Effect of intercropping on leaf senescence related to physiological metabolism in proso millet (Panicum miliaceum L.)

Abstract

The field experiments were conducted to explore the changes in metabolism related to leaf senescence in proso millet (Panicum miliaceum L.) under proso millet/mung bean intercropping system. Results showed that intercropping increased leaf photosynthesis, as measured by the increased net photosynthetic rate and chlorophyll content, maximum photochemical efficiency of PSII, and decreased nonphotochemical quenching coefficient. These responses resulted in the increased leaf number and area and reduced yellowing leaf rate; leaf photosynthetic capacity was maintained for longer periods. Such improvements occurred due to enhanced activities of protective enzymes (superoxide dismutase, catalase, peroxidase) and lowered malondialdehyde and superoxide radical contents. This conclusion was supported by the increased N metabolism in leaves. The grain yield was stimulated by 6.8-37.3% compared to the sole system. Intercropping patterns would delay proso millet leaf senescence and increase grain yield in this region.

Keywords

• antioxidant system; chlorophyll a fluorescence; gas exchange; glutamine synthetase; leaf area; nitrate reductase.