| This experiment had used Li-6400 portable photosynthesis system to determine the light quality of leaves in different planted way and senescent ginkgo leaves. Under artificial gradient illumination, using the scan electron microscope and the energy spectrum analysis determined the movement of stomata and the elements content of guard cells and subsidiary cells of ginkgo leaf. And using TENCAI-12-type transmission electronic microscope studied the ultrastructure of senescent ginkgo leaves and the leaves under different light. The results showed that:1. The average net photosynthetic rate of natural ginkgo leaves in different floor was smaller than shortenized and densely planted ginkgo's, but the CV of it was changed bigger than that; The light compensation point of natural planted ginkgo leaves in the top,middle and bottom-level were 40.39,48.13 and 27.44μmol·m-2·s-1,The light compensation point of natural planted ginkgo leaves in different floor appears within range about 600~800μmol·m-2·s-1.2. The K concentration difference between guard cells and subsidiary cells of ginkgo leaf showed significant regular changes, correlative equation was Y=3E-10X3-1E-06X2+0.0017X+1.334.53,R2=0.8129, showed the extremely significant curvilinear correlation. The K+ concentration difference is the biggest when illumination intensity at 800μmol·m-2·s-1,under excessively strong or excessively weak illumination intensity, the K concentration difference between guard cells and subsidiary cells is comparative small; Fitting the relation between stomatal open state and the illumination intensity, correlative equationY=6E-10X3-3E-06X2+0.0037X+3.7438, R2=0.9151, showed the extremely significant curvilinear correlation;The K content had direct function to the stomatal open state, The S and Cl and the negative function to the stomatal open state, but they had big function to the stomatal open state get across K; The element contents of guard cells were higher than subsidiary cells were K,Ca,S,Mn,Fe,Cl,Cu, the element contents of the subsidiary cells were higher than the guard cell were O,Mg,P; The observation through transmission electron microscope showed that there was cutin liplike protuberance at the peripheric subsidiary cells of ginkgo leaves, papillate, invaginate of the stoma.3. The chl a content and the chl b content showed a significant downward trend, carotenoid content showed a up trend; The net photosynthetic rate and Ls showed a significant downward trend, bue the Ci showed a up trend. Account according to ginkgo grew up in our college, the result showed that Pn get 0 on Nov.16th,2007, and 880.21g CO2 would be released every ginkgo from Nov.16th to Nov.27th; The results indicated that the chloroplasts variation was significant during senescence of ginkgo: The chloroplasts'shape changed form oblong to sphere, and the membrane envelope of chloroplast broke. The grana lamella and the stroma lamella of chloroplast arranged disorderly and blurring finally. The plastoglobulus increased. The cristaes in the mitochondria and the endoplasmic reticulum decreased.4. There had no chloroplast exist under dark treatment. And the plastid in etiolated seedlings developed into etioplast. And the obvious character of the etioplast is there had the prolamellar body exist. Use the white,red and blue light treatment to the etiolated seedlings, found that chloroplast had formed under all this light treatment. Research on microstructure changes of etiolated ginkgo leaves under red light treatment showed that chloroplast had formed and there had some stroma lamella in it. But research on microstructure changes of etiolated ginkgo leaves under white and blue light treatment showed that chloroplast had formed and there had some stroma lamella in it. And the grana lamella piled up. the grana lamella piled up under the white light treatment is higher than the blue light's... |
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