacity and reducing transpiration and water loss. Meanwhile, male clone increased the antioxidant enzyme activities in leaves earlier and more greatly, and kept for much longer period, than female clone. Such differences alleviated the peroxidation of membrane lipid, maintained normal physiological functions of cells and tissues, and delayed plant death. After re-watering, the male clone recovered to normal physiological state more quickly, which ensured its higher growth than female clone. In general, male clone of southern-type poplar showed relatively stronger drought tolerance than female clone, thus it could be used for afforestation in mountainous areas.

Key words: photosynthetic characteristics, dry matter accumulation and allocation, water use efficiency., tillage practices, grain yield