Studies on Matter Production in Wheat Plant

IV. After-effects of low night temperature on daytime photosynthesis examined under controlled conditions

Abstract

After-effects of low night temperature on photosynthesis in the following daytime were examined under controlled conditions. The results obtained are summarized as follows:
1. Night temperature affected two aspects in daytime photosynthesis; one was the time required for photosynthesis to attain a plateau after the beginning of illumination and the other was the height of this plateau. Low night temperature lengthened the time and also lowered the plateau.
2. The above mentioned after-effects of low night temperature were most remarkable in case both air and soil temperatures were low.
3. Low air temperature alone also brought about the two kinds of after-effects.
4. Low soil temperature alone did not seem to bring about the after-effects. However, in case it combined with low air temperature, it strengthened the effect of low air temperature on the time required for photosynthesis to attain a plateau.