Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Agronomy, Plant Sciences, Agriculture, root architecture, lateral rooting, root thickness, root plasticity, phosphorus uptake efficiency, water availability, ORYZA-SATIVA L., ACQUISITION EFFICIENCY, DROUGHT RESISTANCE, VEGETATIVE-STAGE, DEFICIT STRESS, TOLERANCE, NITROGEN, GROWTH, PLANTS, MAIZE, C16/15/042#53326572, 0502 Environmental Science and Management, 0703 Crop and Pasture Production, 3002 Agriculture, land and farm management, 3004 Crop and pasture production

Abstract:

© 2018 by the authors. Drought and low phosphorus (P) availability are major limitations for rainfed rice production. Crop roots are important for soil resource acquisition and tolerance to P and water limitations. Two pot and two field trials were conducted to evaluate architectural root responses of contrasting rice varieties to combinations of different levels of P (deficient to non-limiting) and water availability (water stressed to submergence) and to identify the interactions with different varieties. Root development was then related to drought and/or low P tolerance. Although shoot and root growth responded more to P than to water availability, architectural root responses to water were much more prominent than responses to P availability. Reduced water availability decreased nodal thickness and increased secondary root branching, both factors partially enhancing P uptake efficiency and even overcoming a decreased root:shoot ratio under reduced water availability. In contrast to root thickness and secondary branching, basal lateral root density was strongly determined by variety and was related to enhanced P uptake. Reduced water availability induces root modifications which—apart from enhancing drought resilience—also affect P uptake efficiency. Future research on rice roots and nutrient uptake may hence take into account the large effects of water on root development.