scholarly journals Effects of Nitrate toxicity on free Proline accumulation, chlorophyll degradation and photosynthetic efficiency in Chlorella vulgaris Beyerinck [Beijerinck]

Author(s):  
İnci Tüney Kızılkaya ◽  
Dilek Unal
1975 ◽  
Vol 53 (23) ◽  
pp. 2893-2896 ◽  
Author(s):  
Robert L. Wample ◽  
J. Derek Bewley

Sunflower accumulates proline in its aerial and subterranean parts when subjected to water stress. Decreases in the proline pool on recovery are slow. Plants that wilted in darkness do not accumulate proline, and plants that are subjected to a 16-h photoperiod and are sprayed with benzyladenine also show reduced accumulation. Flooded plants show increases in their endogenous free-proline pool, which can be reduced by aeration of the roots or by foliar application of benzyladenine. Abscisic acid does not induce free-proline accumulation in unstressed plants.


2004 ◽  
Vol 52 (3) ◽  
pp. 269-276 ◽  
Author(s):  
H. R. Moussa

The effect of CdCl2(0-50 µM) on the growth, physiological parametersand leaf antioxidative enzymes of faba bean plants was studied in order toinvestigate the possible involvement of this metal in the generationof oxidative stress. In the roots and leaves of faba bean plants Cd produceda significant inhibition of growth, as well as a reduction inthe transpiration rate, photosynthetic efficiency (14CO2-fixation), ribulose-1,5-bisphosphate-carboxylase/oxygenase (Rubisco) activity and leaf pigment content, and an alteration in the nutrient status in booth roots and leaves. an increased level of free proline was also detected. The results suggest thatthe treatment of faba bean plants with CdCl2 induced a concentration-dependentoxidative stress situation in the leaves, characterized by an accumulationof  H2O2, as a result of theinhibition of the antioxidant enzymes glutathione reductase (GR) and catalase (CAT). These results point to the possible inductionof leaf senescence by cadmium.


1981 ◽  
Vol 23 (2) ◽  
pp. 86-90 ◽  
Author(s):  
G. Singh ◽  
V. K. Rai

1981 ◽  
Vol 59 (2) ◽  
pp. 349-351 ◽  
Author(s):  
Muneshwar Singh ◽  
T. A. Singh

2020 ◽  
Vol 19 (3) ◽  
pp. 159-165
Author(s):  
Peter Ferus ◽  
Dominika Bošiaková ◽  
Jana Konôpková ◽  
Peter Hoťka

Rhododendrons in numerous gardens in Central Europe are frequently endangered by adverse summer drought periods associated with the climate change. Therefore, in this work drought-resistance strategies in recent genotypes of these highly aesthetic shrubs were investigated. Dehydrated Rhododendron groenlandicum ‘Helma’, R. obtusum ‘Michiko’ and R. hybridum ‘Polarnacht’ showed high initial stomatal conductances (gS), after few days steeply falling to the stable minimum at ca. 20, 85 and 70% leaf relative water content (RWC), respectively. Except of ‘Polarnacht’, they had relatively large specific leaf area and ‘Michiko’ also free proline accumulation. On the other hand, R. repens ‘Scarlet Wonder’ and R. hybridum ‘Red Jack’ started with half gS values, continuously declining 1.5–2 fold longer compared to the first group of genotypes (RWC of ca. 60 and 75%, respectively). Both produced relatively thick leaves but did not show any osmotic adjustment. Among observed drought-resistance strategies, lower and longer period active transpiration with stomata sensitive to the water loss, as found in R. repens ‘Scarlet Wonder’ and R. × hybridum ‘Red Jack’, were accepted as the most effective for drought-affected rhododendron plantations.


2021 ◽  
Vol 146 (1) ◽  
pp. 24-32
Author(s):  
Sylvia Cherono ◽  
Charmaine Ntini ◽  
Misganaw Wassie ◽  
Mohammad Dulal Mollah ◽  
Mohammad A. Belal ◽  
...  

The protective role of melatonin in plants under abiotic stress has been reported, but little information is available on its mitigation effect on coffee (Coffea arabica) plants. The objective of this study was to determine the effect of exogenous application of 100 µM melatonin in coffee leaves under 3 months of drought stress treatment. Melatonin was found to alleviate the drought-induced damage in coffee through reducing the rate of chlorophyll degradation, electrolyte leakage, malonaldehyde content, and activating various antioxidant enzymes, such as catalase, guaiacol peroxidase, and superoxide dismutase. Melatonin application suppressed the expression of chlorophyll degradation gene PAO encoding pheophorbide a oxygenase, and upregulated the expression of photosynthetic gene RBCS2 encoding ribulose-1,5-bisphosphate oxygenase (Rubisco) protein, and a drought-related gene AREB encoding abscisic acid-responsive element binding protein. The photosynthetic efficiency of photosystem II under dark adaptation was also improved upon melatonin application in drought-stressed plants. Our results showed that both foliar spray and direct soil application of melatonin could improve drought tolerance by regulating photosynthetic efficiency and oxidative damage in C. arabica seedlings. This study provides insights in application of melatonin as a protective agent against drought stress in improvement of crop yields.


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