Collaborative Innovation Center of Henan Grain Crops, Henan Key Laboratory of Rice Biology, Henan Agricultural University, Zhengzhou, China.
Department of Agronomy, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, 1207, Bangladesh.
Protoplasma. 2019 Sep;256(5):1217-1227. doi: 10.1007/s00709-019-01354-6. Epub 2019 Apr 18.
Seed germination is one of the most important biological processes in the life cycle of plants, and temperature and water are the two most critical environmental factors that influence seed germination. In the present study, we investigated the roles of the plant hormone abscisic acid (ABA) and reactive oxygen species (ROS) in high temperature (HT) and drought-induced inhibition of rice seed germination. HT and drought stress caused ABA accumulation in seeds and inhibited seed germination and seedling establishment. Quantitative real-time polymerase chain reaction analysis revealed that HT and drought stress induced the expression of OsNCED3, a key gene in ABA synthesis in rice seeds. In addition, ROS (O and HO) and malondialdehyde contents were increased in germinating seeds under HT and drought stress. Moreover, we adopted the non-invasive micro-test technique to detect HO and Ca fluxes at the site of coleoptile emergence. HT and drought stress resulted in a HO efflux, but only drought stress significantly induced Ca influx. Antioxidant enzyme assays revealed that superoxide dismutase (SOD), peroxidase, catalase (CAT), and ascorbate peroxidase (APX) activity were reduced by HT and drought stress, consistent with the expression of OsCu/ZnSOD, OsCATc, and OsAPX2 during seed germination. Altogether, these results suggest that ABA and ROS accumulation under HT and drought conditions can inhibit rice seed germination and growth.
种子萌发是植物生命周期中最重要的生物学过程之一，而温度和水是影响种子萌发的两个最关键的环境因素。在本研究中，我们研究了植物激素脱落酸（ABA）和活性氧（ROS）在高温（HT）和干旱诱导的水稻种子萌发抑制中的作用。HT 和干旱胁迫导致种子中 ABA 的积累，从而抑制种子的萌发和幼苗的建立。定量实时聚合酶链反应分析显示，HT 和干旱胁迫诱导了水稻种子中 ABA 合成的关键基因 OsNCED3 的表达。此外，ROS（O 和 HO）和丙二醛含量在 HT 和干旱胁迫下萌发的种子中增加。此外，我们采用非侵入性微测试技术在 coleoptile 萌发部位检测 HO 和 Ca 通量。HT 和干旱胁迫导致 HO 流出，但只有干旱胁迫显著诱导 Ca 流入。抗氧化酶测定显示，超氧化物歧化酶（SOD）、过氧化物酶、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）的活性在 HT 和干旱胁迫下降低，与种子萌发过程中 OsCu/ZnSOD、OsCATc 和 OsAPX2 的表达一致。总之，这些结果表明，ABA 和 ROS 在高温和干旱条件下的积累可以抑制水稻种子的萌发和生长。
