Identifying plant survival strategies during and after floods: Traits related to successful field seedling establishment during water excess and drawdown periods

F.P.O. MOLLARD,

Buenos Aires

Jornada; Humboldt Colloquium; 2018

Alexander von Humboldt Foundation

There is a noticeable increase in the severity of flooding events damaging crops and pastures in farmlands. I pursue two poorly studied research lines related to plant performance under flooded conditions and post flooding periods. On the one hand, hydrophyte weeds thrive and persist as seeds in the soil seed bank of low lying farmlands and rice fields. Currently we do not count with a conceptual framework able to predict seed responses to flooding even for hydrophyte species. Then, one of my research objectives is to study seed dormancy as a strategy to avoid precocious germination and emergence failure during floods. This research line studies the seed dormancy and germination behaviour of several hydrophyte weeds (such as red rice and barnyard grass) under environmental conditions that simulate those found in flooded soil seed banks and under treatments known to alleviate or break seed dormancy. This study will make it possible to model the behaviour of hydrophyte seeds in the seed bank and incorporate the risk of flooding into weed emergence field models. The high interest of this research lies on clarifying the functional link between floods and seed dormancy in wetland weeds and explore, for the first time, the ability of submerged seeds to perceive dormancy breaking cues. On the other hand, I study the development of root systems during waterlogging and hypoxia and its recovery during the drawdown period. Most crop plants lose their root systems during waterlogging and continue with this trend even when floodwaters have receded. The first aim of this project is to identify regulatory processes and genes related to the determination of root architecture that help seedlings to withstand floods and can be manipulated to breed flood tolerant crops. To attain this aim I study the role of molecular oxygen and that of the main hormones affecting root growth and development by means of phenotypic characterization of mutant and transgenic Arabidopsis and Lotus japonicus genotypes and the expression of main hypoxia related genes.