Researches On The Physiology Mechanism Of Grain Filling In Rice By Phytochrome Regulations

Light is one of the most significant environmental factors that influence plant growth and development.It not only provides a source of energy for plant growth and development, but also plays an important role in regulating plant photomorphogenesis.Plants accept the light signal through its photoreceptors.Phytochrome is one of the most photoreceptors in plants and it senses red and far-red light.In this study,the field experiment uses the conventional japonica rice varieties Xinfeng2as the test material, exploits continuous red-light to irradiate the rice in night,and makes the natural conditions as controls.For the problem of poor inferior grains plumpness in rice,we mainly use the FQ-PCR SYBR-Green and ELISA of plants hormone methods to research the physiological mechanism of difference caused by differences in inferior grain plumpness systematically in depth from the relative expression of phytochromes genes and starch synthase genes and the content of plant hormone etc.aspects.The results as follows:1.Effects of Night red-light treatment on yield、yield components and grain plumpness,the results show:through Night red-light treatment,the yield of Xinfeng2declines,and the differences between treatments reach a significant level.The night red-light treatment on yield reduction is mainly manifested in the reduction of the1000-grain weight of superior grains and inferior grains and grains plumpness.2.Effects of Night red-light treatment on the content of plant hormone and grain plumpness in superior grains and inferior grains of rice in the day and night, the results show:through Night red-light treatment,the content of ZR in rice grains declines,and the differences between treatments reach a significant level; the content of ABA in inferior grains of night declines,and the differences between treatments reach a significant level;the content of IAA in rice grains of day and inferior grains of night declines, and the differences between treatments reach a significant level; the content of GA in rice grains of day and superior grains of night rises but not reach significant.3.Effects of Night red-light treatment on the content of the flag chlorophyll in the day and night, the results show:through Night red-light treatment,the content of Chla、Chlb in flag of day declines,and,the content of Chla、Chlb in flag of night rises.The Chla/b value rises at day and declines atnight.The content of total chlorophyll (a+b) rises.4.Effects of Night red-light treatment on relative expression of phytochrome genes in flag of rice day and night, the results show:the photochrome genes consisting of PhyA、PhyB and PhyC do have a relatively reduced expression in rice flag of night at the6th、18th and24th after treatment.Through correlation analysis with the content of plant hormone in rice grains,we found that there is significantly positive correlation between the expression of PhyB genes in rice flag and the content of ZR in inferior grains of rice,and there is significantly positive correlation between the expression of PhyB genes in rice flag of night and the content of GA in inferior grains of rice at night.5.Effects of Night red-light treatment on relative expression of phytochrome genes in superior grains and inferior grains of rice day and night, the results show:with the different treatment days,the change trend of relative expression of photochrome in rice grains showed: PhyA>PhyB, PhyC>PhyB, so the relative expresion of PhyB is the lowest in the different days of treatment. Through correlation analysis with the relative expression of phytochrome genes in flag of rice,we found that there is significantly positive correlation between the expression of PhyB genes in rice flag of night and the expression of PhyA、PhyB and PhyC genes in superior grains of night,in the meanwhile,we found that there is significantly positive correlation between the expression of PhyB genes in rice flag of day and the expression PhyB genes in inferior grains of day.Frome the above that the relative expression of photochrome in rice flag and grains has certain synergistic effect.In the correlation analysis, significantly negative correlation exists between the expression of PhyB genes and the content of ZR in inferior grains of rice in night.6. Effects of Night red-light treatment on relative expression of starch synthase genes in superior grains and inferior grains of rice day and night, the results show:starch synthase genes do have a relatively reduced expression at large in rice grains of night and the inferior grains of day, and along with the increase of treatment days,the number of starch synthase genes the relatively expression increase gradually, and mostly in the18th and24th days of treatment.The reduced relative expression of starch synthase genes is bad for grains filling. Through the correlation analysis with the relative expression of phytochrome genes in flag of rice, we found that there is significantly positive correlation between the expression of PhyB genes in rice flag and the expression of mostly starch synthase genes in grains of rice. Through the correlation analysis with the relative expression of phytochrome genes in grains of rice, we found that there is significantly positive correlation between the expression of phytochrome genes and the expression of some starch synthase genes, and the relative expression of PhyB genes impact wider. Through the correlation analysis with the content of hormone there is no significantly positive correlation.