Antitranspirant Research Articles

Estimation of film antitranspirant spray coverage on rapeseed (Brassica napus L.) leaves using titanium dioxide

Film antitranspirant (AT) forms a physical layer to block stomata on the leaf surface and thus improve plant water status under drought. There is little understanding of how leaf coverage relates to the physiological mechanism, so a reliable method of evaluating AT spray deposition is needed. Titanium dioxide (TiO2) is widely applied to heighten the whiteness, brightness and opacity of materials, which can be potentially used as an inert marker to visualize AT deposited on leaves. This study aimed to evaluate the effect of TiO2 on the spray characteristics and coverage of film AT (a.i. di-1-p-menthene) on water-sensitive papers (WSP) and its subsequent use to explore the dose-response relationship between this AT and leaf coverage. Spray characteristics when applied through standard 110° flat fan nozzles were assessed using a droplet analyzer and coverage was measured using image analysis of deposition on water sensitive paper (WSP) and oilseed rape leaves. There was no significant difference observed with TiO2 added to film AT and water in droplet size spectra. Spray coverage averaged 46.8% and 57.3% respectively when WSP were positioned at 70 cm and 50 cm below nozzles. Adding TiO2 to AT solutions with different dose rates had no significant effects on WSP spray coverage at either nozzle height. Leaf coverage was positively correlated with the dose rates of AT at the distance of 50 cm from nozzles to the canopy. Overall, results suggest that TiO2 did not affect droplet size spectra or deposition on WSP of the AT when applied through a flat fan nozzle. Therefore, TiO2 can be effective as a tool to estimate the leaf coverage of film AT on rapeseed for use in future physiological studies.

Increasing survival and efficacy of splice-grafted watermelon using sucrose and antitranspirant

Increasing survival and efficacy of splice-grafted watermelon using sucrose and antitranspirant

Postharvest performance of cut rose cv. Lovely Red as affected by osmoprotectant and antitraspirant compounds

In cut flowers, the post-harvest turgor is a critical aspect in a system in which, in the absence of the root system, transpiration water losses must be compensated. Two experiments were conducted in order to elucidate the effect of osmoprotectants (L-Proline) as well as of molecules with antitranspirant behavior (s-aminobutyric acid - BABA or Pinolene) on the water relations and vase life of rose cut stems. Applications of L-Proline enhanced water fluxes, water conductivity, relative water content and stomatal conductance of rose cut stems in comparison to untreated plants, thus increasing the vase-life of rose cut flowers. BABA treatment reduced the stomatal conductance in rose as well as the daily water consumption, on the other hand senescence phenomena occurred earlier. The water used by pinolene treated stems was lower compared to the control and this was associated with a medium increase of the vase life. Overall, enhanced osmoregulation prolonged the vase life of cut flowers since the improved water status allowed the cut stem to partially continue its metabolic functions. On the other hand, the control of transpirational flux was functional in maintaining cellular turgor in pinolene treated cut stems, whereas with BABA, senescence phenomena occurred probably due to the activation of biochemical pathway of senescence involving abscisic acid. Taking all together, osmoregulation or direct control of transpirational fluxes may provide a promising avenue for improving the post-harvest longevity of cut roses.

Reduction of plant water consumption through anti-transpirants foliar application in tomato plants ( Solanum lycopersicum L )

