Root anatomical traits influence water stress tolerance in rice (Oryza sativa L.)

Though a lot of research was carried out pertaining to above ground traits in relevance to mitigating adverse effects of water stress; however, root traits play a dynamic role in acquisition of water and mineral nutrients from the soil suggesting greater emphasis for a sustainable crop production under water stress environments. For instance, under water deficit, plasticity in below ground traits viz., root morphology and anatomy determine the water acquisition capacity of the plant. In the current study, initially 35 genotypes were evaluated for various morpho-physiological and yield traits at 100 and 50% available soil moisture content. Results of Principal Component Analysis reveals that under stress, stomatal conductance, and photosynthetic rate in PC1, plant height and leaf temperature in PC2 attributed to maximum variation. A narrowed down sample set of six genotypes comprising three tolerant and three susceptible were further evaluated for anatomical and morphological investigations on roots at their respective booting stage. Root length, diameter, stele diameter, metaxylem number, width and ratio of stele diameter to root diameter ratio were varying significantly (p < 0.05) for drought tolerant and susceptible genotypes. This study revealed that drought tolerant genotypes had better root plasticity in terms of metaxylem number and stele diameter compared to susceptible genotypes. This provided maintenance cost under water-limited conditions and produced a satisfactory yield by efficient uptake and utilization of available soil moisture. © 2022, The Author(s), under exclusive licence to Korean Society of Crop Science (KSCS).