In wheat, pea, barley, broad bean and rape, the photosynthetic capacities in the leaves of plants acclimatized to a higher temperature (20–25°C) were much higher than those in the same plants grown at low outdoor temperatures in winter (meanair temperature, 5–7°C). On transferring the cold-grown wheat plants (vats, 5–7°C) to the higher temperature (25/20°C), the Photosynthetic rate of laves remained unchanged for the first 8 hr, then gradually increased to attain after 16 hr a maximum level which was the same as that in wheat plants grown at the higher temperature (growth box, 20–25°C). When intact wheat without soil was taken from the cold winter field and the attached leaves were placed in the chamber at 25°C, the Photosyntheic rate of the attached leaves increased sluggishly for 2 hr, then remarkably increased to attain the maximum level 9 hr afer transferral to the chamber. When the leaves detached from wheat grown in the winter field were transferred to the assimilation chamber kept at 25°C, the rate started to increase without a lag period and attained the maximum level within 3 hr. The optimum temperature for photosynthesis shifted in parallel with the rise of air temperature under which the wheat had been grown. The slopes of increase in the photosynthetic rates with increasing intensity of illumination wwere practically the same in wheat grown under different temperatures. It was found that the total amount of sucrose in wheat grown at low temperatures in the winter was higher than that in those grown at the high temperature.
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Sawada et al. (1974) studied this question.