Abstract Optimizing water use efficiency (WUE) is a crucial goal worldwide. However, water savings must not be made at the expense of yield and/or fruit quality to secure economical sustainability for producers. A field study was undertaken to investigate the impact of different anti-transpirants (ATS) on WUE, water requirements (WR), net carbon assimilation rate (P-net), yield and fruit quality of tomato plants (Solanum lycopersicum L.). The aim of this study was to select the most suitable anti-transpirant (AT) that produces a satisfactory yield with less water under field conditions. Three types of ATS were sprayed at first fruit set stage: kaolin (KA) 3% and 5% as a reflective AT, Emulsion of Linus seed Oil tri-ethanolamine (ELO) 1% and 2% as a film forming AT and Fulvic acid (FA) 0.15% and 0.2% as a metabolic AT. The results showed that ATS application increased the relative water content (RWC) especially in the case of FA. However, CO2 assimilation rate was reduced with the minimum reduction observed under FA application. KA application reduced the canopy temperature (Ct) meanwhile, FA and ELO had no effect. ATS significantly reduced tomato WR where irrigation water reduction ranged between 21% up to 28% of that applied to control plants, with or without significant yield reduction or effects on fruit quality parameters depending on the ATs type and concentration. The results indicated that FA at 0.2% gave the maximum reduction in plant WR (28%) and the minimum reduction of P-net (11.13%) and marketable yield (2.3%), consequently WUE was increased by about 33.45% as compared to the untreated plants. Thus, ATS materials can be used to maintain crop yield and increase WUE in the locations where water resources are limited.

Modulation of Brassica napus source–sink physiology through film antitranspirant induced drought tolerance amelioration that is dependent on the stress magnitude

AbstractIncrease in drought conditions during the oilseed rape (OSR) reproductive phase is predicted to occur more often in the temperate zone, leading to significant yield losses. Crop management solutions such as film antitranspirant (AT) applied at key drought‐sensitive growth stages on both wheat and oilseed rape have recently been shown to alleviate drought‐induced yield losses. However, there is a lack of information regarding potential AT effectiveness to reduce drought damage on OSR plants at different soil moisture regimes. Therefore, two similar experiments were performed in a computer‐controlled glasshouse/phenotyping centre to investigate the physiological responses of OSR to well‐watered (WW), moderate water stress (MWS), water stress (WS) and severe water stress (SWS) conditions. Stress treatments were imposed at the initiation of flowering and treated with an AT or water onto the leaf canopy. Stress limited the gas‐exchange and increased leaf temperature, leaf‐to‐air temperature, bud‐to‐air temperature and ABA concentrations which increased with stress intensity in all tissues analysed. Yield components were significantly reduced by WS and SWS treatments when compared to the WW plants. Application of AT counteracted the detrimental effect of WS and SWS by decreasing water use over the first few days of stress application thus improving relative water content and leaf water‐use efficiency, decreasing ABA accumulation in leaf and all the reproductive organs analysed (buds, flowers and pods) and avoiding bud‐to‐air temperature increases. AT application sustained pod formation and seed production under WS but only seed production under SWS conditions. These data suggest that leaf‐canopy application of AT at key phenological stages under particular magnitudes of soil moisture deficit may sustain OSR reproduction and reduce yield losses.

Effect of foliar application of antitranspirant on photosynthesis and water relations of pepper plants under different levels of CO 2 and water stress

Strategies such as foliar application of antitranspirants have the potential to regulate transpiration, but often, the limitation of CO 2 exchange as a result of reduced stomatal conductance can impair this beneficial effect. Elevated ambient [CO 2] could significantly improve CO 2 diffusion while effectively reducing transpiration. In this experiment, we examined the response of sweet pepper ( Capsicum annuum L.) to the foliar application of antitranspirant (AT) under two [CO 2] (380 and 2000 μmol mol −1) and two drought intensities (4 or 8 d without irrigation). The results showed that stomatal conductance and transpiration were reduced, while AT impaired photosynthesis at standard, but not at elevated [CO 2] of fully irrigated plants. This effect was already apparent after 4 d of drought. Drought had a minor impact on chlorophyll fluorescence ( F v/ F m). Additionally, root respiration was increased at elevated [CO 2] but, after 8 d of drought, it was higher for plants treated with AT than for non-sprayed plants. Leaf water potential was affected more by drought at ambient compared to elevated [CO 2], and, especially after 8 d of drought, AT minimized the reductions in leaf water potential. Leaf concentrations of proline and starch were affected by both [CO 2] and AT, especially after 8 d of drought. Moreover, increasing [CO 2] promoted the accumulation of starch, but led to decreases in the tissue concentrations of the soluble organic osmolytes, and hence diminished osmotic adjustment after 8 d of water withholding, relative to ambient [CO 2]. This study indicates that, in addition to the reported beneficial effect of elevated [CO 2] on drought stress, AT could significantly improve drought tolerance in sweet pepper plants.

