The protective role of xanthophyll cycle in resurrection angiosperm Boea hygrometrica (Bunge) R.Br. was investigated by analysis of the changes of chlorophyll fluorescence and xanthophyll cycle components in response ...The protective role of xanthophyll cycle in resurrection angiosperm Boea hygrometrica (Bunge) R.Br. was investigated by analysis of the changes of chlorophyll fluorescence and xanthophyll cycle components in response to dehydration and rehydration in detached leaves under very weak light condition (3 mumol photons.m(-2).s(-1)) and in the dark. With declines in the values of PSII photochemical efficiency (Fv/Fm), PSII actual quantum yield (Phi(PSII)), photochemical quenching (qP) and non-photochemical quenching (NPQ) during dehydration, zeaxanthin significantly increased in control Boea leaves under very weak light condition, while no zeaxanthin accumulation was detected in Boea leaves treated with dithiothreitol (DTT) and Boea leaves in the dark, and after 3 d rehydration, the parameters Fv/Fm, Phi(PSII), qP and NPQ showed full recovery in control Boea leaves under very weak light condition, but the parameters only underwent partial recovery in Boea leaves treated with DTT and Boea leaves in the dark, suggesting that the recovery of photosystem II (PSII) photochemical activities in Boea leaves was obviously affected by treatments with DTT and darkness, therefore, zeaxanthin may play an important protective role in desiccated Boea leaves even under very weak light conditions.展开更多
Resurrection plants which are able to quickly reactivate after falling into a period of anabiosis caused by dehydration have been very rare among angiosperms, especially among dicotyledons whose chlorophyll content an...Resurrection plants which are able to quickly reactivate after falling into a period of anabiosis caused by dehydration have been very rare among angiosperms, especially among dicotyledons whose chlorophyll content and chloroplast structure little changed in the course of desiccation, therefore has been called homoiochlorophyllous desiccation-tolerant plants (HDTs). Another type of resurrection angiosperms that lost its chlorophyll dining desiccation is called poikilochlorophyllous desiccation-tolerant plants (PDTs). HDTs have been received more attention because of simplicity of protection mechanism which is much easy to the study and utilization of the desiccation tolerance of resurrection angiosperms. Recent advances in studies of photosynthesis of resurrection angiosperms indicate that photochemical activities are sensitive indicators for the study of physiological state of resurrection angiosperms during desiccation and rehydration. Photochemical activities of resurrection angiosperms are inhibited with loss of water similar to those of general plants, however, the magic thing is that they could reactivate rapidly during rehydration even losing more than 95% water. Up-regulations in xanthophyll cycle and antioxidative systems as well as preservation in integrity and stability of photosynthetic membranes during desiccation may be very important to desiccation tolerance of resurrection angiosperms. The fact that phosphate treatment in rehydration stage also strongly influences resurrection indicated importance of studies on rehydration stages of resurrection angiosperms.展开更多
The resurrection plants Ramonda serbica and Ramonda nathaliae are the physiological model plant and endemic species from Balkan Peninsula. Study was carried out to assess the impact of different populations on photosy...The resurrection plants Ramonda serbica and Ramonda nathaliae are the physiological model plant and endemic species from Balkan Peninsula. Study was carried out to assess the impact of different populations on photosynthetic pigment contents and their effect on physiological activity of these species. The experiment was conducted with leaves of R. serbica collected from nine populations in Kosovo, three in Albania and two in Macedonia, while for R. nathaliae four populations in Macedonia. For this purpose plants after collection from their natural populations were kept for 24 hours at constant temperature and humidity and in natural photoperiod. According to our data the pigment contents (Total chl + Carot) of R. serbica, measured as mg per gram dry weight (DW), were higher (7.06 mg·g-1 DW) in Radaci populations (Kosovo) and lower (4.63 mg·g-1 DW) in Jukniu Mountain-Kruja (Albania). On the other hand, the higher (5.28 mg·g-1 DW) of pigment contents (Total chl + Carot) of R. nathaliae were observed in Vorca populations and the lower (4.24 mg·g-1 DW) in Kaparll?k populations. Ratio chlorophyll a/b of R. serbica in Kruja Castle populations from Albania was the higher (3.68) comparing with Zhlebi populations from Kosovo (1.68). Similarly in case of R. nathaliae the higher (3.36) value was in Kaparll?k populations and the lower (3.12) in Matka populations. The data obtained were further analyzed using one-way ANOVA and a significant change was recorded in the different populations. These studies clearly indicate that the Ramonda plants from different ecological habitats there have been changes of photosynthetic pigment contents.展开更多
