Effects of nutrient supply on the photosynthesis of maize hybrids

Abstract

Light and nutrients are two essential factors that plants must have to grow and forming yield. The aim of our work is to add some information about the yield forming procedure of maize. Taking leaf gas exchange measurements not in a laboratory but in the field has great significance. We measured the assimilation parameters of maize hybrids in field trial on the nutrient supply. Lonhardne et al. (1996) investigated the photosynthetic potential in nutrient supply experiments. The photosynthetic potential depended on the nutrient levels. Bindraban (1999) wrote that in his observations the photosynthesis in the lower leaves of wheat depended mainly on the light intensity. The effect of nitrogen supply was low. Shangguan et al. (2000) agreed that the nitrogen and water supply has great affect on the photosynthetic gas exchange. The higher nitrogen supply lowered the water use efficiency of the plants and the net photosynthetic rate decreased. Janda et al. (1998) studied photosynthetic activity of maize plants under different environmental conditions. They estimated that there were no differences between net photosynthetic rate of genotypes in optimal temperature but in lower temperature there were differences. In the experiments in California Hirasawa et al. (1999) found that the leaves reach the maximum photosynthesis rate in the morning on droughty days in spite of that the soil was irrigated. Sharma et al. (1998) established that the UV-B light significantly decreased the net photosynthesis in the leaves of the wheat.