Changes in Water Relations, Water Flux, and Root Exudate Abscisic Acid Content With Cold Acclimation of Pinus sylvestris L

Scotch pine seedlings (Pinus sylvestris L.) were subjected to 6 week photoperiod and thermoperiod treatments to induce different levels of cold acclimation. The water content, relative water content, xylem pressure potential, transpiration rate, root hydraulic conductance, and abscisic acid (ABA) content of root exudate were then measured. Water content decreased in woody stems and needles with cold acclimation but not in the roots and green stems. There was a close correlation between relative water content and water content of woody stems and needles as well as a decrease in xylem pressure potentials of hardy needles, indicating that the reduction in water content was at least partially due to increased water deficit. The increased water deficit was not caused by increased water loss since transpiration rates decreased in hardy shoots. Water uptake was reduced by decreased root hydraulic conductance which could account for the shoot water deficits. Root hydraulic conductance and transpiration rate returned to non-acclimated levels after warm temperature exposure. ABA levels were highest in the root exudate collected in the morning from non-acclimated plants.

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Aphid fecundity and defenses in wheat exposed to a combination of heat and drought stress

Journal of Experimental Botany ◽

10.1093/jxb/eraa017 ◽

2020 ◽

Vol 71 (9) ◽

pp. 2713-2722 ◽

Cited By ~ 4

Author(s):

Haicui Xie ◽

Jianqin Shi ◽

Fengyu Shi ◽

Haiyun Xu ◽

Kanglai He ◽

...

Keyword(s):

Abscisic Acid ◽

Drought Stress ◽

Water Content ◽

Relative Water Content ◽

Nutritional Quality ◽

Defense Responses ◽

Net Reproductive Rate ◽

Aphid Infestation ◽

Grain Aphid ◽

Relative Water

Abstract Plants are routinely subjected simultaneously to different abiotic and biotic stresses, such as heat, drought, and insect infestation. Plant–insect interactions in such complex stress situations are poorly understood. We evaluated the performance of the grain aphid (Sitobion avenae) in wheat (Triticum aestivum L.) exposed to a combination of heat and drought stresses. We also performed assays of the relative water content, nutritional quality, and responses of phytohormone signaling pathways. Lower relative water content and accumulation of soluble sugars and amino acids were observed in plants exposed to combined heat and drought stress. These conditions increased abscisic acid levels in the absence of aphids, as well as leading to higher levels of jasmonate-dependent transcripts. The grain aphid infestation further increased abscisic acid levels and the abundance of jasmonic acid- and salicylic acid-dependent defenses under the combined stress conditions. Aphids reared on plants grown under drought stress alone showed lower net reproductive rates, intrinsic rates of increase, and finite rates of increase compared with aphids reared on plants in the absence of stress. The heat-treated plants also showed a decreased aphid net reproductive rate. These findings demonstrate that exposure to a combination of stresses enhances plant defense responses against aphids as well as altering nutritional quality.

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Concentrated Exogenous Abscisic Acid Drenches Reduce Root Hydraulic Conductance and Cause Wilting in Tomato

HortScience ◽

10.21273/hortsci.46.12.1640 ◽

2011 ◽

Vol 46 (12) ◽

pp. 1640-1645 ◽

Cited By ~ 3

Author(s):

Manuel G. Astacio ◽

Marc W. van Iersel

Keyword(s):

