How Do Plants Deal with Flood and Drought? Biotechnological Strategies to Enhance the Natural Response and Improve Yield

RIBICHICH KF; CHAN RL

ISB News Reports-Agricultural and Environmental Biotechnology

Virginia Libraries

Lugar: Virginia; Año: 2015

Water deficitand water excess are major factors affecting plants yield worldwide. To copewith such factors, plants trigger physiological and biochemical changesallowing them to survive for a limited period of time. Plants dealwith water deficit thanks to some oftheir morphological and physiological characteristics and their ability tomodify some of them. Examples of these characteristics are the cuticle thatreduces transpiration, the possibility to close sotmata and leaf surface and toaccelerate senescence. However, these adaptive modifications usually havedetrimental consequences such as the decrease of biomass and yield until plantdeath, depending on the strength and duration of the stress. To cope with water excess, plants trigger one of twostrategies, the quiescence and the escape. Quiescence involves a reduction incarbohydrate consumption during a few days to recommence after water drainingand occurs in some species that tolerate complete flooding. On the other hand,the escape strategy consists in the fast elongation of internodes maintaining alow metabolic activity during months to continue with growth and this strategyis triggered by cultivars partially covered with water that overgrow the waterlevel. Both strategies exhibit a few common characteristics such as theemergence of adventitious roots, the formation of aerenchyma and the hyponasticgrowth. When plantsare flooded, both submerged or waterlogged, respiration and photosynthesis aredrastically reduced with a concomitant loss in biomass and yield. Notably,after complete desubmergence and re-oxygenation, plants must overcomedehydration, objective that is not always reached and hence, they die bydrought. Water deficitand excess seem to be opposite. However, the stresses caused by these factorsas well as the responses triggered by the plants to deal with them share severalcommon features.