Study on Characteristics of Conversion of Light Energy in Photosynthetic Membrane from Top Second Leaf and Top Third Leaf of Liangyoupeijiu during Heading Stage
XIANG Xiu-lan et al (College of Life Science,Nanjing Normal University,Nanjing,Jiangsu 210046)
[Objective] Based on the level of photosynthetic membrane,characteristics of conversion of light energy of top second leaf and top third leaf of Liangyoupeijiu were studied to explore the function of the top second leaf and top third leaf physiological changes in the heading stage,to reveal the photosynthetic function of different aging leaves.[Method] Taking Liangyoupeijiu as material,content of chlorophyll,carotenoid,soluble protein,total soluble sugar and electron transfer activity of PSⅠ and PSⅡ,the absorption spectra of thylakoid membrane at room temperature and emission spectra of thylakoid membrane at room temperature of the top second leaf and the top third leaf were determined. [Result] The contents of chlorophyll and carotenoid of the top second leaf and the top third leaf decreased with the extension of time sampling.Both the soluble protein content and total soluble sugar content decreased,but the rate of declining of the top third leaf was bigger than that of the second leaf.PSⅠ electron transfer activity of two function leaves were constantly declining,and their PSⅡ electron transfer activity declined after rising.Absorption spectra of thylakoid membrane at room temperature increased at the early time,and then decreased,while the emission spectra at room temperature descended firstly and then increased.[Conclusion] The physiological changes of the top third leaf in heading were more evident than those of the top second leaf.The photosynthetic function of the top third leaf was weaker than that of the top second leaf. The aging rate of top third leaf was faster than that of the top second leaf.