Study On Nitrogen-use Characteristics And Changes Of Sink- Source Of Rice Cultivars In Different Years

This experiment researches on leaf nitrogen content,leaf photosynthetic characteristics, plant biomass and yield of 33 rice varieties in different years,aims at identifying the relationship between the changes of nitrogen-use characteristics and yield formation and exploring the feasibility of photosynthetic nitrogen use efficiency as the assessment of the of nitrogen use efficiency index in order to provide research direction for the study on the physiological mechanism of rice and theoretical basis for rice breeding and reasonably efficient nitrogen fertilization yield cultivation techniques.1、The total nitrogen content in the leaves of different rice varieties breed with advancing age and show an increasing change in the heading and heading 10 d, rice leaf nitrogen content and breeding age is highly significant or significant positive correlation; nitrogen content per unit leaf area with breeding age increment after heading and heading 10 d and breeding age are highly significant positive correlation. Different rice varieties chlorophyll content in the 30 d after heading, and breeding age is a significant positive correlation; different rice varieties advancing age SLW with incubation show an increasing trend, after heading 10 d, specific leaf weight and breeding age is a significant positive related. The nitrogen content of the rice plant leaves are improved by genetic improvement of rice varieties.2、There was a significant or high-significant correlation between leaf total nitrogen content and yield at heading and 10 d after heading in different rice varieties; nitrogen content per unit leaf area and yield also showed the same changes in relationship: a significant positive correlation was found between chlorophyll content and yield of different rice varieties from heading to 30 d after heading. It is suggest that chlorophyll content will help improve yields. Chlorophyll is closely related to leaf nitrogen content which is closely associated to the yield at heading and 10 d after heading. Overall, high nitrogen translocation and utilization ability is the key point to obtain high production of rice.3、Analysis of different rice varieties in the 30 d after heading, rate of change and variety breed’s net photosynthesis of rice varieties leaf 4 growth stages show that rice leaves at different growth stages of net photosynthetic rate and varieties bred age is positively correlated, 10 d reach significant level after heading, the heading stage, 20 d 30d after heading do not reach a significant level, during the genetic improvement of rice varieties, the net photosynthetic rate of rice leaves is significantly increased especially 10 d rice leaf net photosynthetic rate after heading is increased most obviously.4、After Comparing and analyzing various photosynthetic parameters during four different rice varieties, we find that 10 d after heading varieties of rice is an important period of development, which plays a major decisive role in operation and distribution of photo synthetically, research on the relationship between research output also find that, 10 d after heading, rice leaf photosynthetic characteristics and yield are significant positive correlation, and the correlation coefficient is significantly higher than other growth stages, indicating 10 d after heading is the key to impact varieties of rice yield formation period.5、The genetic improvement of rice production in Jilin Province during the course of 51 years, yield and harvest index are increased, rice plant biomass is increased as well, increased plant biomass is the result of increased rice leaf sheath and stem biomass, among which, increase leaf biomass is the most significant, rice of leaf and stem biomass 10 d after heading are most significantly associated with the production, 30 d after heading, plant biomass and yield related are most significant, especially biomass rice leaves after heading and 10 d after heading the stem and leaf sheath are closely related to biomass production, which can be used as selection indicators of high-yielding varieties.6、Research on rice leaf nitrogen content, net photosynthetic rate and leaf biomass plant relationships suggest that the net photosynthetic rate in rice leaf nitrogen content and leaf except at heading is positively correlated, while they have negative correlation in the 10 d to 30 d after heading; net photosynthetic rate of the plant biomass has a decisive role, and with the age and fertility bred Promote This role has become increasingly obvious; leaf nitrogen content on the performance of plant biomass is 10 d after heading and heading for negative correlation is stronger than the modern varieties of early varieties, after heading and heading back 20 d 30d, leaf nitrogen content and plant biomass is positively correlated. Rice in the late childbearing accumulates dry substances, leading to increased production, our experimental results show that nitrogen accumulation ability is the key to improve photosynthesis.7、Nitrogen photosynthetic efficiency and agronomic use efficiency in rice leaves at heading stage show a significant positive correlation between nitrogen use efficiency and nitrogen agronomic efficiency, there is a significant positive correlation between nitrogen use efficiency and nitrogen photosynthetic efficiency, it is significantly positive relationship 10 d after heading and 20 d after heading, agronomic efficiency and Photosynthetic Nitrogen use efficiency show highly significant or significant positive correlation 30 d after heading, agronomic efficiency and nitrogen use efficiency show a significant positive correlation. The results show that the correlation heading date of rice leaf photosynthetic efficiency of nitrogen, nitrogen agronomic efficiency and nitrogen use efficiency is most closely related, which can be heading date of rice leaf photosynthetic efficiency of nitrogen species as an indicator of nitrogen efficient screening.8、The source library traits are improved during the rice genetic improvement in Jilin Province, the increase in production is the result of source-sink working together. Ear weight / Pn and grains / Pn are bred with age and show a significant increase in the trend, which shows that the genetic improvement of rice varieties in the growth process, Pn is far behind the growth of grains per panicle weight and, Pn may be restricted rice an important factor in species production. Rice breeding in the future work should further focus on improving net photosynthetic rate of leaves, improve plant photosynthetic capacity per unit leaf area, this results has certain theoretical and practical significance for the future new high-yielding rice varieties breeding and high yield cultivation techniques.