Opposite changes in leaf dark respiration and soluble sugars with drought in two Mediterranean oaks

2011 ◽  
Vol 38 (12) ◽  
pp. 1004 ◽  
Author(s):  
Jesús Rodríguez-Calcerrada ◽  
Oula Shahin ◽  
María del Carmen del Rey ◽  
Serge Rambal

The decline in net photosynthetic CO2 uptake (An) caused by drought could reduce the availability of soluble sugars and thus limit leaf dark respiration (Rd). We investigated the response of leaf gas exchange and nonstructural carbohydrates to drought by stopping watering to 2-year-old plants of Quercus ilex L. and Quercus pubescens Willd. grown in large pots. An declined with increasing water deficit more rapidly than Rd, and Rd declined slightly more steeply in Q. ilex than in Q. pubescens. Soluble sugars increased in drought-treated plants relative to control well watered plants, and the opposite pattern was found for starch. After rewatering, Rd returned to pre-drought rates within 2 days and An within 1 week. Soluble sugars tended to recover pre-drought values after rewatering but continued to be significantly higher in drought-treated than control plants of Q. pubescens, for which the increase in the concentration of soluble sugars had been higher. These results suggest that the relative production of soluble sugars is upregulated when An is limited, and that soluble sugars do not control respiratory rates in response to and recovery from water deficit. Rather, we suggest that the decline in Rd contributes to drought tolerance by reducing the consumption of soluble sugars, which play an important role as osmoprotectants during water deficit stress.

2017 ◽  
Vol 45 (1) ◽  
pp. 82-88
Author(s):  
Mahnaz ZAFARI ◽  
Ali EBADI ◽  
Sodabeh JAHANBAKHSH GODEHKAHRIZ

Water deficit is one of the most important environmental stresses that adversely affect crop growth and production and mycorrhizal fungi and symbiotic bacteria have important role in resistance to drought stress. The effect of biofertilizers on alfalfa stress tolerance was studied at the greenhouse condition. Treatments comprised three water-deficit stresses (35%, 55% and 75% of field capacity) and four seeds inoculations (Glomus mosseae, Sinorhizobium meliloti, G. mosseae + S. meliloti and non-inoculated). Water-deficit stress decrease cell membrane stability (39%), total Chl (24.05%), carotenoid (35.55%), quantum yield (50.64%) and forage yield (28.20%), while increased the proline and soluble sugars content (68.55 and 46.53% respectively) and osmotic potential (45.84%). The inoculation of seeds increased the capability of the plants in counteracting the stress, so that the production of compatible solutes was increased and the photosynthetic indices, proline, osmotic potential, membrane stability and forage yield were improved by seed inoculation. Mycorrhiza improved photosynthetic indexes and proline, but bacteria had more efficacy on membrane stability and forage yield. However, double inoculation due to the synergistic effect of mycorrhiza and Sinorhizobium, had the greatest effect than Solitary inoculation. Our results suggest that biofertilized alfalfa plants were better adapted than non- biofertilized ones to cope with water deficit.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0259585
Author(s):  
Gull Mehak ◽  
Nudrat Aisha Akram ◽  
Muhammad Ashraf ◽  
Prashant Kaushik ◽  
Mohamed A. El-Sheikh ◽  
...  

Optimum water availability at different growth stages is one the major prerequisites of best growth and yield production of plants. Exogenous application of plant growth regulators considered effective for normal functioning of plants under water-deficit conditions. A study was conducted to examine the influence of exogenously applied L-methionine on sunflower (Helianthus annuus L.) plants grown under water-deficit conditions. Twenty-five-day old seedlings of four sunflower cultivars, FH331, FH572, FH652 and FH623 were exposed to control (100% F.C.) and drought stress (60% F.C.) conditions. After 30-day of drought stress, L-methionine (Met; 20 mg/L) was applied as a foliar spray to control and drought stressed plants. Water deficit stress significantly reduced shoot fresh and dry weights shoot and root lengths, and chlorophyll a content in all four cultivars. While a significant increase was observed due to water deficiency in relative membrane permeability (RMP), malondialdehyde (MDA), total soluble proteins (TSP), total soluble sugars (TSS), ascorbic acid (AsA) and activity of peroxidase (POD). Although, exogenously applied Met was effective in decreasing RMP, MDA and H2O2 contents, it increased the shoot fresh weight, shoot length, chlorophyll a, chlorophyll a/b ratio, proline contents and the activities of SOD, POD and CAT enzymes in all four cultivars under water deficit stress. No change in AsA and total phenolics was observed due to foliar-applied Met under water stress conditions. Of all sunflower cultivars, cv. FH-572 was the highest and cv. FH-652 the lowest of all four cultivars in shoot fresh and dry weights as well as shoot length under drought stress conditions. Overall, foliar applied L-methionine was effective in improving the drought stress tolerance of sunflower plants that was found to be positively associated with Met induced improved growth attributes and reduced RMP, MDA and H2O2 contents under water deficit conditions.


