Drought and low P availability are major limitations for rainfed rice (Oryza spp.) production. Root anatomy plays a key role in resource acquisition and tolerance to P and water limitations. Root anatomical responses of three contrasting rice varieties to combinations of different levels of P (deficient to non-limiting) and water availability (water stress to submergence) were evaluated in two pot trials. P availability was the dominant growth-limiting factor, but anatomical root responses to water availability were more prominent than responses to P availability. Cortical cell file number and number of xylem vessels decreased as a response to water stress, but stele and xylem diameter increased. Low P availability induced thinner xylem vessels and a thinner stele. Drought tolerance related to an overall thicker root stele, thicker xylem vessels and a larger water conductance. Some root traits were observed to be more responsive to water and P availability, whereas other traits were more robust to these environmental factors but highly determined by variety. The observed genotypic variation in root anatomy provides opportunities for trait-based breeding. The plasticity of several traits to multiple environmental factors highlights the need for strategic trait selection or breeding adapted to specific target environments.
Anatomical root responses of rice to combined phosphorus and water stress – relations to tolerance and breeding opportunities.
Citation: Bauw, P. D.; Vandamme, E.; Lupembe, A.; Mwakasege, L.; Senthilkumar, K.; Dramé, K. N.; Merckx, R. 2019. Anatomical root responses of rice to combined phosphorus and water stress – relations to tolerance and breeding opportunities. Functional Plant Biology. ISSN: 1445-4408. 46(11). 1009-1022