Effects of Antitranspirant Spray and Potassium: Calcium: Magnesium Ratio on Photosynthesis, Nutrient and Water Uptake, Growth, and Yield of Sweet Pepper

ABSTRACT Sweet pepper plants (Capsicum annuum L.) were cultivated hydroponically under different nutrient cation ratios at both high potassium (K)/calcium (Ca) (12:2) or magnesium (Mg)/Ca (4:2) ratios, compared with half strength Hoagland's solution (K:Ca:Mg; 3.5:2:0.5). Additionally, antitranspirant (Pinolene) was sprayed every fortnight to the aerial part of the plant at 1% (v/v). The antitranspirant (AT) did not affect dry weight accumulation in the leaves, stems, roots, total plant leaf area, or leaf dry weight percentage. Net carbon dioxide (CO2) assimilation was not impaired by the AT but the water uptake was reduced significantly independent of the nutrient solution used. The AT did not affect the cation uptake but high Mg significantly reduced Ca concentration in leaves, stems, and fruits, whilst high K had an effect only in old leaves and fruits. The AT reduced fructose and glucose concentration in the leaves but no effect was found in the fruits. Fruit yield was not affected by AT, but it was increased when plants were grown with high Mg/Ca. The percentage of blossom-end rot was reduced with the AT, whilst it was increased with the solutions having high K/Ca or high Mg/Ca. The AT significantly reduced fruit firmness in high Mg/Ca and control solution but no effect was found for fruit color, shape index, total soluble solids, or pericarp thickness.

USE OF CROP SIMULATION TO EVALUATE ANTITRANSPIRANT EFFECTS ON TOMATO GROWTH AND YIELD

Maximum crop production is closely related to the availability of water. Transpiration may be reduced by theapplication of an antitranspirant (AT) that would increase leaf resistance to diffusion of water vapor. Our objective was todetermine the effectiveness of one of the most promising antitranspirants, Vapor Gard, on tomato production inFlorida. An experiment with three treatments, control plants with no AT application, sprayed with AT only beforeflowering, and sprayed with AT before flowering, at fruit initiation and after first harvest, was conducted at Bradenton,Florida, in 1997. A dynamic, greenhouse tomato, growth and yield model was modified and used to characterize howdifferent plant growth processes are affected by antitranspirant. Parameters in the model were estimated by minimizingsum of squares of error between simulated and observed data for each treatment. Root mean square errors for number ofmain stem nodes, leaf area index, total above ground biomass and fruit dry weight averaged 0.48, 0.17, 35.68g m2, and81.16 g m2, respectively, demonstrating a close fit of the observed data. By using the model, alternate hypotheses todescribe the effects of AT on growth processes were evaluated. It was found that the main effects of AT treatments ontomato plants were on node development and LAI growth, as indicated by differences in model parameters for these twovariables. There was no effect on fruit yield. Most of the vegetative growth response could be explained by an increase inplant temperature likely caused by reduced transpiration by the AT treated plants.

Application of Antitranspirant and Reduced Rate Fungicide Combinations for Fruit Rot Management in Cranberries

Studies were conducted over a 3-year period to evaluate the efficacy of reduced rate combinations of chlorothalonil and an antitranspirant (AT), Wilt-Pruf, for control of fruit rot in cranberries. Several reduced rate combinations provided control comparable to that with the fungicide used alone at suggested label rates of 0.76 to 1.34 liters/ha (4 to 7 pt/A) in field trials. In two trials, higher concentrations of the AT (3 to 5%) had a detrimental effect on total and usable yield at higher fungicide rates. The lowest rate of chlorothalonil that can be effectively used in combination with any tested rate of Wilt-Pruf is 0.76 liters/ha (4 pt/A). Using 0 or 0.38 liters/ha (0 or 2 pt/A) with any tested rate of the AT inadequately protected the berries against fruit rot infection. The incorporation of reduced rate combinations may offer the management advantage of lowered environmental risk per fungicide application in certain situations.

