Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular in...Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular intervals there after within 15 d. Photoinhibition occurred in shade-grown cotton leaves immediately after exposed to full sunlight. The chlorophyll fluorescence parameter F-v/F-m and PhiPS II, which reflect the efficiency of PS II,obviously decreased in shade-grown leaves, much lower than that of the full sunlight-grown leaves. On the contrary, F-o value was sharply increased. Neither of these parameters could completely recover till next morning. The photoinhibition was chronic and continued for about 4 d, while the F-v/F-m and the net photosynthetic rate ( P-n) continued to decline, then began to increase gradually 6 d later and turned stable after 10 - 12 d, appearing as an acclimation phenomenon. However, the final value of F-v/F-m and P-n did not reach the level as in those leaves grown in the full sunlight ever before. The final P-n was higher by 60% than that before exposure, but lower for more than 40% than that of the full sunlight-grown leaves. The most notable response of chloroplast pigment composition was a pronounced increase in the pool size of carotenoids in xanthophyll cycle over a period of 3 d. The results indicated that when shade-grown cotton seedlings were suddenly transferred to the full sunlight, the decline of F-v/F-m and P-n might associate with the damage of the PS II reaction center. During the light acclimation, photoprotective mechanisms such as the xanthophyll cycle-dependent energy dissipation were increased, so that photodamage in leaves transferred from low to high light might be reduced.展开更多
In midday ginkgo ( Ginkgo biloba L.) leaves have to bear photon flux density over 1400 μmol·m -2 ·s -1 in combination with high temperatures around 35 ℃ at natural habitat. They show typical mi...In midday ginkgo ( Ginkgo biloba L.) leaves have to bear photon flux density over 1400 μmol·m -2 ·s -1 in combination with high temperatures around 35 ℃ at natural habitat. They show typical midday depression of stomatal conductance and of CO 2 assimilation rate. The zeaxanthin changes with light intensity during the day. The influence of the combination of strong light and temperature on photoinhibition was also examined in the laboratory. A low CO 2 internal conductance (31 mmol·m -2 ·s -1 ) was found in ginkgo leaves, which had been exposed to excessive light at temperature between 15 ℃ and 35 ℃ with reduced CO 2 (80 μL·L -1 ) or oxygen (2%) for 2 h, causing a low CO 2 concentration at the carboxylation site and a high proportion of photorespiration. The ratio of electron transport to CO 2 fixation was rather high in ginkgo (16 e -/CO 2 at 25 ℃) as compared with other plants. It increased with temperature also in 2% O 2 which could not be explained solely as due to change of photorespiration. The reduction of oxygen in 340 or 80 μL·L -1 CO 2 had no effect on the extent of photoinhibition at all temperatures, which indicated that electron flow caused by photorespiration in excess light was negligible in protective effect in ginkgo leaves. However, a decreased CO 2 concentration increased photoinhibition, especially at high temperature. It is concluded that the dissipation of excessive excitation energy in the PSⅡ antennae through the xanthophyll cycle may be the major protective mechanism to preventing from the deteriorated effects of strong light in ginkgo leaves.展开更多
Relationships between fluorescence parameters and membrane lipid peroxidation in leaves of indica and japonica rice (Oryza sativa L.) during later growth stage were studied under chilling temperature and strong light ...Relationships between fluorescence parameters and membrane lipid peroxidation in leaves of indica and japonica rice (Oryza sativa L.) during later growth stage were studied under chilling temperature and strong light stress conditions. Results showed that D1 protein contents of PSⅡ in photosynthetic apparatus dropped, the generation of antheraxanthin (A) and zeaxanthin (Z) of xanthophyll cycle were inhibited partly, PSⅡ photochemical efficiency (F v/F m)and non-photochemical quenching (q N) were also decreased obviously. In addition, endogenous active oxygen scavenger—superoxide dismutase (SOD) reduced, superoxide anion radical (O -· 2) and malondialdehyde (MDA) accumulated, as a result, photooxidation of leaves occurred under chilling temperature and strong light stress conditions. Obvious differences in the changes of the above mentioned physiological parameters between indica and japonica rice were