Film-forming Antitranspirants Research Articles

Canopy application of film antitranspirants over the reproductive phase enhances yield and yield-related physiological traits of water-stressed oilseed rape (Brassica napus)

Oilseed rape (Brassica napus L.) yield is strongly decreased by water deficit, and crop-management solutions are urgently required considering the emerging difficulties in breeding for drought-tolerant varieties. Film-forming antitranspirants (polymers) are agrochemicals that, applied to the crop canopy, mechanically block the stomata and decrease canopy transpiration. In this study, the drought-protection efficacy of an adaxial-surface application at the flowering stage of two film-forming treatments (poly-1-p-menthene and di-1-p-menthene) was investigated in pot-grown, droughted oilseed rape over two glasshouse experiments. Over the drought period, the two compounds reduced leaf stomatal conductance (P < 0.001), and as the soil moisture deficit increased, they sustained carbon assimilation and improved water-use efficiency with differing efficacy. Following the antitranspirant treatments, ABA concentration in leaves and reproductive organs was severely reduced and this was accompanied by significant improvements in leaf and flower–pod water potential. Drought significantly decreased the seed dry matter production of oilseed rape plants, by 39% on average. The treatments significantly increased seed dry matter by 13% (poly-1-p-menthene) and 17% (di-1-p-menthene), on average, compared with the unsprayed droughted plants, as a result of a significant increase in number of pods per plant, by 11% and 13%, respectively. The results suggest that film-forming compounds may be a useful crop-management tool to avoid severe drought-induced yield losses in oilseed rape by improving water-use efficiency and plant water status, thus alleviating ABA signalling under water deficit.

Film antitranspirants increase yield in drought stressed wheat plants by maintaining high grain number

We investigated the use of film-forming antitranspirants (AT) to reduce transpiration and alleviate the adverse effects of late-season drought on wheat (Triticum aestivum L.) growth and yield. Two experiments were conducted in a controlled-temperature glasshouse from April to November 2014, to compare two watering regimes (well watered and water deficit) and three AT treatments (unsprayed control, sprayed before boot swollen and sprayed before anthesis complete). We measured plant water use, transpiration rate, stomatal conductance and photosynthesis. Relative leaf turgor was measured in real time using a non-destructive method of leaf patch clamp pressure. Drought stress reduced daily water use, transpiration rate, stomatal conductance and leaf turgor in wheat plants after about four days. In contrast, these measurements rapidly declined soon after AT application in both well-watered and water-deficit plants. Nevertheless, once soil moisture deficit increased markedly, AT-treated water-deficit plants maintained significantly higher levels of photosynthesis than untreated plants. Drought stress reduced grain yield in unsprayed control plants by more than 40%, compared to well-watered control plants, mainly due to fewer grains per spike. In contrast, drought stress with AT application prior to the most drought-sensitive boot stage reduced yield by only 14%. These results suggest that AT has the potential to improve wheat yields with late-season drought, as is common in semiarid regions; although, more research is required to test the wider applicability of these results in field conditions.

Effects of ABA, antitranspirants, heat and drought stress on plant growth, physiology and water status of artichoke transplants

In semiarid regions of the U.S., artichoke [Cynara cardunculus L. var. scolymus (L.) Fiori] seedlings planted in the field during late summer or early fall generally experience simultaneous high air temperatures and short drought episodes causing transplant shock and delay in root and shoot development. This experiment was conducted to determine the effects of heat (35/20°C, day/night temperature regimes vs. 25/10°C) and drought (30% water holding capacity vs. 60%) stresses on plant growth, physiology and water status of artichoke cv. ‘Green Globe Improved’ transplants during 14 days after transplanting (DAT). Heat stress significantly inhibited shoot but not root growth 14 DAT. In contrast, drought stress significantly inhibited root growth between 7 and 14 DAT. Transpiration (E), stomatal conductance (gs) and photosynthetic rate (ACO2) decreased by transplanting (within 24h) regardless of treatments. Thereafter, E and ACO2 significantly increased by heat compared to 25/10°C temperature regime 3 DAT. However as heat stress progressed E, gsACO2 and leaf water potential were reduced. Drought stress sharply reduced E, gs and ACO2 within 1 DAT and leaf water status as early as 3 DAT. The combination of heat and drought stress significantly reduced shoot and root growth 7 and 3 DAT, respectively. This suggests that to prevent transplant shock by heat and drought it is desirable to prevent leaf dehydration. Thus, consecutive greenhouse experiments were also conducted to evaluate the effects of three film-forming antitranspirants (Antistress, Transfilm and Vapor Gard) and abscisic acid (ABA: 0, 500, 1000, and 2000mgL−1) foliar application on physiological responses and shoot water status of artichoke transplants exposed to drought stress (water withholding). ABA at 1000mgL−1 enhanced drought tolerance of transplants, a response that was associated with the maintenance of shoot water status via stomatal closure. Film-forming antitranspirants were not effective to mitigate drought stress. These results suggest that exogenous ABA could be a useful plant growth regulator to condition artichoke transplants to withstand temporal drought stress conditions and reduce transplant shock.