An Improved Method for Acclimatizing Tissue-cultured Walnut Plantlets Using an Antitranspirant

An Improved Method for Acclimatizing Tissue-cultured Walnut Plantlets Using an Antitranspirant

Influence of Crop Load on the Response of Cherry Fruit Growth and Size to Antitranspirant1

Abstract Fruit growth and final size were greater on lightly cropped than on moderately heavily cropped cherry (Prunus avium L. cv. Buriat) trees. A wax-based antitranspirant (AT), sprayed 1 week before harvest, increased fruit size on both lightly and moderately heavily cropped trees. Although the lightly cropped AT-treated trees had the largest fruit at harvest, the response to AT was greatest on the moderately heavily cropped trees. Thus, AT can improve fruit grade-size, and probably monetary returns, particularly on heavily cropped trees. High rates of AT application, however, can adversely affect fruit appearance.

PHREATOPHYTE EVAPOTRANSPIRATION AND ITS POTENTIAL REDUCTION WITHOUT ERADICATION1

ABSTRACT: The continuous availability of ground water to riparian phreatophytic vegetation results in large evapotranspiration (ET) losses in summer. Chemical or physical eradication of this vegetation can have undesirable environmental side effects. Spraying phreatophyte foliage with a nontoxic antitranspirant (AT) may reduce transpiration without eradication. Transpiration rate per unit leaf area was similar for several phreatophyte species, but ET per unit land area of phreatophytes depneds more on stand density than species. The mean ET for saltcedar in June was 8.1 mm/day measured by Bowen ratio, compared with 7.9 mm by lysimeters. ATs and growth‐retardants reduced transpiration by over 50 percent in laboratory tests where foliage was thoroughly sprayed. In the field AT sprayed by a back‐pack mistblower reduced ET by 20–35 percent initially and 10 percent after a month. No ET reduction occurred when AT was sprayed by helicopter on saltcedar, because excessive droplet size and heavy salt deposits on the foliage resulted in poor spray adherence. Wax‐based AT was relatively nontoxic to fish and wildlife. Dissolved oxygen could be reduced for aquatic life, but further AT dilution in streams and ponds would minimize this. Helicopter spraying may affect bird nests and egg hatchability. Although ATs significantly reduce ET, their high cost and spraying difficulties preclude current use on phreatophytes. With improvement they may economically help to conserve water in riparian areas in future years.

Effect of an Antitranspirant on Water Use, Growth, and Yield of Greenhouse-grown Potatoes1

Abstract Treatments of 0, 2% and 4% Folicote in water were applied to runoff at 0, 7 and 16 days after bloom (DAB) on ‘Norgold Russet’ potatoes (Solanum tuberosum L.) grown in the greenhouse. Folicote is a wax emulsion antitranspirant (AT) containing 60% solids. Treatments at 0, 7 and 16 DAB with 2% AT reduced water uptake by >20% for 4, 8, and 14 days respectively, following application. AT treatment at 4% reduced water uptake >40% for 10-14 days. There was no significant reduction of tuber yield even at the higher concentration.

Conserving water by antitranspirant treatment of phreatophytes

A wax‐based antitranspirant (AT) was sprayed on leaves of three phreatophytes, salt cedar (Tamarix sp.), cottonwood (Populus sp.), and willow (Salix sp.), as an alternative to eradicating them to conserve water. Scanning electron micrographs gave information on the nature of the foliar surfaces and coverage by the AT wax. A 10% solution of AT (vol/vol) reduced the transpiration rates of container‐grown phreatophytes by 35–75% 1 day after spraying and by 17–56% after 4 days. In gas exchange studies with salt cedar in the field, transpiration was reduced 40% by a ‘light’ application of 6% AT and 70% by a ‘heavy’ application. The AT also increased resistance to water vapor diffusion and the water potential of the sprayed leaves. On salt cedar, phytotoxicity occurred at high temperature and solar radiation only if spray applications were very heavy. The AT conserved water much more effectively when it was applied to the outer part of the canopy than when it was applied to the inner shaded foliage, where transpiration was already minimal. These data from sprays applied from the ground provided a basis for trials of AT application by aircraft.

