scholarly journals Long-term high light stress induces leaf senescence in wheat (Triticum aestivum L.)

2019 ◽  
Vol 57 (3) ◽  
pp. 830-840 ◽  
Author(s):  
Y.N. LIU ◽  
Q.Z. XU ◽  
W.C. LI ◽  
X.H. YANG ◽  
Q. ZHENG ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Leaf Senescence ◽  
Light Stress ◽  
Triticum Aestivum L ◽  
High Light ◽  
High Light Stress

Photoprotection of PSII in Hawaiian lobeliads from diverse light environments

2008 ◽  
Vol 35 (7) ◽  
pp. 595 ◽  
Author(s):  
Rebecca A. Montgomery ◽  
Guillermo Goldstein ◽  
Thomas J. Givnish
Keyword(s):  
Light Stress ◽  
Common Garden ◽  
High Irradiance ◽  
High Light ◽  
Maximum Efficiency ◽  
Light Responses ◽  
Percentage Recovery ◽  
High Light Stress ◽  
Sustained Reduction

Excess irradiance can reduce the quantum yield of photosynthesis via photoprotective energy dissipation, inactivation or downregulation of PSII. We examined variation in photoprotection as part of a study of adaptive radiation in photosynthetic light responses by Hawaiian lobeliads. We measured the maximum efficiency of PSII (Fv/Fm) and recovery of Fv/Fm after high light stress in field populations of 11 lobeliad species and in four species growing under common-garden greenhouse conditions. Species showed no difference in Fv/Fm (0.82 ± 0.02 (mean ± s.e.)) or in their ability to recover from light stress under field conditions. Average recovery was 74 ± 1.4% within 1 h of removal of the stress suggesting that all species maintain the ability to recover from high light stress, at least in the short-term. In contrast, the results from the common-garden indicate that long-term exposure to high irradiance and associated higher temperatures can cause a sustained reduction in PSII function. Species showed decreased Fv/Fm and percentage recovery as treatment irradiance increased. Fv/Fm and percentage recovery were positively related to native habitat PFD across species, suggesting that there has been a diversification in high light tolerance, with species from sunnier environments better able to avoid sustained declines in PSII function.

scholarly journals Photoinhibition of photosynthesis in Antarctic lichen Usnea antarctica. I. Light intensity- and light duration-dependent changes in functioning of photosystem II

2012 ◽  
Vol 2 (1) ◽  
pp. 42-51 ◽  
Author(s):  
Miloš Barták ◽  
Josef Hájek ◽  
Petra Očenášová
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Light Stress ◽  
Term Treatment ◽  
High Light ◽  
Short Term ◽  
High Light Stress ◽  
Long Term Treatment ◽  
James Ross Island

The paper deals with the differences in sensitivity of Antarctic lichen to photoinhibition. Thalli of Usnea antarctica were collected at the James Ross Island, Antarctica (57°52´57´´W, 63°48´02´´S) and transferred in dry state to the Czech Republic. After rewetting in a laboratory, they were exposed to 2 high light treatments: short-term (30 min), and long-term (6 h). In short-term treatment, the sample were exposed to 1000 and 2000 µmol m-2 s-1 of photosynthetically active radiation (PAR). In long-term experiment, PAR of 300, 600, and 1000 µmol m-2 s-1 were used. Photosynthetic efficiency of U. antarctica thalli was monitored by chlorophyll fluorescence parameters, potential (FV/FM) and actual (FPSII) quantum yield of photochemical processes in photosystem II in particular. In short-term treatments, the F0, FV and FM signals, as well as the values of FV/FM, and FPSII showed light-induced decrease, however substantial recovery after consequent 30 min. in dark. Longer exposition (60 min) to high light led to more pronounced decrease in chlorophyll fluorescence than after 30 min treatment, however dark recovery was faster in the thalli treated before for longer time (60 min). Long-term treatment by high light caused gradual decrease in FV/FM and FPSII with the time of exposition. The extent of the decrease was found light dose-dependent. The time course was biphasic for FV/FM but not for FPSII. The study showed that wet thalli of Usnea antarctica had high capacity of photoprotective mechanisms to cope well either with short- or long-term high light stress. This might be of particular importance in the field at the James Ross Island, particularly at the begining of growing season when melting water is available and, simultaneously, high light stress may happen on fully sunny days.

scholarly journals Tracking Changes on Soil Structure and Organic Carbon Sequestration after 30 Years of Different Tillage and Management Practices

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 291
Author(s):  
Ramón Bienes ◽  
Maria Jose Marques ◽  
Blanca Sastre ◽  
Andrés García-Díaz ◽  
Iris Esparza ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Organic Carbon ◽  
Management Practices ◽  
Management Strategies ◽  
Triticum Aestivum L ◽  
Field Trials ◽  
Conventional Tillage ◽  
Soil Parameters ◽  
Wilting Point

Long-term field trials are essential for monitoring the effects of sustainable land management strategies for adaptation and mitigation to climate change. The influence of more than thirty years of different management is analyzed on extensive crops under three tillage systems, conventional tillage (CT), minimum tillage (MT), and no-tillage (NT), and with two crop rotations, monoculture winter-wheat (Triticum aestivum L.) and wheat-vetch (Triticum aestivum L.-Vicia sativa L.), widely present in the center of Spain. The soil under NT experienced the largest change in organic carbon (SOC) sequestration, macroaggregate stability, and bulk density. In the MT and NT treatments, SOC content was still increasing after 32 years, being 26.5 and 32.2 Mg ha−1, respectively, compared to 20.8 Mg ha−1 in CT. The SOC stratification (ratio of SOC at the topsoil/SOC at the layer underneath), an indicator of soil conservation, increased with decreasing tillage intensity (2.32, 1.36, and 1.01 for NT, MT, and CT respectively). Tillage intensity affected the majority of soil parameters, except the water stable aggregates, infiltration, and porosity. The NT treatment increased available water, but only in monocropping. More water was retained at the permanent wilting point in NT treatments, which can be a disadvantage in dry periods of these edaphoclimatic conditions.

scholarly journals Long-Term Winter Wheat (Triticum aestivum L.) Seasonal Irrigation Amount, Evapotranspiration, Yield, and Water Productivity under Semiarid Climate

Agronomy ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 96 ◽  
Author(s):  
Koffi Djaman ◽  
Michael O’Neill ◽  
Curtis Owen ◽  
Daniel Smeal ◽  
Margaret West ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Water Productivity ◽  
Triticum Aestivum L ◽  
Irrigation Amount ◽  
Semiarid Climate ◽  
Seasonal Irrigation

Nitric oxide mediates abscisic acid induced light-tolerance in leaves of tall fescue under high-light stress

2013 ◽  
Vol 162 ◽  
pp. 1-10 ◽  
Author(s):  
Yuefei Xu ◽  
Juanjuan Fu ◽  
Xitong Chu ◽  
Yongfang Sun ◽  
He Zhou ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Abscisic Acid ◽  
Tall Fescue ◽  
Light Stress ◽  
High Light ◽  
High Light Stress
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