Antitranspirant Treatments of Stock Plants do not alter Growth and Adventitious Rooting of Shoots of ‘Montaigne’ Lilac and White Fringetree

Abstract Antitranspirants were evaluated for their effectiveness as a stock plant treatment to improve adventitious rooting of softwood cuttings of Syringa vulgaris L. ‘Montaigne’ (Montaigne lilac) and Chionanthus virginicus L. (white fringe tree). New shoots of S. vulgaris ‘Montaigne’ and C. virginicus were sprayed with one of two film-forming antitranspirants including Clear Spray® (aqueous acrylic emulsion) and sodium silicate; or Atrazine®, a herbicide that acts as a stomate-regulating antitranspirant. Shoot caliper of antitranspirant-treated lilacs increased more slowly than controls. Thirty days after treatment cuttings were taken from both taxa. All treatments resulted in 80 to 85% rooting of cuttings in lilac after 6 weeks, but cuttings from Clear Spray®-treated plants rooted more quickly. Chionanthus virginicus cuttings treated with Clear Spray® had significantly lower rooting (16%) than cuttings taken from Atrazine® treated plants (50%). In a subsequent experiment, antitranspirant treatment had no significant effect on shoot length or caliper of ‘Montaigne’ lilac. Photosynthetic rate, transpiration rate, and location of cutting on the stock plant were all positively correlated with shoot length, shoot caliper, and cutting diameter. Shoot length and caliper and cutting diameter, however, were all negatively correlated with root number and root length. There were no significant treatment effects on rooting percentage, root number or root length.

548 Antitranspirant Treatments Affect Stock Plant Growth and Rooting Percentage in Two Members of the Oleaceae Family

Syringa vulgaris L. `Montaigne' (French hybrid lilac) and Chionanthus virginicus L. (white fringetree) stock plants were sprayed with two film-forming antitranspirants, Clear Spray and sodium silicate, and one stomate-regulating antitranspirant, atrazine. After 30 days of growth, cuttings were taken from both species. Shoot calipers of antitranspirant-treated lilacs increased at a slower rate than the control lilacs. There were no long-term shoot length changes in lilac due to antitranspirant treatments. Shoots of Clear Spray-treated fringetrees increased in length significantly less than other treatments. Rooting was evaluated once a week from week 3 until 6 weeks after cuttings were taken for lilac and every 2 weeks from week 6 to 12 weeks after sticking for fringetree. All treatments resulted in 80% to 85% rooting in lilac after 6 weeks, but Clear Spray-treated plants rooted more quickly. Fringetree cuttings treated with Clear Spray had a significantly lower rooting percentage (15%) than the other treatments (35% to 50%).

Antidesiccants Applied to Packaged Rose Plants Affect Growth and Field Performance

Moisture loss from bare-root plants during postharvest handling and storage can have a significant impact on plant survival and growth during establishment. Three film-forming antitranspirants and hot wax were applied to bare-root roses (Rosa) packaged after harvesting from the field and before 13 weeks of –2C storage to determine effects on vegetative growth and flowering. Subsequently, during 15 days under simulated display conditions (22 to 32C), plants treated with hot wax resumed growth at the fastest rate compared to control or antitranspirant treatments. Hot-wax-treated plants remained at an advanced phenological stage compared to the other plants for 2 weeks following transplanting in the field. For the remaining 10 weeks of the experiment, vegetative growth and flowering development were similar for all treatments. More than 60% of the plants treated with hot wax developed moderate to severe cane damage and plant dieback. Less than 20% of the antitranspirant-treated plants were damaged. A laboratory experiment confirmed that hot wax treatment was most effective; it reduced weight loss from stem sections by 85% relative to the control. The other antitranspirants reduced weight loss by 27%.

