Study On Phytic Acid P Accumulation Regularity In Maize Seeds And Its Influence Factor

Phytic acid is the primary storage form of phosphorus (P) in cereal grains and phytic acid P accounts for 60~80% of total P in the seeds. Phytic acid P is indigestible for non-ruminant livestocks, for lack of phytase, and it would expel from the stomach with the excrement, resulting in serious P-pollution. The maize qua one important component of the feedstuff, for that reducing the phytic acid P content is significant to decrease the P-pollution. Most of the latest studies are about the low-phytic-acid mutants. Based on the field experiments, this paper compares the characters in seed phytic acid P content with the different maize genotypes, explores the accumulation model of phytic acid P during seed filling, and studies the relationships of P supply, N supply and some agriculture characters to phytic acid P content and accumulation in the maize seeds. The results showed as follows:1. The results of testing phytic acid P content of 50 inbred lines and 24 hybrid seeds showed that, the mean of phytic acid P content in 50 inbred lines was 1.97mg/g, there was the minimum 1.33 mg/g and the maximum 2.67mg/g among them, and the maximum was two times of the minimum. The mean of phytic acid P content in 24 hybrid seeds was 1.81mg/g(1.50~2.30mg/g). This showed that there were significant differences in inorganic P, phytic acid P and total P among different genotypes and there were the material which was the relatively high and low phytic acid P content, which was saying that it was possible that we could find the material of low phytic acid P and high inorganic P from the existing inbred lines and hybrids. Danhuang02 was an inbred line with low phytic acid P, high inorganic P content and excellent agriculture character.2. The result of the relativity of phytic acid P , inorganic P and total P of 50 inbred lines and 24 hybrid seeds showed that phytic acid P and inorganic P are not significant positive correlation. So it is suggested that we should use two indexes (phytic acid P and inorganic P) to select the ideal genotype, because it will be difficult to find the material which is low phytic acid P and high inorganic P solely by using one index.3. There wasn't phytic acid P when the maize seeds begin to develop, but as it was developing, phytic acid P content and accumulation amount increased constantly. The increasing model could be divided into four periods for rapidness-slow- rapidness-slow. Inorganic P content descended constantly with the seeds developing, its accumulation amounts increased in the early, at the late stage, Jinhai5 descended, while Xundan20 kept steady basically. The difference of total P content during seed development was little, and it was steady with slight decline as the whole growth and development period, its accumulation amount increased quickly early while slowly in the late. In the whole developed course, there were well interaction among phytic acid P, inorganic P, total P and weight per hundred seeds.4. In the whole developed of Jinhai 5 and Xundan 20,increasing the P supply rised phytic acid P and total P content significantly. While inorganic P didn't enhance at high P supply.5. The results for the analysis of 174 inbred lines and 2 parents showed as follows, there were significant positive correlation among phytic acid P, inorganic P and total P content, which show that they had well interaction. Increasing N supply could promote phytic acid P content, the mean of phytic acid P was 1.90mg/g at low N supply, distributed between 1.15 mg/g and 2.51 mg/g; the mean of phytic acid P was 2.34mg/g at low N supply, distributed between 1.68 mg/g and 3.07 mg/g. The influnce of different maize breeds' phytic acid P content was diverse. Among 174 inbred lines for test material, phytic acid P conten at high N supply was most reduced 0.29mg/g than low N supply, however, the most incremental value was 1.11mg/g,phytic acid P content at low N supply was higher 0.44mg/g than low N supply, which rised 23%.There are great diversity of influnce of N supply about different genotypes maize.The inverse proportion about the genotypes which increasing and depressing with rising N supply among 174 inbred lines.6.The correlation analysis of phytic acid P content in the seed of maize,plant height,ear thick and ear row showed that the correlation were not significant between phytic acid P content and plant height,ear thick and ear row,respectively.