| Clarify the functional change trends and relationship in the photosynthetic capacity, dry matter and nitrogen production capacity of different functional leaves of three japonica varieties under different nitrogen levels, to identify possible causes of photosynthetic capacity differences of japonica, provide theoretical guidance for high photosynthetic efficiency of rice physiological breeding.By conducting field experiment at four nitrogen conditions were 0N(no nitrogen), 1N(nitrogen 70kg·hm-2), 2N(nitrogen 140kg·hm-2) and 3N(nitrogen 210kg·hm-2) to study the photosynthetic characteristics,leaves source capacity of different functional leaves, dry matter and nitrogen accumulation and transfer rate, nitrogen uptake and utilization rate,agronomic traits and yield of three japonica rice,and relationship between these indexes, the results showed:1.With the increasing of nitrogen levels, plant height, tiller number and leaf area index were significantly improved at filling stage. But different varieties there are significant differences in response to nitrogen fertilizer, and high efficient leaf area of filling stage and yield reached the highest value at 2 N of Jinongda505 and Jinongda 809, 3 N of Jinongda 603.2.Third leaf of three rice net photosynthetic rate(Pn) there are significant differences between different levels of nitrogen, Jinongda 505 reached the highest value at 2N level, Jinongda 603 at 3N level, with increasing of nitrogen levels,Jinongda 809 third leaf Pn did not change significantly.3.At each level of nitrogen level, the total leaf source capacity of three japonica rice at Elongation-Heading stage is the highest.flag leaf source capacity(LSC) of Jinongda 505 reached the highest at Elongation-Heading stage at 2N level, the second leaf at 3N and pour three leaf at 0n reached the highest level; the three functional leaf source capacity(LSC) of Jinongda603 were at jointing heading stage at 3N reached highest value; flag leaf and the second leaf source capacity(LSC) of Jinongda 809 at Elongation-Heading stage of 2N is highest and pour three leaf at 0N reached the highest, indicating that the photosynthetic capability of Jinongda505 and Jinongda809 at Elongation-Heading stage at low nitrogen level had higher photosynthetic capacity, and Jinongda 603 need high nitrogen level in order to improve the photosynthetic capacity.4.Three japonica varieties of dry matter accumulation and transfer rate have different response to different nitrogen levels. Heading to maturation, Jinongda505 stem sheaths and leaf translocation amounts and transfer rate of dry matter at 0N level reached its highest level, and Jinongda 603 stem sheath dry matter transfer capacity with the increase of nitrogen levels were significantly increased and reached maximum at 3N level, Jinongda 809 stem sheath dry matter transfer capacity at 2N level; under the same nitrogen level, the increase of dry matter of panicle performed, Jinongda 505> Jinongda 809> Jinongda 603.5.Different levels of nitrogen has certain influence to nitrogen accumulation of different organs of japonica rice plant, and there exist certain differences between japonica rice varieties. Jointing stage, Jinongda 505 leaf and stem sheath nitrogen accumulation is higher than the other two varieties at 0N level, Jinongda 603 leaf and stem sheath reached highest at 3N, Jinongda 809 stem sheath nitrogen accumulation at 2N reached its highest level.6.From the perspective of the nitrogen utilization ratio, with the increasing of N levels, three japonica varieties physiological utilization efficiency is on the decline; And agriculture utilization under the condition of highest at 2N; nitrogen absorption efficiency of Jinongda 505 and Jinongda 809 were higher than Jinongda 603 at 1N,at 2N and 3 N levels,utilization rate of nitrogen absorption showed, Jinongda 603> Jinongda 809> Jinongda 505.7.Correlation study shows that: tillering to jointing stage, leaf source capacity of third leaf of Jinongda 505 and the total plant dry matter accumulation was significantly positively related, and the total nitrogen accumulation was significantly negative correlation; jointing stage to milking stage, leaf source capacity of flag leaf and third leaf of Jinongda 603 and total dry matter and nitrogen accumulation was extremely significant correlation.In summary, this study suggests that Jilin Province japonica rice varieties Jinongda 505 and Jinongda 809 photosynthetic capacity of lower layer leaves improved under low nitrogen level at heading stage, but Jinongda 603 need high nitrogen level in order to improve the photosynthetic capacity.Appropriate nitrogen fertilization before heading stage could increase the dry matter translocation of stem sheath and leaf, and increase the accumulation of panicle and reach the high yield. The nitrogen use efficiency of Jinongda 505 and Jinongda 809 are better, and can obtain high yield under the condition of low nitrogen;while Jinongda 603 belong to nitrogen sensitive varieties, suitable nitrogen fertilizer can increase the nitrogen absorption and utilization. |
