Effects of Water Supply and Light Intensity on the Growth of Spring Wheat

The effects of water supply and light intensity on the growth of spring wheat (Triticum aestivum L.) was studied under carefully controlled conditions. The leaf water potential (LWP) was measured from 5 to 40 d after the initiation of water supply treatments (DAIT) . The LWP decreased as DAIT progressed. At higher photosynthetic photon flux densities (PPFDs), the LWP decreased as the water supply decreased. The water supply rate had little impact on tiller initiation and survival under low PPFD. As the PPFD increased, however, tillering responded sharply to water supply. Differences in tiller numbers were mainly due to differences in the number of subtillers from T0, T 1 and T2 primary tillers. The water supply rate did not affect plant growth significantly under low PPFD. Increased PPFD resulted in increased plant growth, except for leaf numbers per main stem, as water supply rate increased. Thus, there was a highly significant interaction of water supply and light intensity on the growth of spring wheat.