Effects of phosphorus on the plant growth, phosphorus cycling and distribution in different maize cultivars

Phosphorus cycling and recycling is important for maintaining plant growth and enhancing P use efficiency. Two maize (Zea Mays L.) hybrids, Liyu 16 and Jidan 28, were used as the testing materials. Two P levels: high (250 mol/L) and low (5 mol/L) was set up under the conditions of sand and nutrient culture. Dry weight and P content in each organ, P cycling and flowing between xylem and phloem, P uptake and use efficiency were studied. The results showed that during the study periods, compared with highP treatments, lowP significantly depressed dry weight and P content in each plant organ and P transported in the xylem, while increased P retranslocated from leaves to the root by phloem. P activated in each leaf organ were recycled to roots through phloem, and then transported to the upper new leaves via xylem. Moreover, assimilation was not synchronized with P transportation to upper leaves. Compared to Jidan 28 cultivar, Liyu16 cultivar had higher ratio of root to shoot, dry weight, P content, P uptake efficiency, P use efficiency, P proportion from xylem transported into the upper leaves, accounting for 010, 269%, 120%, 121%, 133% and 306%, respectively under the lowP. In conclusion, the biomass of P-highefficiency maize cultivar under the lowP was higher which was partially attributed to its higher ratio of root to shoot, more P transported to upper leaves in the xylem, higher P uptake and use efficiency.