Abscisic Acid ◽

Water Transport ◽

Water Flux ◽

Hydraulic Conductance ◽

Root Hydraulic Conductance ◽

Fresh Weight ◽

Cumulative Volume ◽

Effective Transport ◽

Relative Water ◽

Root Conductance

Previous work has shown that exogenous abscisic acid (ABA) applications can reduce transpiration, delay wilting, and thereby extend the shelf life of unwatered plants. Paradoxically, we have seen that drenches with concentrated ABA solutions may actually induce wilting. These wilting symptoms occur despite the presence of ample water in the substrate, suggesting that ABA may interfere with the ability of roots to take up water. Our objective was to develop a better understanding of this wilting effect using tomato (Solanum lycopersicum) as a model. In the first study, ABA drenches (125–2000 mg·L−1) reduced transpiration and water use compared with the control plants, yet the relative water content (RWC) of the leaves of ABA-treated plants was lower than that of control plants at 24 h after the ABA drench. Control plants had a leaf RWC of 97%, whereas plants treated ABA had a RWC of 57% to 62%. ABA concentrations of 500 mg·L−1 or higher caused the plants to wilt within 24 h despite the presence of ample water in the substrate. Leaf ABA concentrations 24 h after the ABA application ranged from 2.6 (control) to 62.6 nmol·g−1 fresh weight (FW) in the 2000-mg·L−1 ABA treatment, indicating effective transport of ABA from the roots to the leaves. The reduced leaf RWC suggests that ABA drenches are limiting water transport through the roots to the leaves. The effects of ABA on the hydraulic conductance of the roots and stems of tomatoes were quantified to determine if ABA drenches limit water transport through the roots. The cumulative volume of water conducted by the root systems during a 4-day period ranged from 36.7 mL in the control treatments to 8.1 mL in roots systems drenched with 1000 mg·L−1 ABA, a reduction of 78%. When the conductance study was repeated using decapitated roots and excised stems, root water flux was again reduced by ABA, but water flux through internodal stem sections did not show an ABA effect. Results suggest that ABA-induced wilting is caused by a reduction in root conductance and we hypothesize that ABA affects aquaporins in the roots, limiting water uptake.

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Polyamines in relation to metal concentration, distribution, relative water content and abscisic acid in wheat plants irrigated with waste water heavily polluted with heavy metals

International Journal of Bioassays ◽

10.21746/ijbio.2016.05.002 ◽

2016 ◽

Vol 5 (05) ◽

pp. 4534 ◽

Cited By ~ 2

Author(s):

Heshmat Soliman Aldesuquy

Keyword(s):

Waste Water ◽

Heavy Metals ◽

Abscisic Acid ◽

Water Use Efficiency ◽

Water Content ◽

Water Use ◽

Relative Water Content ◽

Relative Water ◽

Use Efficiency ◽

Growth Vigor

Present study was carried out in order to investigate the effect of grain presoaking in spermine (0.15 mM), spermidine (0.3 mM) and their interaction on growth vigor, metal distribution as well as leaf turgidity and abscisic acid in wheat plants. Waste water at concentrations 25%, 50% and 100% caused noticeable decreases in growth vigor of root and shoot, leaf area, relative water content and water use efficiency. On the other hand, waste water stress caused remarkable increases in heavy metals and saturation water deficit as well as abscisic acid content of flag leaf. Exogenous application of Spm, Spd or their interaction could counteract the adverse effects of heavy metals in waste water by improving growth vigor of root and shoot, water use efficiency, retention of leaf turgidity and decreasing abscisic acid in leaves and grains. Furthermore, these polyamines reduced heavy metals translocation from root to leaves till reach to grains.

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Physiological responses to drought of Cnidoscolus quercifolius Pohl in semi-arid conditions

Advances in Forestry Science ◽

10.34062/afs.v6i1.5735 ◽

2019 ◽

Vol 6 (1) ◽

pp. 493 ◽

Cited By ~ 1

Author(s):

Fabio Rodrigues Ramos ◽

Antonio Lucineudo Oliveira Freire

Keyword(s):

Soil Moisture ◽

Stomatal Conductance ◽

Moisture Content ◽

Water Content ◽

Water Use ◽

Transpiration Rate ◽

Relative Water Content ◽

Soil Moisture Content ◽

Relative Water ◽

Use Efficiency

This study aimed to evaluate the physiological behavior of faveleira (Cnidoscolus quercifolius Pohl) plants grown in the field, in Caatinga, during wet and dry seasons. Adult plants were selected for evaluation in March and April (wet season) and May and June (dry season), during 2016. We evaluated the soil water content, water potential (Ψw), osmotic potential (Ψπ), relative water content (RWC), stomatal conductance (gs), transpiration rate (E), photosynthetic rate (A), intercellular CO2 concentration (Ci), instantaneous water use efficiency (A/E) and carboxylation efficiency (A/Ci). The reduction in water availability in the soil promoted a marked decrease in soil water potential, which was more affected than the relative water content. The opening of the stomata was affected by the decrease in soil moisture content, reducing the stomatal conductance, transpiration rate, photosynthesis rate, instantaneous water use efficiency and carboxylation efficiency. The photosynthesis was more affected than transpiration by the reduction in soil moisture content.

