Search

Start Over Format bez média Language Multiple languages

393. Chill-induced inhibition of photosynthesis was alleviated by 24-epibrassinolide pretreatment in cucumber during chilling and subsequent recovery

Creator:
Hu, W. H., Wu, Y., Zeng, J. Z., He, L., and Zeng, Q. M.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, antioxidant enzymes, brassinosteroids, chlorophyll fluorescence, cfhilling stress, Cucumis sativau L., photosynthesis, and reactive oxygen species
Language:
Multiple languages
Description:
To investigate whether brassinosteroids (BRs) could be used to alleviate chill-induced inhibition of photosynthesis in cucumber (Cucumis sativus L) during chilling and subsequent recovery, the effects of exogenously applied 24-epibrassinolide (EBR) on gas exchange, chlorophyll fluorescence parameters, and antioxidant enzyme activity were studied. Cucumber plants were exposed to chilling under low light (12/8°C and 100 μmol m-2 s-1 PPFD) for 3 days and then recovered under normal temperature and high irradiance (28/18°C and 600 μmol m-2 s-1 PPFD) for 6 days. Chilling significantly decreased the net photosynthetic rate (PN) and stomatal conductance (g s), and increased rate of O2 .- formation and H2O2 and malondialdehyde (MDA) content in cucumber leaves, but did not influence the optimal quantum yield of PSII (Fv/Fm). Chilling also decreased the effective quantum yield of PSII photochemistry (ΦPSII) and photochemical quenching (qP), but induced an increase in nonphotochemical quenching (NPQ), and the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX). High irradiance (600 μmol m-2 s-1) further aggravated the decrease in PN, gs, ΦPSII and qP, and enhanced the increase in reactive oxygen species (ROS) generation and accumulation in the first day of recovery after chilling. However, high irradiance induced a sharp decrease in Fv/Fm and NPQ, as well as the activities of SOD and APX on the first day of recovery. EBR pretreatment significantly alleviated chill-induced inhibition of photosynthesis during chilling stress and subsequent recovery period, which was mainly due to significant increases in gs, ΦPSII, qP and NPQ. EBR pretreatment also reduced ROS generation and accumulation, and increased the activities of SOD and APX during chilling and subsequent recovery. Those results suggest that EBR pretreatment alleviates the chill reduction in photosynthesis and accelerated the recovery rate mainly by increasing of the stomatal conductance, the efficiency of utilization and dissipation of leaf absorbed light, and the activity of the ROS scavenging system during chilling and subsequent recovery period. and W. H. Hu ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

394. Chilling stress and chilling tolerance of sweet potato as sensed by chlorophyll fluorescence

Creator:
Lin, K. H., Hwang, W. C., and Lo, H. F.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
cultivar differences, Ipomoea, photosystem 2, and quantum yield
Language:
Multiple languages
Description:
We studied changes in the chlorophyll (Chl) fluorescence components in chilling-stressed sweet potato (Ipomoea batatas L. Lam) cv. Tainung 57 (TN57, chilling-tolerant) and cv. Tainung 66 (TN66, chilling-susceptible). Plants under 12-h photoperiod and 400 µmol m-2 s-1 irradiance at 24/20 °C (day/night) were treated by a 5-d chilling period at 7/7 °C. Compared to TN66, TN57 exhibited a significantly greater basic Chl fluorescence (F0), maximum fluorescence (Fm), maximum fluorescence yield during actinic irradiation (Fm' ), and the quantum efficiency of electron transport through photosystem 2, PS2 (ΦPS2). Chilling stress resulted in decrease in the potential efficiency of PS2 (Fv/Fm), ΦPS2, non-photochemical fluorescence quenching (NPQ), non-photochemical quenching (qN), and the occurrence of chilling injury in TN66. Chilling increased the likelihood of photoinhibition, characterized by a decline in the Chl fluorescence of both cultivars, and photoinhibition during low temperature stress generally occurred more rapidly in TN66. and K. H. Lin, W. C. Hwang, H. F. Lo.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

