Effects of Stress Conditions and Calcium on the Light-induced Hydrogen Gas Exchange in Oscillatoria chalybea

1999 ◽  
Vol 155 (1) ◽  
pp. 86-92 ◽  
Author(s):  
Refat Abdel-Basset ◽  
Klaus P. Bader
Keyword(s):  
Gas Exchange ◽  
Hydrogen Gas ◽  
Stress Conditions ◽  
Oscillatoria Chalybea ◽  
Effects Of Stress

Characterization of Hydrogen Photoevolution in Oscillatoria chalybea Detected by Means of Mass Spectrometry

1997 ◽  
Vol 52 (11-12) ◽  
pp. 775-781 ◽  
Author(s):  
Refat Abdel-Basset ◽  
Klaus P. Bader
Keyword(s):  
Gas Exchange ◽  
Partial Pressure ◽  
Hydrogen Evolution ◽  
Dark Adaptation ◽  
Molecular Hydrogen ◽  
Chlorophyll Concentration ◽  
Continuous Light ◽  
Direct Determination ◽  
Hydrogen Gas ◽  
Oscillatoria Chalybea

Abstract The filamentous non-heterocystous cyanobacterium Oscillatoria chalybea is capable to photoevolve molecular hydrogen when the cells are flushed to anaerobiosis with nitrogen or argon and exposed to short light flashes or continuous light. The light-induced hydrogen gas exchange of Oscillatoria chalybea has been investigated by direct determination of dynamic changes in the hydrogen partial pressure at m/e=2 in the H/D collector of a mass spectrometric set-up. By means of this technique also the time curves of the light-induced hydrogen gas exchange could be directly recorded. Depending on the chlorophyll concentration in the measuring cell we observed an increasing hydrogen content of the aqueous Oscillatoria suspension i.e. a dark evolution of molecular hydrogen. Upon the onset of light an initial rise of the H 2-signal was observed which was increasingly mixed or followed by a hydrogen uptake. The capability to photoevolve molecular hydrogen was maximal with young cultures and decreased with increasing age. The hydrogen evolution signals require relatively short dark adaptation to get pronounced; few seconds suffice for 2/3 of the hydrogen evolution amplitude. Prolonged dark adaptation maximizes the flash amplitudes. The hydrogen evolu­tion signals do not deactivate by low flash frequency Oscillatoria chalybea evolves molecular hydrogen following growth on nitrogen free or nitrate containing medium. Increase of the oxygen partial pressure of the assays completely abolishes the hydrogen evolution signals with an I50-value of 6 μm.

Leaf gas exchange, chloroplastic pigments and dry matter accumulation in castor bean (Ricinus communis L) seedlings subjected to salt stress conditions

2008 ◽  
Vol 27 (3) ◽  
pp. 385-392 ◽  
Author(s):  
Hugo Alves Pinheiro ◽  
José Vieira Silva ◽  
Laurício Endres ◽  
Vilma Marques Ferreira ◽  
Celene de Albuquerque Câmara ◽  
...  
Keyword(s):  
Salt Stress ◽  
Gas Exchange ◽  
Castor Bean ◽  
Dry Matter ◽  
Ricinus Communis ◽  
Leaf Gas Exchange ◽  
Stress Conditions ◽  
Dry Matter Accumulation ◽  
Ricinus Communis L ◽  
Chloroplastic Pigments

scholarly journals Genotypic Variation in Abscisic Acid Accumulation, Water Relations, and Gas Exchange for Kentucky Bluegrass Exposed to Drought Stress

2003 ◽  
Vol 128 (3) ◽  
pp. 349-355 ◽  
Author(s):  
Zhaolong Wang ◽  
Bingru Huang
Keyword(s):  
Abscisic Acid ◽  
Drought Stress ◽  
Gas Exchange ◽  
Water Relations ◽  
Drought Resistance ◽  
Accumulation Rate ◽  
Kentucky Bluegrass ◽  
Stress Conditions ◽  
Turf Quality ◽  
Aba Content

Drought is a major limiting factor for turfgrass growth. Understanding genetic variations in physiological responses of turfgrass to drought stress would facilitate breeding and management programs to improve drought resistance. This study was designed to evaluate responses of abscisic acid (ABA) accumulation, water relations, and gas exchange to drought stress in four Kentucky bluegrass (Poa pratensis L.) cultivars differing in drought resistance. Plants of `Midnight' and `A82-204' (drought resistant) and `Brilliant' and `RSP' (drought susceptible) were grown under well-watered (control) or drought stress conditions for 25 days in growth chambers. Turf quality, leaf water potential (Ψleaf), relative water content (RWC), leaf net photosynthesis rate (Pn), and stomatal conductance (gs) declined, while electrolyte leakage (EL) increased during drought progression in all cultivars. The magnitudes of the change in these parameters were greater for `RSP' and `Brilliant' than for `Midnight' and `A82-204'. Leaf ABA content in `RSP' and `Brilliant' increased sharply after 2 days of stress to as much as 34 times the control level at 10 days of drought. Leaf ABA content in `Midnight' and `A82-204' also increased with drought, but to a lesser extent than in the other two cultivars. Leaf ABA level was negatively correlated with Ψleaf and gs. `A82-204' had a significantly lower ABA accumulation rate with changes in Ψleaf during drought compared to `Midnight', `RSP' and `Brilliant'; however, no differences in ABA accumulation rate were detected among the latter three cultivars. In addition, leaf gs was more sensitive to changes in ABA accumulation in `Midnight' and `A82-204' than in `RSP' and `Brilliant'. These results demonstrated that drought tolerant cultivars of Kentucky bluegrass were characterized by lower ABA accumulation and less severe decline in Ψleaf, Pn, gs, and turf quality during drought stress than drought sensitive cultivars. Drought tolerance of Kentucky bluegrass could be related to sensitivity of stomata to endogenous accumulation of ABA under drought stress conditions.

scholarly journals Effects of stress conditions on B-value measurement

2016 ◽  
Vol 56 (5) ◽  
pp. 848-860 ◽  
Author(s):  
Yuri Sugiyama ◽  
Katsuyuki Kawai ◽  
Atsushi Iizuka
Keyword(s):  
B Value ◽  
Stress Conditions ◽  
Effects Of Stress ◽  
Value Measurement
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