Stem reserve mobilisation supports wheat-grain filling under heat stress. [Workshop paper]
1994
Blum, A. | Sinmena, B. | Mayer, J. | Golan, G. | Shpiler, L. (Volcani Centre, Bet Dagan (Israel). Inst. of Field Crops)
Two spring wheat cultivars (V5 and V2183) of very similar phenology and plant stature, which had previously been found to differ in grain shrivelling under drought and heat stress conditions in the field, were used to evaluate the hypothesis that the mobilisation of stored stem reserves into the growing grain is an important source of carbon for supporting grain filling under heat stress. In 2 experiments in Israel (1990 and 1991), the rates of stem dry matter (DM) and stem total non-structural carbohydrates (TNC) loss, grain growth and leaf senescence were monitored under optimal (control) and high (stressed) temperatures in the glasshouse (1990) and the growth chamber (1991). Cultivar V5 always sustained a smaller reduction in grain dry weight under heat stress, than V2183. Irrespective of temperature, V5 had a higher stem DM and TNC content at the onset of grain filling, greater depletion of stem dry matter (or TNC) during grain filling, and longer duration of grain filling, than V2183. In a third experiment, 5 cultivars were subjected to heat stress (35/25 deg. C) or non-stressed (25/15 deg. C) conditions after anthesis in a growth chamber. Grain dry weight reduction by chemical desiccation was highly correlated with grain dry weight reduction by heat stress.
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