Aerial spraying of phreatophytes with antitranspirant

An antitranspirant (AT) can retard excessive groundwater consumption by phreatophytes without eradicating them. To determine whether aerial spraying (the only realistic application method for most sites) of a 6% (vol/vol) wax‐based AT emulsion would provide adequate spray coverage and reduce transpiration, multiple passes were made with (1) a fixed wing plane on salt cedar, cottonwood, and willow and (2) a helicopter on salt cedar. Spray coverage on the ground was 30–100% in the open (depending on the number of passes and wind drift) and 10–90% under the canopies (depending on vegetation density). Average coverage on tags ranged from 13% in the lower canopy to 75% in the upper (depending on species and application rate) after spraying by the fixed wing plane and 47 to 98% after spraying by the helicopter. Coverage in the center of dense bushes was 0–20%, but transpiration is only minimal there. Scanning electron microscope photomicrographs showed considerable AT on foliage in the upper canopy and lesser amounts in the lower; the film was detected even 24 days after spraying. Aerially applied AT increased resistance to leaf water vapor diffusion by 150% during the first few days and by 80% thereafter. Transpiration of outer foliage of salt cedar was reduced 50% initially and 20% after two weeks without phytotoxicity.

Studies of the Mechanism by which Daminozide (B9) Inhibits Stomatal Opening

the mechanism by which the synthetic growth retardant dammozide (?59) inhibits stomatal opening has been investigated, and its action compared with that of the naturally occurring growth hormone, abscisic acid. The inhibition of stomatal opening by low concentrations of daminozide in normal air is largely reversed in C02-free air, suggesting that the main effect is due to an increase in internal CO2 concentration. This is supported by observations of a raised level of CO2 compensation in treated leaves. The C02-independent light reaction of stomata does, however, also appear to be inhibited by daminozide. Higher concentrations cause damage to cells of the epidermis, and such effects could also be found in normal practical use of the growth retardant. The mechanism of action of daminozide on stomata has little in common with that of abscisic acid, which does not operate by increasing the internal CO2 concentration and does not induce cellular damage. Daminozide cannot be recommended for practical use as an antitrans pirant because of its mechanism of action, which is likely to cause a decrease in the efficiency of water use.

Antitranspirant Effects on the Water Status of ‘Manzanillo’ Olive Trees1

Abstract The water balance of both irrigated and unirrigated olive (Olea europaea L. cv. Manzanillo) trees was improved by spraying a film-forming antitranspirant (AT). This was evidenced by increased resistance to water vapor diffusion from the leaves, reduced daytime shrinkage of limbs, and increased leaf and fruit water potential. The improvement in plant water potential by AT was equivalent to the effect of an irrigation. Transpiration at night through incompletely closed stomates, especially when night humidity was low, retarded normal nocturnal rehydration of the olive limbs and fruit. The improved water balance of AT-treated olive trees indicated a potential for increasing fruit growth.

Effect of Growth Regulator and Antitranspirant Chemicals on Water Requirement and Growth Components of Alfalfa (Medicago sativa L.)1

Plants of Medicago sativa L. cult. ‘Mesa‐Sirsa’ were grown in both the greenhouse and controlled environmental growth chambers and used to evaluate the effect ot various antitranspirant and growth regulator chemicals on water requirement and growth components. Gibberellic acid (GA) significantly lowered the water requirement of alfalfa in all environments. Indoleacetic acid (IAA), (2‐chloroethyl) trimethylammonium chloride (CCC), phenylmercuric acetate (PMA), and dodecenylsuccinic acid (DSA) did not alter the water requirement of alfalfa. The antitranspirant chemicals did not reduce the amount of water transpired, and further DSA caused plant damage when used as a foliar spray.Gibberellic acid significantly increased the amount of stem tissue produced in all environments, which resulted in more total dry‐forage yield. Gibberellic acid had no effect on the amount of leaflet tissue produced except in experiments where GA stimulated secondary branching.