1994 Volume 63 Issue 4 Pages 699-705
Leaf movement of field-grown soybeans under water stress conditions was examined with radiation interception. Two cultivars with different leaf movement, Zhenzhuta 2 (active) and Heinong 33 (inactive), were grown in concrete plots in Xingjiang, China. At the pod filling stage, the plants were subjected to four different levels of irrigation. Intercepted radiation of every leaflet of two plants in each plot was measured by integrated solarimeter films for 2 days. There were large varietal differences in leaf movement affecting radiation interception. The upper leaves of Zhenzhuta 2 tended to intercept greater amount of radiation and the efficiency of radiation interception against leaf area was higher, as the amount of irrigation increased, indicating that paraheliotropism in the morning was inactive due to the water supply. Heinong 33 did not differ in radiation interception among the treatments except in the severest water stress plot. Radiation in the severest water stress plot penetrated less because of the wilting of the leaves during the day time. Paraheliotropic movement in Zhenzhuta 2 became inactive in the morning, after the temporary irrigation following the water stress treatments. Heinong 33 recovered from wilting and moved its Leaves paraheliotropically during the day time.
