GROWTH, PHYSIOLOGICAL AND ANATOMICAL RESPONSES OF 2 WHEAT GENOTYPES TO WATERLOGGING AND NUTRIENT SUPPLY

In order to investigate the responses of plant genotypes to waterlogging and nutrient supply, physiological, morphological, and anatomical features were determined for two genotypes of winter wheat (Trificum aestivum), 'Bayles' and 'Savannah'. Plants were grown in a growth chamber and fertilized with half-strength or full-strength Hoagland's solution during 17 d of waterlogging. Waterlogging reduced leaf water potential, stomatal conductance, photosynthesis, chlorophyll content, shoot nitrogen content, shoot and root growth for both Bayles and Savannah; however, there were more adverse effects on Bayles than on Savannah. Doubling the concentration of nutrients supplied to the waterlogged rooting medium reduced the rate of decline in photosynthesis, chlorophyll content, number of nodal roots, and improved shoot nitrogen status and growth, especially for Bayles. Waterlogging reduced the diameter of metaxylem and protoxylem vessels of the nodal roots for both genotypes. Waterlogging enhanced the formation of aerenchyma in the cortical tissue of both seminal and nodal roots, but to a greater extent for Savannah. Additionally, aerenchyma formed continuously along the seminal roots in Savannah. The results indicated that Bayles was more sensitive to waterlogging than Savannah and that increases in nutrient supply to waterlogged plants could alleviate some of the adverse effects of waterlogging.