Phosphorus Stress Tolerance To Low Phosphorus A Preliminary Study Of The Physiological And Biochemical Characteristics Of Corn Inbred Lines

The physiological and biochemical characteristics of the low-phosphorus tolerance maize inhybrid lines, 99043 and 99038 acquired by cell engineering technology and the skeleton maize inhybrid line, Qi319 were investigated under both solution and sand culture conditions. The primary purpose of these studies is to elucidated the possible mechanisms of the low-phosphorus tolerance maize lines and cultivate Pi high efficiency germplasm.hi the sand culture experiments, 99043 and Qi319 were grown in the plastic pots for 35d, The seedlings were watered with high (+P, 1000uM Pi) and low (-P, Pi deprived of) Pi nutrient solutions every day. The results indicated that the differences in the absorption, transition and utilization efficiency of P between Qi319 and 99043.were obvious. Under -P condition 99043 had advantages in root dry weight, total root length, total area, root apex number and root diameter compared with Qi319. Furthermore, 99043 also was advantageous in total uptake area, active uptake area, Imax, Km and Cmin. These data demonstrated that 99043 had higher P absorption and P utilization efficiency than Qi319 under -P condition.Sand pot experiments were carried out to study the mobilization and uptake of phosphorus compounds (K-P, Ca-P, AI-P and Fe-P) as affected by some physiological and biochemical features with different maize inhybrid lines(99043, 502 ).The differences of P uptake and utilization under different P treatment between 99043 and P sensitive inhybrid line 502 with sand culture were investigated. The result showed that there were marked differences in the mobilization and uptake of different P compounds between 99043 and 502.Using insoluble phosphates as the sole P source, 99043 had higher biomass. 99043 also had higher activation ability of three insoluble phosphates. Therefore, 99043 may be more adaptive to the soil with higher insoluble phosphate.The activities of root and leaf APase and the P content of 99038 has been monitored in solution culture experiment. The results showed that with the deepening of P stress, the ratio of APase activity under -P relative to that under +P conditions increased obviously. Under -P condition, the APase activities of 99038 root base and old leaves were higher than those of root apexes and new leaves. It is thought that APase plays an important role in the release of organic P, therefore, the enhanced APase activity under P stress contributed to the...