Studies On Somatal Characteristic, Photosynthesis Characteristic And Sucrose Metabolic Of Rice Leaf In The Filial Generation From Indica And Japonica

Stomata are the pores on leaf surfaces controlling gas exchanges, mainly CO2 and water vapor, between the atmosphere and plants, and thus regulate carbon and water cycles in various ecosystems. Stomatal traits of indica and japonica rice exist obvious differences. Large variation in their hybrid strains and significant heterobeltiosis, make full use of advantages between subspecies characteristics has become one of the main breeding theme. This article selects 187 recombinant inbred lines in F13 as the test materials, which was obtained by typical indicia Qishanzhan and typical japonica Akihikari. This study investigated the flag leaf characters and stomatal aperture size and shape, and stomatal distribution pattern, and their relationships with the leaf gas exchange rates of rice leaves through a field experiment. Then, we selected the different stomatal density (high, medium and low) strain for materials. To determine the index of the following:(1) comparative study the stomatal density and Rubisco enzyme activity on the photosynthetic characteristics of different rice at the heading stage (2) different stomatal density daily variation of rice leaf photosynthesis and chlorophyll fluorescence characteristics (3) Components of sugar content, sucrose metabolism related enzyme activity and sucrose transporters of flag leaf. Our results were showed as follows.1. Indica japonica hybrids exist widely in leaf traits and stomatal traits variation. Leaf length, width, area and specific leaf weight, stomatal density, length and width were close to normal continuous variation, and there was obvious transgressive inheritance phenomenon. The results suggested that these leaf traits and stomatal traits were controlled by polygene quantitative traits. Correlation analysis showed that the leaf length, leaf width and extremely significant positive correlation between leaf area, leaf length, leaf width, and specific leaf weight correlation, which did not reach the significant level. In addition to the leaf length and the stomata length was significantly positively related, had no significant correlation between leaf traits and stomatal traits. Stomata density and stomata length and width of stomatal significantly or significantly negative correlation, stomatal length and width of stomatal was significantly positively related.2. According to the stomatal density test materials can be divided into high (HSD:859+27/ mm2), medium (MSD:718+17/mm2) and low (LSD:619+19/mm2) three types of stomatal length transverse (leaf margin to the main vein) or vertical (leaf base to tip) the change law of roughly LSD> MSD> HSD. There was no significant difference at the same position among 3 types rice. Lateral leaf to leaf area were similar, central longitudinal tip was greater than the base. Longitudinal change rule roughly 2/5 leaf> leaf middle>4/51eaf>leaf base>leaf tip. Blade 2/5 parts was no significant difference to leaf central,4/5 part was slightly lower than 2/5 place and central leaf, leaf base close to tip. Leaf 2/5, leaf central and 4/5 place especially the stomatal density of the two are characterized by HSD> MSD> LSD, determined the difference between the type of stomata density. Stomatal types of leaf base and leaf tip was relatively smaller.3. We investigated photosynthetic light, CO2 response and Rubisco enzyme activity. The results showed that maximum photosynthetic rate of the optical response was HSD, reached 24.6μmol·m-2·s-1, respectively higher than MSD, LSD by 4.3% and 19.6%. The maximum photosynthetic rate of CO2 response was HSD, reached 30.8μmol·m-2·s-1, respectively,4.6% and 9.5% higher than MSD, LSD. In addition, Rubisco enzyme activity of rice with different stomatal density was consistent with stomatal density, which was performed very significant positive correlation (r= 0.912, P<0.01). With the increase of stomatal density, light saturation point, apparent quantum efficiency, light compensation point and dark respiration rate decreased, which indicated that high stomatal density was beneficial to improve the utilization efficiency of light energy and CO2.4. Daily change rule of photosynthesis and chlorophyll fluorescence were investigated in 3 kinds of stomatal density rice. Results showed that the net photosynthetic rate (Pn) of rice materials were bimodal curve asymmetrical, the daily change occurred the first peak from 9:00 to 10:00 and the second peak from 14:00 to 15:00. There was an obvious "photosynthetic lunch break", which was mainly caused by stomatal factors. The sequence of Pn in 3 kinds of rice were HSD>MSD>LSD. Pn and environmental factors of PAR and Ta were significantly positively related to respectively and were positively correlated, and photosynthetic parameters of Tr and Gs were significantly positively related. Initial fluorescence (Fo) showed an unimodal curve with a peak in the afternoon and the change rule was HSD> MSD> LSD. The diurnal variation of Maximum light energy conversion efficiency (Fv/Fm) in PS II was opposite. Compared with low stomatal density rice, the rice with a higher stomatal density has a certain photosynthetic advantage under not affected by high light and temperature stress, But in the light under high temperature stress, photoinhibition occurred and the heavier the recovery process was quite long, it could be a strong light damage caused by high temperature caused by the heavier.5.Sugar content and enzyme activity in sucrose metabolism of flag leaf were determined. Results showed that the content of sucrose and sucrose phosphate synthase (SPS) in rice leaves were significantly positively correlated with stomata density (P<0.01), and activities of sucrose synthase (SS) was positively correlated with stomata density (P<0.05). Rubisco activity、net photosynthetic rate、sucrose content、sucrose phosphate synthase and sucrose synthase in rice leaves with high stomata density were higher than that in rice leaves with low stomata density, in addition, sucrose content was significantly positively correlated with the sucrose phosphate synthase (P<0.01) and sucrose synthase activity (P<0.05), while negatively correlated with acid invertase (AI) and neutral invertase (NI). This research shows that stomata density increased with the increase of rice leaf photosynthetic efficiency, promoted the sucrose accumulation and sucrose metabolism enzymes (SPS and SS) activity increased, which was in favor of more photosynthate like sucrose transport to the grain.