395. Chilling tolerance and early vigour-related characteristics evaluated in two Miscanthus genotypes

Creator:
Fonteyne, S., Lootens, P., Muylle, H., van den Ende, W., De Swaef, T., Reheul, D., and Roldan-Ruiz, I.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
photosynthesis, bioenergy crop, chlorophyll fluorescence, cold tolerance, leaf growth analysis, low temperature stress, 2, and 581
Language:
Multiple languages
Description:
A long growing season, mediated by the ability to grow at low temperatures early in the season, can result in higher yields in biomass of crop Miscanthus. In this paper, the chilling tolerance of two highly productive Miscanthus genotypes, the widely planted Miscanthus × giganteus and the Miscanthus sinensis genotype ‘Goliath’, was studied. Measurements in the field as well as under controlled conditions were combined with the main purpose to create basic comparison tools in order to investigate chilling tolerance in Miscanthus in relation to its field performance. Under field conditions, M. × giganteus was higher yielding and had a faster growth rate early in the growing season. Correspondingly, M. × giganteus displayed a less drastic reduction of the leaf elongation rate and of net photosynthesis under continuous chilling stress conditions in the growth chamber. This was accompanied by higher photochemical quenching and lower nonphotochemical quenching in M. × giganteus than that in M. sinensis ‘Goliath’ when exposed to chilling temperatures. No evidence of impaired stomatal conductance or increased use of alternative electron sinks was observed under chilling stress. Soluble sugar content markedly increased in both genotypes when grown at 12°C compared to 20°C. The concentration of raffinose showed the largest relative increase at 12°C, possibly serving as a protection against chilling stress. Overall, both genotypes showed high chilling tolerance for C4 plants, but M. × giganteus performed better than M. sinensis ‘Goliath’. This was not due to its capacity to resume growth earlier in the season but rather due to a higher growth rate and higher photosynthetic efficiency at low temperatures., S. Fonteyne, P. Lootens, H. Muylle, W. van den Ende, T. de Swaef, D. Reheul, I. Roldan-Ruiz., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

396. Chilling-induced photoinhibition in two oak species: Are evergreen leaves inherently better protected than deciduous leaves?

Creator:
Cavender-Bares, J., Apostol, S., Moya, I., Briantais, J.-M., and Bazzaz, F. A.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chlorophyll fluorescence, evergreen and deciduous trees, leaf habit, non-photochemical quenching, photoprotection, Quercus michauxii, and Quercus virginiana
Language:
Multiple languages
Description:
We compared the sensitivity to cold stress, in terms of photosynthetic capacity and changes in chlorophyll fluorescence of photosystem 2 (PS2), of an evergreen and a deciduous oak species, which co-occur in the southeastern United States. We predicted that the evergreen species, Quercus virginiana, which must endure winter, is likely to have an inherently greater capacity for energy dissipation and to be less susceptible to chilling stress than the deciduous species, Quercus michauxii. Short-term cold stress in both species lead to greater than 50 % reduction in maximum photosynthetic rates, 60-70 % reduction in electron transport, and irreversible quenching of PS2 fluorescence. The kinetics of recovery in the dark after exposure to 1 h high irradiance (1000 µmol m-2 s-1) and chilling (5 °C) showed that the evergreen Q. virginiana exhibited more protective qE and less irreversible quenching (qI) than the deciduous Q. michauxii. The large qE which we observed in Q. virginiana suggests that the capacity for photoprotection at low temperatures is not induced by a long-term acclimation to cold but preexists in evergreen leaves. This capacity may contribute to the ability of this species to maintain leaves during the winter. and J. Cavender-Bares ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

397. Chilling-induced reduction of photosynthesis is mitigated by exposure to elevated CO2 concentrations

Creator:
Arena, C. and Vitale, L.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, chilling, elevated CO2, partitioning of absorbed light to PSII, photosynthetic rate, 2, and 581
Language:
Multiple languages
Description:
This work aimed to evaluate if chilling stress may be mitigated by elevated CO2 (EC) in Beta vulgaris L. plants. Photosynthetic rate was measured at 21% and 2% O2 after a short-term exposure of 5 h at four different treatments: 360 μmol(CO2) mol-1/25°C (AC); 360 μmol(CO2) mol-1/4°C (AC+LT); 700 μmol(CO2) mol-1/25°C (EC); 700 μmol(CO2) mol-1/4°C (EC+LT). Compared to AC+LT, EC+LT plants showed higher values of CO2 fixation, photochemical activity, and Rubisco amount. These latter invest a higher portion of photosynthetic electron flow to O2, differently from AC+LT plants that promote the regulated thermal dissipation processes. In EC+LT plants, the photosynthetic electron flow to O2 acts as a safety mechanism against the excess of absorbed light, upon return to prechilling conditions, allowing photosynthetic apparatus to maintain its efficiency. In AC+LT plants, the increase of thermal dissipation processes was not adequate to guarantee the PSII photoprotection and the photosynthetic recovery after chilling., C. Arena, L. Vitale., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

398. Chlorophyll a fluorescence analysis in response to excitation irradiance in bean plants (Phaseolus vulgaris L. and Vigna unguiculata L. Walp) submitted to high temperature stress