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Nanopotassium, Nanosilicon, and Biochar Applications Improve Potato Salt Tolerance by Modulating Photosynthesis, Water Status, and Biochemical Constituents

Sustainability ◽

10.3390/su14020723 ◽

2022 ◽

Vol 14 (2) ◽

pp. 723

Author(s):

Abdel Wahab M. Mahmoud ◽

Mahmoud M. Samy ◽

Hoda Sany ◽

Rasha R. Eid ◽

Hassan M. Rashad ◽

...

Keyword(s):

Abscisic Acid ◽

Plant Growth ◽

Water Content ◽

Chlorophyll Content ◽

Acid Content ◽

Relative Water Content ◽

Combined Treatment ◽

Potato Plants ◽

Relative Water ◽

Abscisic Acid Content

Salinity is one of the main environmental stresses, and it affects potato growth and productivity in arid and semiarid regions by disturbing physiological process, such as the photosynthesis rate, the absorption of essential nutrients and water, plant hormonal functions, and vital metabolic pathways. Few studies are available on the application of combined nanomaterials to mitigate salinity stress on potato plants (Solanum tuberosum L. cv. Diamont). In order to assess the effects of the sole or combined application of silicon (Si) and potassium (K) nanoparticles and biochar (Bc) on the agro-physiological properties and biochemical constituents of potato plants grown in saline soil, two open-field experiments were executed on a randomized complete block design (RCBD), with five replicates. The results show that the biochar application and nanoelements (n-K and n-Si) significantly improved the plant heights, the fresh and dry plant biomasses, the numbers of stems/plant, the leaf relative water content, the leaf chlorophyll content, the photosynthetic rate (Pn), the leaf stomatal conductance (Gc), and the tuber yields, compared to the untreated potato plants (CT). Moreover, the nanoelements and biochar improved the content of the endogenous elements of the plant tissues (N, P, K, Mg, Fe, Mn, and B), the leaf proline, and the leaf gibberellic acid (GA3), in addition to reducing the leaf abscisic acid content (ABA), the activity of catalase (CAT), and the peroxidase (POD) and polyphenol oxidase (PPO) in the leaves of salt-stressed potato plants. The combined treatment achieved maximum plant growth parameters, physiological parameters, and nutrient concentrations, and minimum transpiration rates (Tr), leaf abscisic acid content (ABA), and activities of the leaf antioxidant enzymes (CAT, POD, and PPO). Furthermore, the combined treatment also showed the highest tuber yield and tuber quality, including the contents of carbohydrates, proteins, and the endogenous nutrients of the tuber tissues (N, P, and K), and the lowest starch content. Moreover, Pearson’s correlation showed that the plant growth and the tuber yields of potato plants significantly and positively correlated with the photosynthesis rate, the internal CO2 concentration, the relative water content, the proline, the chlorophyll content, and the GA3, and that they were negatively correlated with the leaf Na content, PPO, CAT, ABA, MDA, and Tr. It might be concluded that nanoelement (n-K and n-Si) and biochar applications are a promising method to enhance the plant growth and crop productivity of potato plants grown under salinity conditions.

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Phytotoxic effects of industrial and sewage waste waters on growth, chlorophyll content, transpiration rate and relative water content of potted sunflower plants

Water Air & Soil Pollution ◽

10.1007/bf00300420 ◽

1996 ◽

Vol 89 (1-2) ◽

pp. 33-47 ◽

Cited By ~ 11

Author(s):

M. A. A. Gadallah

Keyword(s):

Water Content ◽

Chlorophyll Content ◽

Transpiration Rate ◽

Relative Water Content ◽

Waste Waters ◽

Phytotoxic Effects ◽

Relative Water ◽

Sewage Waste

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Interaction of Salinity and Phytohormones on Wheat Photosynthetic Traits and Membrane Stability

Agriculture (Pol nohospodárstvo) ◽

10.2478/agri-2013-0004 ◽

2013 ◽

Vol 59 (1) ◽

pp. 33-41 ◽

Cited By ~ 1

Author(s):

Arman Pazuki ◽

Mohammad Sedghi ◽

Fatemeh Aflaki

Keyword(s):