1978 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
AJ Hall ◽  
FL Milthorpe

Removal of the rapidly growing fruit from a Capsicum plant reduced the rate of net CO2 uptake by its leaves by up to 30% during the time period explored (0.5 - 7 days). This reduction was associated with increases in both the leaf (to about 200%) and intracellular (to about 30%) resistances, these changes having about equal effects on reducing the rate of CO2 uptake. Changes in photorespiration, dark respiration and CO2 compensation point were very small. The rate of CO2 uptake and the associated resistances were also changed by modifying the light regime and other factors affecting the source-sink balance. Changes in the leaf resistance were not attributable to variations in the internal CO2 concentration or in the water economy of the leaf; its control mechanism remains unexplained. The concentration of soluble sugars in the source leaf was completely unaffected but that of polysaccharides was changed by defruiting and by 50% defoliation. However, variations in the intracellular resistance were not closely related to these changes and there is yet no evidence of the nature of its control mechanism. Changes in both soluble sugars and polysaccharides in the stem were more pronounced than in the leaves.


2017 ◽  
Vol 9 (12) ◽  
pp. 259
Author(s):  
Amin Namdari ◽  
Abolfazl Baghbani

Due to low rainfall at early autumn, smooth vetch seedling growth in rain-fed lands often is limited by water deficit stress yet the data regarding the reactions of smooth vetch to water deficit at early growth stages are pretty rare. The objective of current study was to examine possibility of using priming treatments (hydro priming and priming salicylic acid) to alleviate the inhibitory effect of water deficiency during early growth of Smooth Vetch. In this respect, seeds were soaked in distilled water (hydro priming) or 0.5 mM solution of SA for 36 h at 10 °C then dried back to original moisture content. Pots were irrigated for 25 days at four levels of available water containing field capacity (FC), 75% FC, 50% FC and 25% FC. In general, seedling emergence and early growth were markedly limited by increasing water deficiency. However, priming treatments particularly with SA caused considerable improvement in either emergence or growth of seedlings (dry weight, length). The obtained results showed that primed samples exhibited higher accumulation of proline, glycine betaine (GB) under all levels of available water except 100% FC and also higher total soluble sugars (TSS) and trehalose under severe water deficit (25% FC). SA primed samples had higher relative water content especially under higher levels of water deficiency. The more balanced water status within SA primed samples also was accompanied with higher accumulation of proline and glycine betaine. There were significant differences between two priming treatments in terms of proline and GB content within seedlings and SA priming considerably increased proline and GB accumulation. In contrast to proline and GB, TSS and trehalose content wasn’t influenced by SA treatment and both hydro and SA primed samples showed statistically similar quantities.


2018 ◽  
Vol 71 (2) ◽  
Author(s):  
Mehdi Yosefi ◽  
Shahram Sharafzadeh ◽  
Forood Bazrafshan ◽  
Mahdi Zare ◽  
Bahram Amiri

Precise and appropriate management of farmland for a cotton crop to reach the highest water use efficiency with a low water supply and an acceptable yield is required in arid- and semiarid regions. This study in Iran aimed to find the most appropriate concentration of jasmonic acid (JA) and the best stage for application to cope with any negative impacts of water deficit stress. A split-plot factorial experiment based on a randomized complete block design with three replications was used in 2 consecutive years (2016–2017). Two irrigation intervals of 10 and 20 days were used, with four concentrations of JA (0, 25, 50, and 100 mg L<sup>−1</sup> ) and applications at three crop stages (vegetative, reproductive, and vegetative and reproductive together). The final results showed that the 20-day interval significantly decreased relative water content, the quantity of cotton, cotton yield and its related traits including boll number per plant, the 1,000-seed weight, seed cotton yield, lint yield, and lint percentage. It also increased the content of proline and soluble sugars. The 50-mg L<sup>−1</sup> concentration of JA applied at the vegetative-reproductive stages appropriately mitigated the negative effects of water deficit. These results are of practical application for farmers in arid- and semiarid regions with low water supply when irrigating cotton lands in order to reach an acceptable cotton yield.


2021 ◽  
Author(s):  
Fatemeh Ebrahimi ◽  
Amin Salehi ◽  
Mohsen Movahedi Dehnavi ◽  
Amin Mirshekari ◽  
Mohammad Hamidian ◽  
...  