Creator:
Costa, E. S., Bressan-Smith, R., Oliveira, J. G., and Campostrini, E.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
electron transport rate, net photosynthetic rate, and photochemical and non-photochemical quenching
Language:
Multiple languages
Description:
Bean plants Phaseolus vulgaris L. (cv. Carioca and Negro Huasteco) and Vigna unguiculata L. Walp (cv. Epace-10) were grown in a growth chamber with a photosynthetic photon flux density of 200 μmol m-2 s-1 at leaf level and air temperature of 25+1 °C. Fully expanded, first pair leaves of 12-d-old plants were submitted for 90 min to high temperature (25, 30, 35, 40, 45, and 48 °C). Chlorophyll a fluorescence parameters (ETR, qP, qN, and F0) were investigated using a modulated fluorimeter at 25 °C during recovery considered here as 48 h after stress induction period. An accentuated decrease in qP and an increase in qN at 48 °C in Carioca and Negro Huasteco was not observed in Epace-10. In response to excitation irradiance a great potential for ETR was found in Negro Huasteco at 25 °C, also demonstrated by net photosynthetic rate. At 48 °C ETR was high for Epace-10 while it was equal to zero for Carioca and Negro Huasteco. Tolerance to high temperature observed in Epace-10 provided important information about the adaptative characteristics of Vigna cultivars to warm climates. and E. S. Costa ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

399. Chlorophyll a fluorescence analysis of high-yield rice (Oryza sativa L.) LYPJ during leaf senescence

Creator:
Wang, Y. W., Xu, C., Lv, C. F., Wu, M., Cai, X. J., Liu, Z. T., Song, X. M., Chen, G. X., and Lv, C. G.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, thylakoid membrane, JIP-test, natural senescence, PSII efficiency, 2, and 581
Language:
Multiple languages
Description:
Photosystem II (PSII) photochemistry was examined by chlorophyll (Chl) a fluorescence analysis in high-yield rice LYPJ flag leaves during senescence. Parameters deduced from the JIP-test showed that inhibition of the donor side of PSII was greater than that of the acceptor side in hybrid rice LYPJ. The natural senescence process was accompanied by the increased inactivation of oxygen-evolving complex (OEC) and a lower total number of active reaction centers per absorption. It indicated that the inhibition of electron transport caused by natural senescence might be caused partly by uncoupling of the OEC and/or inactivation of PSII reaction centers. Chl fluorescence parameters analyzed in this study suggested that energy dissipation was enhanced in order to protect senescent leaves from photodamage. Nevertheless, considerably reduced PSI electron transport activity was observed at the later senescence. Thus, natural senescence inhibited OEC-PSII electron transport, but also significantly limited the PSII-PSI electron flow., Y. W. Wang, C. Xu, C. F. Lv, M. Wu, X. J. Cai, Z. T. Liu, X. M. Song, G. X. Chen, C. G. Lv., and Seznam literaruty
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

400. Chlorophyll a fluorescence as a tool for a study of the Potato virus Y effects on photosynthesis of nontransgenic and transgenic Pssu-ipt tobacco

Creator:
Spoustová, P., Synková, Helena, Valcke, R., and Čeřovská, N.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, chlorophyll a fluorescence imaging, cytokinins, gas-exchange parameters, ipt, photosynthesis, Potato virus Y, transgenic tobacco, 2, and 58
Language:
Multiple languages
Description:
The effect of Potato virus Y NTN (PVY) infection upon photosynthesis was analysed in transgenic Pssu-ipt tobacco overproducing endogenous cytokinins in comparison with control, nontransgenic Nicotiana tabacum plants. The course of the infection from the early to the late stage was monitored by measuring of photosynthetic gas exchange and fast chlorophyll (Chl) a fluorescence induction kinetics. Leaf photosynthesis was also analysed using Chl fluorescence imaging (Chl-FI). From the different fluorescence parameters obtained using Chl-FI, the nonphotochemical quenching (NPQ) proved to be the most useful parameter to assess the effect of PVY infection. On the other hand, Chl-FI was found to be inapplicable for any presymptomatic detection of PVY infection in tobacco. The lower accumulation of the virus was found in transgenic plants and corresponded also with the presence of visible symptoms of PVY infection. The net photosynthetic rate (PN), transpiration rate (E), and stomatal conductance (gs) significantly decreased with the progress of the infection in both control plant types and transgenic rooted plants, while transgenic grafts were much less affected. The analysis of the Chl fluorescence transient revealed higher number of silent dissipative reaction centres, higher nonphotochemical dissipation, and significantly lower performance index, PI(abs), in the healthy transgenic grafts. Chl-FI also confirmed significantly higher NPQ in transgenic grafts., P. Spoustová ... [et al.]., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

Limit your search