Abscisic Acid ◽

Chlorophyll Fluorescence ◽

Stomatal Conductance ◽

Gibberellic Acid ◽

Water Content ◽

Chlorophyll Content ◽

Relative Water Content ◽

Acid Treatment ◽

Membrane Stability ◽

Relative Water

To evaluate phytohormones effects on stomatal conductance, chlorophyll fluorescence, membrane stability, relative water content and chlorophyll content under salinity, a factorial experiment with 4 replicates was conducted. Treatments were salinity (0, 3.5 and 7 dS/m), phytohormones (control, gibberellic acid and abscisic acid) and wheat cultivars (Gascogen, Zagros, and Kuhdasht). Results showed that a high level of salinity increased chlorophyll fluorescence and relative water content, while membrane stability, chlorophyll content, and stomatal conductance were decreased. Abscisic acid treatment had more effective role in membrane stability. Although membrane stability was much more under gibberellic acid treatment, restoration of membrane stability was considerable under abscisic acid treatment for Gascogen and Kuhdasht cultivars. Spraying of gibberellic acid induced the highest chlorophyll content in the three salinity levels and all of the cultivars. The maximum amount of stomatal conductance was achieved under gibberellic acid treatment. Abscisic acid caused less chlorophyll fluorescence in comparison to gibberellic acid. About relative water content, abscisic acid was effective in high salinity levels so that it caused stomatal closure, which reduced water loss and maintained turgor in plants.

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The Method of Plant Water Status Measurement in Sweet Potato (Ipomoea Batatas (L) Lam.)

Beccariana Botanical Research Bulletin ◽

10.30862/bbrp.v7i1.274 ◽

2010 ◽

Vol 7 (1) ◽

Author(s):

Saraswati Prabawardani

Keyword(s):

Water Content ◽

Sweet Potato ◽

Relative Water Content ◽

Water Status ◽

Plant Water Status ◽

Equilibration Time ◽

Plant Water ◽

Font Size ◽

Potato Leaf ◽

Relative Water

The measurement of plant water status such as leaf water potential (LWP) and leaf relative water content (RWC) is important part of understanding plant physiology and biomass production. Preliminary study was made to determine the optimum amount of leaf abrasion and equilibration time of sweet potato leaf inside the thermocouple psychrometer chambers. Based on the trial, the standard equilibration time curve of a Peltier thermocouple for sweet potato leaf was between 2 and 3 hours. To increase the water vapour conductance across the leaf epidermis the waxy leaf cuticle should be removed or broken by abrasion. The result showed that 4 times leaf rubbings was accepted as the most effective way to increase leaf vapour conductance of sweet potato in the psychrometer chambers. In calculating the leaf relative water content, unstressed water of sweet potato leaves require 4 hours imbibition, whereas water stressed of sweet potato leaves require 5 to 6 hours to reach the saturation time. Either leaf water potential or relative water content can be used as a parameter for plant water status in sweet potato.

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Palmer Amaranth (Amaranthus palmeri) Competition for Water in Cotton

Weed Science ◽

10.1614/ws-d-15-00062.1 ◽

2015 ◽

Vol 63 (4) ◽

pp. 928-935 ◽

Cited By ~ 11

Author(s):

Sarah T. Berger ◽

Jason A. Ferrell ◽

Diane L. Rowland ◽

Theodore M. Webster

Keyword(s):

Water Content ◽

Relative Water Content ◽

Yield Loss ◽

Linear Trend ◽

Palmer Amaranth ◽

Cotton Production ◽

Excess Water ◽

Relative Water ◽

Competition For Light ◽

Daily Water

Palmer amaranth is a troublesome weed in cotton production. Yield losses of 65% have been reported from season-long Palmer amaranth competition with cotton. To determine whether water is a factor in this system, experiments were conduced in 2011, 2012, and 2013 in Citra, FL, and in Tifton, GA. In 2011, infrequent rainfall lead to drought stress. The presence of Palmer amaranth resulted in decreased soil relative water content up to 1 m in depth. Cotton stomatal conductance (gs) was reduced up to 1.8 m from a Palmer amaranth plant. In 2012 and 2013 higher than average rainfall resulted in excess water throughout the growing season. In this situation, no differences were found in soil relative water content or cottongsas a function of proximity to Palmer amaranth. A positive linear trend was found in cotton photosynthesis and yield; each parameter increased as distance from Palmer amaranth increased. Even in these well-watered conditions, daily water use of Palmer amaranth was considerably higher than that of cotton, at 1.2 and 0.49 g H20 cm−2d−1, respectively. Although Palmer amaranth removed more water from the soil profile, rainfall was adequate to replenish the profile in 2 of the 3 yr of this study. However, yield loss due to Palmer amaranth was still observed despite no change ings, indicating other factors, such as competition for light or response to neighboring plants during development, are driving yield loss.

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