Effects Of Exogenous Hormones On Photosynthesis Characteristics And Yield Component In Rapeseed

Photosynthesis is the basis of plant biological science. It is also the eventually goal to increase crop yield. Plant hormones have the effects to the plant development and plant adaptability to the environment. Those achievements of plant hormones research are the important theory source of genetic improvement and plant breeding;Moreover they also create the revolutionary changes to production practice. Photosynthetic characteristics and effects of exogenous hormones ABA, BR and KT to photosynthesis organs were investigated in the key growth stage of rapeseed in this thesis.Results showed:1. Different concerntration of two hormones were sprayed in initial blooming and silique stage, photosynthetic rate of short petiole, non-petiole leaves and silique was mensurated, and the yield components were analysised. The photosynthetic declination of above two leaves was consistent, especially the two treatment ABA 0.076μmol/Land BR 1μmol/L had the significant effects to Pn improving and APD maintenance; APD of silique was postponed by 2μmol/L BR treatment virtually; The rest ABA 0.076μmol/L and BR 1μmol/L had not obviously effects on silique. The highest concerntration ABA150μmol/L hastened the silique senescence. Further more plant height and branches position of the economic characteristics, were influenced by the hormones easily, the same as the number of grain number per silique.2. 0.076μmol/L ABA, 1μmol/L BR and 1μmol/L KT had different effects to the long petiole leaves Pn after treatments in seedling stage. Generally, KT could delay the Chlorophyll degradation and increase Pn, whereas the effect could not keep further of seedling stage. But BR had the opposite effect.So BR could maintain Chlorophyll stabilization and prolong the APD. After calculating, KT protracted RSP about 8 to 10 days, ABA 5 to 10 days and BR 3 to 4 days comparing to the control group. Meanwhile RuBPCase activity was studied. The results illustrated RuBPCase activity increased later than Pn, but both had the same trend. The conclusion showed all these hormones could prolong the RSP in different degree, so as to increase the photosynthesis time.3. The results indicated light saturation points of rapeseed leaf was 950μmol·m-2·s-1, apparent quantum efficiency was 0.044. It could be estimated that respiration rate, CO₂ saturation point and CO₂ compensation point were 3.45μmol·m^-2·s^-1, 1100μmol·m^-2·s^-1 and 48.439μmol·mol-1 respectively. After that, the same parameters above were mensurated under different treatments, some changes happened like that LSP was increased but also RD and CSP decreased at the same time. Among the fluorescence parameters the maximal photochemical efficiency of PSâ…¡(Fv/Fm) of control was lowest, three treatments had influence to fluorescence parameters. It indicated that low temperature affected the photosynthesis ability of rapeseed. Conversion efficiency and primary capture efficiency of light energy of PSâ…¡were accelerated under treatments. Quantum yield being used to Photosynthetic electron transport of PSâ…¡increased, too. Non-ring electronic transmission rate became fast after treatments.