Abstract BackgroundWater-deficit stress is one of the most important sources of damage to crop production worldwide. Adopting appropriate varieties using soil microorganisms such as arbuscular mycorrhiza(AM) can significantly reduce theadverseeffectsofwater deficiency.This study is aimed to evaluate the role of Funneliformismosseaeon nutrients uptake and some physiological traits of two chamomile varieties namely Bodgold (Bod) and Soroksári(Sor) under water-deficit stress. The pot experiment was performed in a hydroponic system within a completely randomized design considering four replications. Three levels of water-deficit stress (PEG 6000) were taken into account at water potentials of -0.4 and -0.8MPa. The second factor was AM inoculation.ResultsWater-deficit stress significantly reduced the uptake of macro-nutrients (N, P, and K) and micro-nutrients (Fe, Cu, Mn, and Zn) in the shoots and roots. Moreover, the level of osmolytes (total soluble sugars and proline) and the activity of antioxidant enzymes in the shoots of both varieties increased under water-deficit stress. In the case of Sor variety, the level of these compounds was more satisfactory. AM improved plant nutrition uptake and osmolyte contents while enhancing antioxidant enzymes and reducing theadverseeffectsofwater-deficit stress. Under water-deficit stress, the growth and total dry weight improved upon AM inoculation. ConclusionsIn general, inoculation of chamomile with AM balanced the uptake of nutrients increased the level of osmolytes, antioxidant enzymes, and hence improved plant characteristics under water-deficit stress in both varieties, however, it was more effective in reducing stress damages in Sor variety.


2021 ◽  
Author(s):  
Fatemeh Ebrahimi ◽  
Amin Salehi ◽  
Mohsen Movahedi Dehnavi ◽  
Amin Mirshekari ◽  
Mohammad Hamidian ◽  
...  

Abstract BackgroundWater-deficit stress is one of the most important sources of damage to crop production worldwide. Adopting appropriate varieties using soil microorganisms such as arbuscular mycorrhiza(AM) fungi can significantly reduce the adverse effects of water deficiency. This study is aimed to evaluate the role of Funneliformis mosseae on nutrients uptake and some physiological traits of two chamomile varieties namely Bodgold (Bod) and Soroksári (Sor) under water-deficit stress. The pot experiment was performed in a completely randomized design with three factors: water-deficit stress (PEG 6000) was applied along with Hoagland solution at three levels (0, -0.4 and -0.8 MPa), two German chamomile varieties (Bodgold (Bod) and Soroksari (Sor)) and AM inoculation (Funneliformis mosseae species (fungal and non-fungal)) at four replications in perlite substrate. ResultsWater-deficit stress significantly reduced the uptake of macro-nutrients (N, P, and K) and micro-nutrients (Fe, Cu, Mn, and Zn) in the shoots and roots. Moreover, the level of osmolytes (total soluble sugars and proline) and the activity of antioxidant enzymes in the shoots of both varieties increased under water-deficit stress. In the case of Sor variety, the level of these compounds was more satisfactory. AM improved plant nutrition uptake and osmolyte contents while enhancing antioxidant enzymes and reducing the adverse effects of water-deficit stress. Under water-deficit stress, the growth and total dry weight improved upon AM inoculation. ConclusionsIn general, inoculation of chamomile with AM balanced the uptake of nutrients increased the level of osmolytes, antioxidant enzymes, and hence improved plant characteristics under water-deficit stress in both varieties, however, it was more effective in reducing stress damages in Sor variety.


2020 ◽  
Vol 34 (6) ◽  
pp. 785-799 ◽  
Author(s):  
Pablo Rosas-Anderson ◽  
Thomas R. Sinclair ◽  
Anna Locke ◽  
Thomas E. Carter ◽  
Thomas W. Rufty

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 36
Author(s):  
Sergio Tombesi ◽  
Tommaso Frioni ◽  
Francesca Grisafi ◽  
Paolo Sabbatini ◽  
Stefano Poni ◽  
...  

Dark respiration (Rd) is a fundamental plant process used to gain biomass and maintain plant physiological activity. It accounts for the metabolization of a large share of the carbon fixed by photosynthesis. However, Rd during conditions of severe plant water stress is still poorly understood. The decrease in leaf transpiration increases temperature, one of the most important drivers of leaf Rd. On the other hand, water stress decreases the pool of leaf carbohydrates, which are the most important substrate for respiration. The aim of the present work was to determine the impact of water shortage on leaf Rd in grapevine and understand the driving factors in modulating leaf Rd response under plant water stress conditions. Water stressed vines had lower Rd as the water shortage severity increased. Rd was correlated with leaf temperature in well-watered vines. Instead, in water stressed vines, Rd correlated with leaf soluble sugars. The decrease of leaf Rd in water stressed vines was due to the decrease of leaf non-structural carbohydrate that, under water stress conditions, exerted a limiting effect on Rd.


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