| Diurnal and seasonal variation of photosynthesis physiology targets of tetraploid and diploid Eucommia ulmoides were studied comparatively with Li-6400 portable photosynthesis analyzer system produced from May of 2011 to October of 2011. The response of light、CO2 concentration of photosynthesis、the chlorophyll fluorescence characteristic were studied. Knowing about the difference of Photosynthetic efficiency, in order to provide scientific bases for choosing the excellent varieties and high efficient cultivation, and to provide reference for improving photosynthetic capacity and productivity. The results were as follows:1.Diurnal variation of Pn of tetraploid and diploid Eucommia ulmoides present single and double curve. When it presents double curve from May to August, the noon rest of Pn may occurred; It presents single curve from September to October. There are significant differences among tetraploid and diploid, tetraploid are higher than the diploid. The overall change trend is: tetraploid1>tetraploid2>tetraploid3>tetraploid4>diploid.2.The differences of Pn among tetraploid and diploid Eucommia ulmoides in different months have significant differences, the overall change trend is: June>August>May>July>September>October. The highest value appears in June, and the lowest value in the October.3.Seasonal variation of transpiration and Photosynthetic rate are almost alike tendency of tetraploid and diploid Eucommia ulmoides, the order of the average transpiration rate from May to October: June>July>August>May>September>October.4.The LSP of tetraploid and diploid Eucommia ulmoides is between 1216.7μmol.m-2.s-1 and 1272.2μmol.m-2.s-1, The LSP of tetraploid is higher than diploid. The LCP of tetraploid is between 10.6μmol.m-2.s-1 and 37.2μmol.m-2.s-1. The Pmax of tetraploid and diploid Eucommia ulmoides is between 12.1 and 14.9μmol.m-2.s-1, tetraploid are larger than diploid in June. Theαof tetraploid and diploid is between 0.03 and 0.05, tetraploid are higher than the diploid. The order of the photosynthetic capacity: tetraploid1>tetraploid4>tetraploid2>tetraploid3>diploid.5.The CSP of tetraploid and diploid Eucommia ulmoides is between 1340 and 1410μmol.mol-1, The CSP of tetraploid is higher than diploid. the CCP of tetraploid and diploid is between 70 from 120μmol.mol-1. The CCP of tetraploid is lower than diploid.The CE of tetraploid and diploid is between 0.03 and 0.06, The CE of tetraploid is higher than the diploid.6.The Fm of tetraploid and diploid Eucommia ulmoides showed a consistent change with Fv/Fm. The Fv/Fm of tetraploid is higher than the diploid. Not only can absorb more light energy, but also have high activity and efficiency of light energy conversion. Eucommia ulmoides diploid shows relatively weak photosynthetic activity. ETR, qP and qN of tetraploid were generally higher than diploid, which showed that tetraploid can minimize the degree of photoinhibtion through increasing sunshine dissipated and be more adapted to the environment than diploid.7.The curve of seasonal variation of Chla、Chlb and Chlt are similar, which is different from Chla/b, the change of curve of seasonal variation of Chla/b is stable. the order of the variation Chlt from May to October: tetraploid1>tetraploid2>tetraploid3> tetraploid4>diploid. The highest value appears in August, and the lowest value in the October. The Chla/b of tetraploid is higher than the diploid.8.The tetraploid and diploid of Eucommia ulmoides by principal component analysis, the results show that the order of Eucommia ulmoides tetraploid and diploid in photosynthetic aspects of the comprehensive factor score: tetraploid1>tetraploid2> tetraploid4>tetraploid3>diploid. |
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