Author:
Savin Roxana,Stone Peter J.,Nicolas Marc E.,Wardlaw Ian F.
Abstract
Short periods of very high maximum temperature (>35°C) during grain
filling appear to reduce grain yield and quality in barley. Tolerance of grain
yield and quality to heat stress may be increased when acclimation to high
temperature occurs. Two experiments were performed to test the hypothesis that
a gradual (or stepped) increase to very high temperature reduces the impact of
that stress on grain growth and quality of barley, compared with a sudden
increase over the same temperature range. Plants experiencing either a sudden
or a gradual increase did not exhibit any differences in grain weight or
malting quality, but increasing the temperature in 2 steps (so that plants
were exposed to 30 or 34°C for 2 h before a 40°C heat stress) appeared
to have produced acclimation, since the reduction in grain weight under the
2-step treatment was about half that of either a sudden or gradual increase in
temperature.
Heat stress altered grain composition in various ways. The reduction in final
grain weight was strongly and linearly related to the reduction in starch
content. Grain β-glucan was 4·5 ± 0·5% across
treatments and experiments and was significantly reduced in the glasshouse but
not in the phytotron experiment. However, β-glucan degradation was similar
between treatments in both experiments. Grain nitrogen concentration was very
high and similar between treatments. Consequently, diastatic power was high
and there was a trend towards a reduction under heat stress. Free amino
nitrogen was higher under heat stress, indicating a higher protein
modification than in the controls. Malt extract was significantly reduced by
heat stress in the glasshouse experiment.
Subject
General Agricultural and Biological Sciences
Cited by
15 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献