Effect of fertilizer source （mineral fertilizer or organic manure） on photosynthetic pigments leaves content of four brassica vegetables （Pak choi, Kohlrabi, Cauliflower and Cabbage） was tested. Among treatments, ...Effect of fertilizer source （mineral fertilizer or organic manure） on photosynthetic pigments leaves content of four brassica vegetables （Pak choi, Kohlrabi, Cauliflower and Cabbage） was tested. Among treatments, cauliflower fertilized with chicken manure had the highest content of chlorophyll a and b （10.08 and 9.37 μm·g^-1）, while, pak choi had the lowest values （2.00 and 2.44 μm·g^-1） in non-fertilized plants. These differences in chlorophyll a and b content may have a great impact on photosynthetic rate and activity. Total carotenoids and total xanthophylls （lutein, zeaxanthin, antheraxanthin and violaxanthin） were the highest in cauliflower while the lowest was in pakchoi, β-carotene, on the other hand, was the highest percentage of total carotenoids （65.7%） in pak choi while Kohlrabi had the lowest percent （57.4%）. This high percentage offl-carotene of total carotenoids may compensate for lower content of chlorophylls and assist for efficient light harvesting process. Lutein showed to be the major components of xanthophyll pigments brassica vegetables and ranged from 0.462μm·g^-1 in cabbage to 0.626μm·g^-1 in kohlrabi but not differed significantly which may refer to genetically controlled. However, lutein, antheraxanthin and zeaxanthin content were increased significantly by the application of chicken manure regardless ofbrassica vegetable type. Violaxanthin was only detected in pak choi and not affected by fertilizer source. It can be concluding from the increasing contents of total xanthophylls pigments that may increase photosynthetic efficiency through non-photochemical quenching process.展开更多
The purpose of the present studies was analysis of the age induced changes in photochemical efficiency and xanthophyils cycle pigments of the primary cabbage （Brassica oleracea L. cv. Capitata f. alba） leaves. Photo...The purpose of the present studies was analysis of the age induced changes in photochemical efficiency and xanthophyils cycle pigments of the primary cabbage （Brassica oleracea L. cv. Capitata f. alba） leaves. Photochemical efficiency of photosystem Ⅱ （PS Ⅱ） was studied by a pulse amplitude modulated chlorophyll fluorescence apparatus, chlorophyll concentration was analysis spectrophotometrically and xanthophyll cycle pigments were estimated by high-pressure liquid chromatography （HPLC）. Leaf senescence was accompanied with a decrease both in chlorophylls concentration, the photochemical efficiency and rate constant for PS Ⅱ photochemistry whereas non-photochemical parameters increased. Excitation pressure （1-qP） which is a measure of relative lumen acidification increased by 1.2x in aging leaves. The maximum quantum yield of PS Ⅱ showed no significant change. The level of de-epoxidised xanthophylls increased but the concentration of mono- and di-epoxy xanthophylls decreased in aging leaves. A linear relationship between the excitation pressure and the depoxidation state of the xanthophyll cycle pigments and lutein, during the onset of senescence suggests that excitation pressure can be used as a sensor for monitoring the onset of senescence as well for the de-epoxidation state of the xanthophylls responsible for non-photochemical quenching in stressed leaves.展开更多
文摘Effect of fertilizer source （mineral fertilizer or organic manure） on photosynthetic pigments leaves content of four brassica vegetables （Pak choi, Kohlrabi, Cauliflower and Cabbage） was tested. Among treatments, cauliflower fertilized with chicken manure had the highest content of chlorophyll a and b （10.08 and 9.37 μm·g^-1）, while, pak choi had the lowest values （2.00 and 2.44 μm·g^-1） in non-fertilized plants. These differences in chlorophyll a and b content may have a great impact on photosynthetic rate and activity. Total carotenoids and total xanthophylls （lutein, zeaxanthin, antheraxanthin and violaxanthin） were the highest in cauliflower while the lowest was in pakchoi, β-carotene, on the other hand, was the highest percentage of total carotenoids （65.7%） in pak choi while Kohlrabi had the lowest percent （57.4%）. This high percentage offl-carotene of total carotenoids may compensate for lower content of chlorophylls and assist for efficient light harvesting process. Lutein showed to be the major components of xanthophyll pigments brassica vegetables and ranged from 0.462μm·g^-1 in cabbage to 0.626μm·g^-1 in kohlrabi but not differed significantly which may refer to genetically controlled. However, lutein, antheraxanthin and zeaxanthin content were increased significantly by the application of chicken manure regardless ofbrassica vegetable type. Violaxanthin was only detected in pak choi and not affected by fertilizer source. It can be concluding from the increasing contents of total xanthophylls pigments that may increase photosynthetic efficiency through non-photochemical quenching process.
文摘The purpose of the present studies was analysis of the age induced changes in photochemical efficiency and xanthophyils cycle pigments of the primary cabbage （Brassica oleracea L. cv. Capitata f. alba） leaves. Photochemical efficiency of photosystem Ⅱ （PS Ⅱ） was studied by a pulse amplitude modulated chlorophyll fluorescence apparatus, chlorophyll concentration was analysis spectrophotometrically and xanthophyll cycle pigments were estimated by high-pressure liquid chromatography （HPLC）. Leaf senescence was accompanied with a decrease both in chlorophylls concentration, the photochemical efficiency and rate constant for PS Ⅱ photochemistry whereas non-photochemical parameters increased. Excitation pressure （1-qP） which is a measure of relative lumen acidification increased by 1.2x in aging leaves. The maximum quantum yield of PS Ⅱ showed no significant change. The level of de-epoxidised xanthophylls increased but the concentration of mono- and di-epoxy xanthophylls decreased in aging leaves. A linear relationship between the excitation pressure and the depoxidation state of the xanthophyll cycle pigments and lutein, during the onset of senescence suggests that excitation pressure can be used as a sensor for monitoring the onset of senescence as well for the de-epoxidation state of the xanthophylls responsible for non-photochemical quenching in stressed leaves.
