Nitrogen supply to the grain modifies the effects of temperature on starch and protein accumulation during grain filling in wheat

Abstract

Effects of nutritional status on the responses to high temperature of 2 wheat cultivars that differed in their sensitivity to high temperature were investigated in plants grown in pots in environmentally controlled growth rooms. The availability of nitrogen to the grains was altered by changing the amount and timing of the nitrogen supplied to the plants, and also by trimming the ears. Single grain weight was significantly decreased in the plants grown at 30/25�C compared with those grown at 20/15�C. The effects of nitrogen level or trimming on the response of grain filling to temperature did not seem to be mediated through alterations in the availability of carbohydrates within the grains. Neither N level nor trimming had substantial effects on the deposition of starch, but both treatments altered the accumulation of protein, and the responses of protein accumulation to the effects of temperature.