Oxygen use from solution by wheat genotypes differing in tolerance to waterlogging

Inadequate availability of oxygen to theroots is a major growth-limiting factor forplants exposed to waterlogging stress. Spring bread wheat genotypes (Triticumaestivum L.) have been found to differ intheir tolerance to waterlogging. Threespring wheat genotypes tolerant towaterlogging (Ducula, Prl/Sara, andVee/Myna) and two sensitive spring wheatgenotypes (Seri-82, and Kite/Glen) wereevaluated for differences in root anatomyand O^sub 2^ depletion rates from nutrientsolution in growth chamber experimentsconducted under both aerobic and hypoxicconditions. Plants in the aerobictreatment were grown for four to five weeksunder continuous aerobic conditions. Plantsin the hypoxic treatment were initiallygrown aerobically for two to three weeksfollowed by two to three weeks of hypoxicconditions. The percent root porosityranged from 12 to 20% (v/v) for tolerantgenotypes and from 6 to 8% for sensitivegenotypes grown under hypoxic conditions.Decreasing O^sub 2^ supply increased therate of O^sub 2^ uptake in waterloggingtolerant cultivars. Anatomical differencesin root structure between tolerant andsensitive genotypes could not be related toobserved differences in O^sub 2^ use. Although inconclusive, the results suggestthat in addition to oxygen transport, themovement of photosynthate to the rootsunder waterlogged conditions may also beimportant in conferring tolerance.[PUBLICATION ABSTRACT]