Anatomical root responses of rice to combined phosphorus and water stress – relations to tolerance and breeding opportunities.

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.

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
2019-12-09
BLOOD VESSELS, DROUGHT STRESS, GROWTH FACTORS, PHOSPHORUS, RICE, ROOTS
BIODIVERSITY FOR THE FUTURE, CLIMATE CHANGE

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