Zhang Sheng-Nan, Huang Yi-Zong, Li Yan, Bao Qiong-Li, Huang Yong-Chun
Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China.
Huan Jing Ke Xue. 2021 Apr 8;42(4):2040-2046. doi: 10.13227/j.hjkx.202007290.
In order to explore the effects of the exogenous addition of plant hormones on the antioxidant system and Cd absorption and accumulation of rice seedlings under Cd stress, the transportation and accumulation of Cd was reduced in plants to alleviate the stress of Cd on the rice. With the rice seedlings of Zhongjiazao 17 as the research object, a hydroponic experiment was carried out with three Cd concentration treatments (0, 5, and 25 μmol·L), and four exogenous plant hormone treatments:no plant hormones, 100 μmol·L melatonin (MT), 0.2 μmol·L 2,4-epibrassinolide (EBL), and 0.2 μmol·L jasmonic acid (JA), for a total of 12 treatments, each treatment repeated three times. The contents of Cd in the rice seedlings were analyzed, as well as the content of MDA, POD, CAT, and reduced GSH in the shoots and roots of the rice seedlings. The results indicated that under the stress of 5 μmol·L and 25 μmol·L Cd, the addition of MT, EBL, and JA significantly reduced the MDA content of the shoots by 11%-24%, and the roots and shoots were healthy. On the contrary, the addition of the three exogenous substances all caused an increase in the MDA content in the root system, but the effects of MT and EBL were obvious. Under the 5 μmol·L Cd stress, compared with CK, the MDA contents increased by 45.5% and 20.0% respectively; under 25 μmol·L Cd stress, they increased by 46.2% and 19.8%. The exogenous addition of plant hormones can significantly increase the activity of POD and CAT in the shoots and underground parts of the rice seedlings and reduce the contents of GSH and Cd. Under the 5 μmol·L Cd stress, the Cd content in the shoots of rice plants decreased by 39.4%, 40.1%, and 51.6%, the roots were reduced by 38.9%, 40.2%, and 7.0%. Under the 25 μmol·L Cd stress, the aboveground Cd content was reduced by 18.9%, 14.5%, and 35.6%, and the roots were reduced by 85.3%, 81.1%, and 56.5%. By exogenously adding low-concentration plant hormones MT, EBL, and JA, the stress of Cd on the rice can be alleviated, and the toxic effect of Cd on rice can be reduced.
为探究外源添加植物激素对镉胁迫下水稻幼苗抗氧化系统及镉吸收积累的影响，降低植物体内镉的运输和积累，以减轻镉对水稻的胁迫。以中嘉早17水稻幼苗为研究对象，进行水培试验，设置3种镉浓度处理（0、5和25 μmol·L），以及4种外源植物激素处理：不添加植物激素、100 μmol·L褪黑素（MT）、0.2 μmol·L 2,4-表油菜素内酯（EBL）和0.2 μmol·L茉莉酸（JA），共12个处理，每个处理重复3次。分析了水稻幼苗中镉的含量，以及水稻幼苗地上部和根部丙二醛（MDA）、过氧化物酶（POD）、过氧化氢酶（CAT）和还原型谷胱甘肽（GSH）的含量。结果表明，在5 μmol·L和25 μmol·L镉胁迫下，添加MT、EBL和JA显著降低了地上部MDA含量11%-24%，地上部和根部生长健康。相反，添加这3种外源物质均导致根系MDA含量增加，但MT和EBL的影响明显。在5 μmol·L镉胁迫下，与对照相比，MDA含量分别增加了45.5%和20.0%；在25 μmol·L镉胁迫下，分别增加了46.2%和19.8%。外源添加植物激素能显著提高水稻幼苗地上部和地下部POD和CAT的活性，降低GSH和镉的含量。在5 μmol·L镉胁迫下，水稻地上部镉含量分别降低了39.4%、40.1%和51.6%，根部降低了38.9%、40.2%和7.0%。在25 μmol·L镉胁迫下，地上部镉含量分别降低了18.9%、14.5%和35.6%，根部降低了85.3%、81.1%和56.5%。通过外源添加低浓度植物激素MT、EBL和JA，可减轻镉对水稻的胁迫，降低镉对水稻的毒害作用。
