Abstract:

【Objective】 The objective of this study was to elucidate the physiological mechanisms of the maize hybrids under P deficiency condition, and to provide a scientific evidence for extension and utilization of cultivars with higher yield and efficiency. 【Method】 Three maize hybrids, Liyu 16, Jidan 28, and Kuancheng 10, were used as the testing materials and subjected to two phosphorus levels: sufficiency and deficiency. Effects of P deficiency on plant development, root morphology, activity and physiological characters were investigated among three cultivars at the seedling stage in hydroponic culture. 【Result】 The results showed that under P-deficient condition, the height, dry weight and P content increment in shoot and whole seedling all decreased while the dry weight of roots and ratio of root to shoot increased. Moreover, root length enhanced by 61%, 62%, and 17%, root radius depressed by 19%, 29%, and 4%, and root surface area increased by 31%, 18%, and 13%, respectively, compared with plants with P. Total uptake area and specific surface area of roots were both low, and pH in the nutrient medium respectively reduced by 1.3, 0.8, and 0.7 units, but the three cultivars all had higher uptake kinetics of H2PO4? and stronger abilities to endure P deficiency. The acid phosphatase (APase) activities in root tissue were improved. However, there were still significant differences among the cultivars. 【Conclusion】Compared with Jidan 28 and Kuancheng 10, Liyu 16 had higher dry weight increment, root length and root surface area, root activity and proton exudation, stronger tolerance ability to P deficiency, larger uptake kinetics of H2PO4– and APase activity in root tissue.

Key words: maize hybrids, P deficiency, physiological mechanism, difference among cultivars