澳洲茶树对淹水胁迫的生长和生理响应

Growth and Physiological Response of Melaleuca alternifolia to Flooding Stress

以1年生澳洲茶树(Melaleuca alternifolia)组培苗为研究对象,采用双套盆法进行盆栽淹水试验,研究淹水胁迫对澳洲茶树生长和生理特性的影响,为其推广种植提供理论依据。结果表明,淹水60 d内叶片不萎蔫,苗木成活率为100%,但苗木生长速度受到一定程度的抑制;过氧化物酶(POD)活性随淹水时间的增加逐渐提高,为淹水胁迫的主要响应酶;超氧化物歧化酶(SOD)活性前10 d波动升高,之后整体呈波动下降的趋势;过氧化氢酶(CAT)活性前16 d较高;硝酸还原酶(NR)活性18~30 d时较高;谷胱甘肽过氧化物酶(GSH-PX)活性呈先升高后下降的趋势,前38 d活性较高;丙二醛(MDA)含量呈连续M型变化后降为胁迫前的水平;脯氨酸含量在16 d时急剧上升;可溶性糖含量呈先增加后降低的趋势。澳洲茶树具有较强的耐涝性,可通过提高保护酶活性和调节代谢逐渐适应淹水环境,但生长速度较慢,为保证其生长速度,在淹水时应及时排水。

Taking 1-year-old tissue culture seedlings of Melaleuca alternifolia as materials, experiment of water flooding was carried out by using double-set pot method to study influences of flooding stress on growth and physiological characteristics of M. alternifolia, which could provide theoretical basis for popularization of M. alternifolia. Results showed that within 60 d of flooding, leaves were not wilted, and survival rate of seedlings was100%. But growth speed of seedlings was inhibited to some extent. POD activity gradually increased with increase of flooding time, which was the main response enzyme to flooding stress. SOD activity increased in early10 d, and then showed a trend of fluctuation and decline. CAT activity was higher before 16 d. NR activity was higher in 18-30 d. GSH-PX activity increased firstly and then decreased, with higher activity before 38 d.MDA content showed continuous M-type changes and then decreased to level before stress. Proline content increased sharply at 16 d. Soluble sugar content increased firstly and then decreased. M. alternifolia had strong flooding resistance, which could gradually adapt to flooding environment by improving activities of protective enzymes and regulating metabolism, but growth speed was slow. In order to ensure growth speed, drainage in time should be done when M. alternifolia grew in flooding environment.