observed. Experiments in leaves treated with inhibitors under chilling temperature and strong light conditions showed that indica rice was more sensitive to chilling temperature with strong light and subjected to photooxidation more than japonica rice. Notable positive correlation between D1 protein contents and F v/F m or (A+Z)/(A+Z+V), and a marked negative correlation between F v/F m and MDA contents were obtained by regression analysis in indica and japonica rice during chilling temperature and strong light conditions. According to the facts mentioned above, it was inferred that PSⅡ photochemical efficiency(F v/F m) was the key index to forecast for the prediction of photooxidation under stress circumstances and the physiological basis were the synthetic capacity of D1 protein and the protection of xanthophyll cycle.展开更多
The mechanism of high yield of winter wheat in the field at late growth period was investigated by measuring the photosynthetic characteristics of photosystem Ⅱ （PSⅡ） and xanthophylls cycle, which could provide ph...The mechanism of high yield of winter wheat in the field at late growth period was investigated by measuring the photosynthetic characteristics of photosystem Ⅱ （PSⅡ） and xanthophylls cycle, which could provide physiological reference for breeding. Weimai 8 （W8）, a super high yield cultivar, and Lumai 14 （L14）, a control cultivar were object. The photosynthetic rate （Pn）, parameters of chlorophyll fluorescence and chlorophyll content were measured. The Pn, maximum photochemical efficiency of PSII （Fv/Fm）, quantum yield of PSII electron transport （ΦPSⅡ）, efficiency of excitation energy capture by open PSII reaction centers （Fv＇/Fm＇）, and photochemical quenching coefficient （qP） were higher in Weimai 8 compared to that in Lumai 14, a commercial high yield cultivar. Furthermore, Weirnai 8 showed a lower non- photochemical quenching coefficient and a lower de-epoxidized ratio of the xanthophyll cycle pigments than of Lumai 14 at late growth period. At mature stage, chlorophyll content of different leaves decreased both in Weimai 8 and Lumai 14. Chlorophyll content in flag, second and third leaf from the top of plant decreased more in Lumai 14 than in Weimai 8. These results suggested that Weimai 8 had more antenna pigments to absorb light energy, and had higher photosynthetic capability and photochemical efficiency of PSⅡ. The yield of Weimai 8 was also higher than that of Lumai 14.展开更多
应用高效液相色谱法分析海南113种热带植物的叶黄素和β-胡萝卜素含量。结果表明:叶黄素含量>1000 m g/kg者44种,500 m g/kg<叶黄素含量<1000 m g/kg者42种,200 m g/kg<叶黄素含量<500 m g/kg者21种、在200 m g/kg以下者...应用高效液相色谱法分析海南113种热带植物的叶黄素和β-胡萝卜素含量。结果表明:叶黄素含量>1000 m g/kg者44种,500 m g/kg<叶黄素含量<1000 m g/kg者42种,200 m g/kg<叶黄素含量<500 m g/kg者21种、在200 m g/kg以下者6种;β-胡萝卜素含量>50 g/kg者33种、20 g/kg<β-胡萝卜素含量<50 g/kg者65种、小于20 g/kg者15种;研究结果对热带植物类胡萝卜素资源综合开发与利用者有一定参考价值。展开更多
文摘以万寿菊花粉为原料,探明超声波强化石油醚提取叶黄素的工艺条件。确定适合提取用原料的粒度后,采用正交试验研究料液比、超声波功率、超声作用时间对提取率的影响。结果显示,较理想的提取条件为:料液比1∶25[质量(g)体积(m l)比]、超声波功率500 W、超声波作用时间30 m in,此条件下叶黄素的萃取率可达97%以上。
文摘Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular intervals there after within 15 d. Photoinhibition occurred in shade-grown cotton leaves immediately after exposed to full sunlight. The chlorophyll fluorescence parameter F-v/F-m and PhiPS II, which reflect the efficiency of PS II,obviously decreased in shade-grown leaves, much lower than that of the full sunlight-grown leaves. On the contrary, F-o value was sharply increased. Neither of these parameters could completely recover till next morning. The photoinhibition was chronic and continued for about 4 d, while the F-v/F-m and the net photosynthetic rate ( P-n) continued to decline, then began to increase gradually 6 d later and turned stable after 10 - 12 d, appearing as an acclimation phenomenon. However, the final value of F-v/F-m and P-n did not reach the level as in those leaves grown in the full sunlight ever before. The final P-n was higher by 60% than that before exposure, but lower for more than 40% than that of the full sunlight-grown leaves. The most notable response of chloroplast pigment composition was a pronounced increase in the pool size of carotenoids in xanthophyll cycle over a period of 3 d. The results indicated that when shade-grown cotton seedlings were suddenly transferred to the full sunlight, the decline of F-v/F-m and P-n might associate with the damage of the PS II reaction center. During the light acclimation, photoprotective mechanisms such as the xanthophyll cycle-dependent energy dissipation were increased, so that photodamage in leaves transferred from low to high light might be reduced.
