ABSTRACT

Hydroxyl radical (•OH) is considered to be the most damaging among reactive oxygen species. Although afew studies have reported on its effects on growth and stress adaptation of plants, no detailed studies have been performed using •OH in germination and early seedling growth under abiotic stresses. Here we report a single seed treatment with •OH on germination and seedling growth of Arabidopsis and rice under non-stressed (ambient) and various abiotic-stressed conditions (chilling, high temperature, heat, and salinity). The treatment resulted in faster seed germination and early seedling growth under non-stressed conditions, and, interestingly, these effects were more prominent under abiotic stresses. In addition, Arabidopsis seedlings from treated seeds showed faster root growth and developed more lateral roots. These results show apositive and potential practical use for •OH in model and crop plants for direct seeding in the field, as well as improvement of tolerance against emerging stresses.

Abbreviations: AUC: area under curve; MGT: mean germination time; t50: time to reach 50% germination; U₇₅₂₅: time for uniform germination from 25% to 75%; ROS: reactive oxygen species; GSI: germination speed index; SI: stress index; DI: dormancy index

摘要

羟自由基（•OH）被认为是活性氧中最具破坏性的物质。尽管很少有研究报道其对植物生长和逆境适应的影响，但是在非生物胁迫下，使用•OH进行发芽和幼苗早期生长的详细研究尚未进行。在这里，我们报告了在无胁迫（环境）和各种非生物胁迫（寒冷，高温，高温和盐碱化）的条件下，用•OH处理拟南芥和水稻的发芽和幼苗生长的单种种子处理。在非胁迫条件下，该处理可导致更快的种子发芽和幼苗早期生长，有趣的是，这些作用在非生物胁迫下更为突出。此外，拟南芥处理过的种子的幼苗显示出较快的根系生长，并发育出更多的侧根。这些结果显示了•OH在模型和农作物中用于田间直接播种的积极和潜在的实际应用，以及对新出现的胁迫的耐受性的提高。

缩写： AUC：曲线下面积；MGT：平均发芽时间；t50：达到50％发芽的时间；U ₇₅₂₅：均匀发芽时间从25％到75％；ROS：活性氧；GSI：发芽速度指数；SI：应力指数；DI：休眠指数