| With the increase of population and the decrease of arable land, it has been an important way to increase crop yields and use of limited resources efficiently for the sustainable development of agriculture in China. Phosphorus plays important roles in promoting plant growth and development. Thus, selecting and breeding genotypes with high phosphorus utilization efficiency have become the main research directions to improve nitrogen utilization efficiency in rice. But in practical production, the contradiction between rice yield and phosphorus utilization was not well coordinated, and the mechanism of phosphorus absorption and utilization was even not clear. In this paper, the pot, field and hydroponics experiments were carried out on the farm of Sichuan Agricultural University, Sichuan province, China in 2011 to 2013, by using rice genotype with high phosphorus utilization efficiency as the experimental materials, rice genotype with low phosphorus utilization efficiency as the contrast materials. The purpose of this article was to ascertain the mechanism of phosphorus efficient utilization through the analysis of phosphorus absorption, accumulation and distribution characteristics, besides propose possible control measures to synergistically improve rice yield and phosphorus utilization efficiency. The main results were as follows:(1) Twenty seven of middle-season and twenty nine of late rice cultivars were taken as testing materials, their genotypes were assigned into three groups of I, II, III by least square and dynamic clustering method. The biomass and phosphorus absorption were investigated in different growth stages for various yield types using field experiment. There was extremely significant genotype differences in rice yield, phosphorus absorption and use efficiency among the rice cultivars in different growth stages. The maximum yields were 3.24 and 2.15 times higher than the minimum yields for data obtained from middle-season rice and late rice, respectively. The difference was no significant in phosphorus use efficiency between them. The largest phosphorus accumulation was in tillering-jointing stage for middle-season and in jointing-heading stage for late in I rice. There is not much dry matter accumulation in tillering-jointing stage, the largest accumulation was in jointing-heading stage for both the middle-season and I rice. Dry matter and phosphorus accumulation during tillering-jointing stage played main role in yield of middle-season rice with the highest contribution rate to yield of up to 42.38% and 58.09%, respectively. The phosphorus accumulation during heading-maturing stage is important in yield of late rice with the highest contribution rate of up to 39.35%, and 16.16% of the dry weight was accumulated in this stage. In conclusion, the cumulative dry matter during tillering-heading stage and phosphorus absorption during tillering-jointing stage play key role in yield formation of middle-season rice, the cumulative dry matter in early stage and phosphorus in late stage are important to the yield of late rice.(2) Combined with the test results of two years, there were significant genotype differences in high phosphorus efficiency of the materials. GR77 was selected as high phosphorus efficiency materials. At the two phosphorus levels, high phosphorus efficiency of GR77 were higher than that of 08B-9643. Yield of GR77 were 1.96 and 1.92 times higher compared with that of 08B-9643, respectively. The field and pot experiments showed that the contribution rate of phosphorus accumulation to yield in rice was greater than that of phosphorus grain production efficiency and phosphorus harvest index. The contribution rates of phosphorus accumulation and phosphorus grain production efficiency to yield had no significant difference in rice grown in soil with normal phosphorus application, whereas obvious differences were observed at low phosphorus condition (66.53% and 26.62%). The minimal contribution to yield was phosphorus harvest index and the rate was only 11.78%. At normal phosphorus condition the contribution rates of phosphorus accumulation to yield and phosphorus harvest index were the highest at jointing-heading stage, which were 93.39% and 85.71%, respectively. In addition, the contribution rate of phosphorus accumulation to grain production efficiency was 41.80%. At low phosphorus condition, the maximal contribution rates of phosphorus accumulation to high production efficiency were observed at tillering-jointing stage, which were 56.91% and 20.05% respectively. Furthermore, the contribution rate of phosphorus accumulation to phosphorus harvest index was 15.98%. At normal phosphorus conditions, the yield, phosphorus accumulation, and phosphorus harvest index of GR77 significantly increased by 20.55%,18.10% and 18.24% respectively compared with low phosphorus condition. The rank of the contribution rates of phosphorus efficiencies to the yield was as follows: phosphorus uptake efficiency> phosphorus utilization efficiency> phosphorus transportation efficiency. The greatest contribution rate of phosphorus accumulation to the yield was noticed at jointing-heading stage with normal phosphorus application while it reached the maximal value at tillering-jointing stage with low phosphorus application. Therfore, these two stages may be the critical periods to coordinate high phosphorus efficiency in rice.(3) High phosphorus efficiency GR77 root bleeding sap were significantly higher than the phosphorus-inefficient genotype, root bleeding sap of each mineral substance, the two types of rice genotypes bleeding sap the main difference is the mineral component of P, K, Mg, Fe is the difference between, Zn and Ca is almost no difference, phosphorus efficient genotypes of rice xylem sap Fe content of phosphorus in the two treatment conditions were significantly higher phosphorus inefficient rice genotypes, phosphorus inefficient genotypes 1.53 and 1.44 times. Amino acid differences in the two types of rice genotypes exudates of low phosphorus treatment was not significant, when the normal processing of phosphorus phosphorus efficient genotypes is 1.21 times the phosphorus inefficient rice genotypes, phosphorus efficient genotypes of rice roots to propionic acids secreted acid-based, its secretion was 23.36%-29.44%, and the effect on the maximum amount of phosphorus accumulation in rice. |
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