Inclination Response of Leaf Blade in Wheat Varieties under Monochromatic Lights

Abstract

Thirty-two varieties of wheat plants (Triticum aestivumL.) were cultured on vermiculite under various monochromatic lights, white light or darkness at 20°C for 12 days. The lengths of the sheath or blade and the angle of blade inclination of the first leaves were compared to culm length in adult plants grown under field conditions.1) Considerable differences in sheath and blade lengths were found among the varieties under all the light or dark conditions. The sheath and blade lengths under experimental conditions were positively correlated with the culm length in adult plants under field conditions.2) Under blue irradiation, blade inclination was promoted in all varieties, and the inclination angles were about 100°. Under red and white lights, there were remarkable differences in inclination response among the varieties. Blade angles showed a positive correlation to the culm length in adult plants grown under field conditions. Correlation coefficients of the blade angle to culm length were 0.863 in red light and 0.607 in white light. The relations between blade angle and the sheath or blade length under experimental conditions were similar to those for culm length. Under green light and darkness, there was scarcely any blade inclination in any of the varieties.3) The detailed examination of the relation between the blade inclination angle and culm length under red light showed that the wheat varieties used could be classified into two groups. Blade inclination response was promoted in wheat varieties with a culm length of 100 cm or more, but was scarcely promoted in those with culm length of less than 100 cm. In the former group, blade angle and culm length had a positive correlation.