The developing mobile technologies have resulted in operators focusing on how to optimize their 2G networks and ensure a smooth network end, there are two approaches for upgrade: one core network with a 2G-radio netwo...The developing mobile technologies have resulted in operators focusing on how to optimize their 2G networks and ensure a smooth network end, there are two approaches for upgrade: one core network with a 2G-radio network, while the other is (Mobile Switching Center) with WCDMA MSCS (Mobile Gateway) to optimize the Core network hierararchy展开更多
文摘The protective role of xanthophyll cycle in resurrection angiosperm Boea hygrometrica (Bunge) R.Br. was investigated by analysis of the changes of chlorophyll fluorescence and xanthophyll cycle components in response to dehydration and rehydration in detached leaves under very weak light condition (3 mumol photons.m(-2).s(-1)) and in the dark. With declines in the values of PSII photochemical efficiency (Fv/Fm), PSII actual quantum yield (Phi(PSII)), photochemical quenching (qP) and non-photochemical quenching (NPQ) during dehydration, zeaxanthin significantly increased in control Boea leaves under very weak light condition, while no zeaxanthin accumulation was detected in Boea leaves treated with dithiothreitol (DTT) and Boea leaves in the dark, and after 3 d rehydration, the parameters Fv/Fm, Phi(PSII), qP and NPQ showed full recovery in control Boea leaves under very weak light condition, but the parameters only underwent partial recovery in Boea leaves treated with DTT and Boea leaves in the dark, suggesting that the recovery of photosystem II (PSII) photochemical activities in Boea leaves was obviously affected by treatments with DTT and darkness, therefore, zeaxanthin may play an important protective role in desiccated Boea leaves even under very weak light conditions.
文摘Resurrection plants which are able to quickly reactivate after falling into a period of anabiosis caused by dehydration have been very rare among angiosperms, especially among dicotyledons whose chlorophyll content and chloroplast structure little changed in the course of desiccation, therefore has been called homoiochlorophyllous desiccation-tolerant plants (HDTs). Another type of resurrection angiosperms that lost its chlorophyll dining desiccation is called poikilochlorophyllous desiccation-tolerant plants (PDTs). HDTs have been received more attention because of simplicity of protection mechanism which is much easy to the study and utilization of the desiccation tolerance of resurrection angiosperms. Recent advances in studies of photosynthesis of resurrection angiosperms indicate that photochemical activities are sensitive indicators for the study of physiological state of resurrection angiosperms during desiccation and rehydration. Photochemical activities of resurrection angiosperms are inhibited with loss of water similar to those of general plants, however, the magic thing is that they could reactivate rapidly during rehydration even losing more than 95% water. Up-regulations in xanthophyll cycle and antioxidative systems as well as preservation in integrity and stability of photosynthetic membranes during desiccation may be very important to desiccation tolerance of resurrection angiosperms. The fact that phosphate treatment in rehydration stage also strongly influences resurrection indicated importance of studies on rehydration stages of resurrection angiosperms.
文摘The resurrection plants Ramonda serbica and Ramonda nathaliae are the physiological model plant and endemic species from Balkan Peninsula. Study was carried out to assess the impact of different populations on photosynthetic pigment contents and their effect on physiological activity of these species. The experiment was conducted with leaves of R. serbica collected from nine populations in Kosovo, three in Albania and two in Macedonia, while for R. nathaliae four populations in Macedonia. For this purpose plants after collection from their natural populations were kept for 24 hours at constant temperature and humidity and in natural photoperiod. According to our data the pigment contents (Total chl + Carot) of R. serbica, measured as mg per gram dry weight (DW), were higher (7.06 mg·g-1 DW) in Radaci populations (Kosovo) and lower (4.63 mg·g-1 DW) in Jukniu Mountain-Kruja (Albania). On the other hand, the higher (5.28 mg·g-1 DW) of pigment contents (Total chl + Carot) of R. nathaliae were observed in Vorca populations and the lower (4.24 mg·g-1 DW) in Kaparll?k populations. Ratio chlorophyll a/b of R. serbica in Kruja Castle populations from Albania was the higher (3.68) comparing with Zhlebi populations from Kosovo (1.68). Similarly in case of R. nathaliae the higher (3.36) value was in Kaparll?k populations and the lower (3.12) in Matka populations. The data obtained were further analyzed using one-way ANOVA and a significant change was recorded in the different populations. These studies clearly indicate that the Ramonda plants from different ecological habitats there have been changes of photosynthetic pigment contents.
文摘The developing mobile technologies have resulted in operators focusing on how to optimize their 2G networks and ensure a smooth network end, there are two approaches for upgrade: one core network with a 2G-radio network, while the other is (Mobile Switching Center) with WCDMA MSCS (Mobile Gateway) to optimize the Core network hierararchy