文摘In midday ginkgo ( Ginkgo biloba L.) leaves have to bear photon flux density over 1400 μmol·m -2 ·s -1 in combination with high temperatures around 35 ℃ at natural habitat. They show typical midday depression of stomatal conductance and of CO 2 assimilation rate. The zeaxanthin changes with light intensity during the day. The influence of the combination of strong light and temperature on photoinhibition was also examined in the laboratory. A low CO 2 internal conductance (31 mmol·m -2 ·s -1 ) was found in ginkgo leaves, which had been exposed to excessive light at temperature between 15 ℃ and 35 ℃ with reduced CO 2 (80 μL·L -1 ) or oxygen (2%) for 2 h, causing a low CO 2 concentration at the carboxylation site and a high proportion of photorespiration. The ratio of electron transport to CO 2 fixation was rather high in ginkgo (16 e -/CO 2 at 25 ℃) as compared with other plants. It increased with temperature also in 2% O 2 which could not be explained solely as due to change of photorespiration. The reduction of oxygen in 340 or 80 μL·L -1 CO 2 had no effect on the extent of photoinhibition at all temperatures, which indicated that electron flow caused by photorespiration in excess light was negligible in protective effect in ginkgo leaves. However, a decreased CO 2 concentration increased photoinhibition, especially at high temperature. It is concluded that the dissipation of excessive excitation energy in the PSⅡ antennae through the xanthophyll cycle may be the major protective mechanism to preventing from the deteriorated effects of strong light in ginkgo leaves.
文摘Relationships between fluorescence parameters and membrane lipid peroxidation in leaves of indica and japonica rice (Oryza sativa L.) during later growth stage were studied under chilling temperature and strong light stress conditions. Results showed that D1 protein contents of PSⅡ in photosynthetic apparatus dropped, the generation of antheraxanthin (A) and zeaxanthin (Z) of xanthophyll cycle were inhibited partly, PSⅡ photochemical efficiency (F v/F m)and non-photochemical quenching (q N) were also decreased obviously. In addition, endogenous active oxygen scavenger—superoxide dismutase (SOD) reduced, superoxide anion radical (O -· 2) and malondialdehyde (MDA) accumulated, as a result, photooxidation of leaves occurred under chilling temperature and strong light stress conditions. Obvious differences in the changes of the above mentioned physiological parameters between indica and japonica rice were observed. Experiments in leaves treated with inhibitors under chilling temperature and strong light conditions showed that indica rice was more sensitive to chilling temperature with strong light and subjected to photooxidation more than japonica rice. Notable positive correlation between D1 protein contents and F v/F m or (A+Z)/(A+Z+V), and a marked negative correlation between F v/F m and MDA contents were obtained by regression analysis in indica and japonica rice during chilling temperature and strong light conditions. According to the facts mentioned above, it was inferred that PSⅡ photochemical efficiency(F v/F m) was the key index to forecast for the prediction of photooxidation under stress circumstances and the physiological basis were the synthetic capacity of D1 protein and the protection of xanthophyll cycle.
基金supported by the Key Project of Shandong Agriculture: Breeding Technology Research of Super Wheat for High Yield and High Qulity, China([2006]6), the Opening Foundation of the State Key Laboratory of Crop Biology, China (2008KF03)the Postdoctor Innovative Foundation of Shandong Province, China (200802009)+2 种基金the National Basic Re-search of China (973 Program, 2009CB118500)the National Natural Science Foundation of China(30871458)the Program for Changjiang Scholarsand Innovative Research Team in University, China(IRT0635)
文摘The mechanism of high yield of winter wheat in the field at late growth period was investigated by measuring the photosynthetic characteristics of photosystem Ⅱ （PSⅡ） and xanthophylls cycle, which could provide physiological reference for breeding. Weimai 8 （W8）, a super high yield cultivar, and Lumai 14 （L14）, a control cultivar were object. The photosynthetic rate （Pn）, parameters of chlorophyll fluorescence and chlorophyll content were measured. The Pn, maximum photochemical efficiency of PSII （Fv/Fm）, quantum yield of PSII electron transport （ΦPSⅡ）, efficiency of excitation energy capture by open PSII reaction centers （Fv＇/Fm＇）, and photochemical quenching coefficient （qP） were higher in Weimai 8 compared to that in Lumai 14, a commercial high yield cultivar. Furthermore, Weirnai 8 showed a lower non- photochemical quenching coefficient and a lower de-epoxidized ratio of the xanthophyll cycle pigments than of Lumai 14 at late growth period. At mature stage, chlorophyll content of different leaves decreased both in Weimai 8 and Lumai 14. Chlorophyll content in flag, second and third leaf from the top of plant decreased more in Lumai 14 than in Weimai 8. These results suggested that Weimai 8 had more antenna pigments to absorb light energy, and had higher photosynthetic capability and photochemical efficiency of PSⅡ. The yield of Weimai 8 was also higher than that of Lumai 14.
文摘应用高效液相色谱法分析海南113种热带植物的叶黄素和β-胡萝卜素含量。结果表明:叶黄素含量>1000 m g/kg者44种,500 m g/kg<叶黄素含量<1000 m g/kg者42种,200 m g/kg<叶黄素含量<500 m g/kg者21种、在200 m g/kg以下者6种;β-胡萝卜素含量>50 g/kg者33种、20 g/kg<β-胡萝卜素含量<50 g/kg者65种、小于20 g/kg者15种;研究结果对热带植物类胡萝卜素资源综合开发与利用者有一定参考价值。