859 PB 440 ANTIDESICCANTS APPLIED TO PACKAGED ROSE PLANTS AFFECT GROWTH AND FIELD PERFORMANCE

Moisture loss from bare-root plants during postharvest handling and storage can have a significant effect on plant growth and survival during establishment. Three film-forming antitranspirants and hot wax were applied to bare-root roses packaged after harvesting from the field and before three months of cold storage to determine effects on vegetative growth and flowering. Subsequently, during three weeks under display conditions, plants treated with hot wax resumed growth at the fastest rate compared to control or antitranspirant treatments. Hot wax-treated plants continued to grow at a faster rate than the other plants for two weeks following transplanting in the field. For the remaining 10 weeks of the experiment no differences in vegetative growth or flowering development were found between treatments. Over 70% of the plants treated with hot wax became sunburned, resulting in severe cane damage and plant dieback. Less than 20% of the plants from the other treatments were damaged.

Effect of Film-Forming Compounds on the Development of Leaf Rust on Wheat Seedlings

The effect of film-forming antitranspirants and glues on the development of leaf rust (caused by Puccinia recondita f. sp. tritici) was assessed on wheat seedlings (Triticum aestivum «Ceeon»). When applied before rust inoculation, the compounds Bio-Film, Folicote, and Vapor Gard markedly reduced the number of pustules per square centimeter. Postinoculation application had a significantly smaller effect on suppression of rust development (.)

THE EFFECTS OF FILM-FORMING ANTITRANSPIRANTS ON LEAF WATER RELATIONS OF BEDDING PLANTS

The effectiveness of antitranspirant type and concentration on the leaf water relations of Saliva splendens F. `Firebird and Petunia × hybrida Juss. `Comanche'. Two film-forming antitranspirants, Cloud Cover and Folicote, were tested at three different concentrations in two different environments. The leaf water potential, stomatal conductance, and relative water content were evaluated. Transpiration per unit vapor pressure deficit and stomatal conductance for both crops decrease slightly but there was no trend with respect to the film type, environment or concentration rate. The leaf water potentials and relative water content did not show significant difference after antitranspirant application. In order for antitranspirant application to be of benefit to the growth of herbaceous plants, a more durable coating that remains semipermeable would have to be utilized.

Water Relations of Container-grown Woody and Herbaceous Plants Following Antitranspirant Sprays

Four film-forming antitranspirants, Vapor Gard, Envy, Wilt-Pruf, and Folicote, and a new metabolic antitranspirant UC86177 were applied to container-grown Ulmus parvifolia Jacq. (Chinese elm), Malus sargentii Rehd. (Sargent's crabapple), Viburnum plicatum tomentosum Thunb. (doubleflle viburnum), Lycopersicon esculentum Mill. `Early Giant' (tomato), Petunia × hybrids Hort. Vilm-Andr. `Royal Pearls' (petunia), and Impatiens wallerana Hook. f. `Blitz Orange' (impatiens) plants. Water status was assessed by the following methods: transpiration as water loss per unit leaf area, wilt by visual evaluation, and xylem pressure potential (XPP) determined with a pressure chamber. Antitranspirant treatment had no beneficial effect on water status of doublefile viburnum. In comparison to control plants, results of wilt ratings, XPP, and transpiration measurements for the elm, crabapple, tomato, petunia, and impatiens plants can be summarized as follows: UC86177-treated plants showed significantly less stress in 11 measures and were not different once; Wilt-Pruf was beneficial 10 times and not different twice; Folicote was beneficial nine times and not different three times; Vapor Gard produced eight beneficial results and four similar results; and Envy was beneficial three times and no different nine times. Species differences in response to antitranspirants as well as differences in product efficacy were demonstrated. UC86177 antitranspirant was shown to be as or more effective in controlling water status than the film-forming antitranspirants and may have potential for protecting various plant species against water stress.

The Potential Use of Antitranspirants in the Greenhouse Production of Chrysanthemum1

Abstract Three film-forming antitranspirants were applied to potted chrysanthemums (Chrysanthemum morifolium Ramat.) under greenhouse conditions from the time of potting rooted cuttings to saleable size. Folicote (a hydrocarbon wax emulsion of essentially fully refined paraffin) reduced water loss by an average of 39% and by as much as 65%, but generally detracted from plant appearance, delayed flowering, depressed fresh and dry weight, decreased flower size, increased height and reduced leaf area. While Clear Spray (a lateral based emulsion of undefined composition) and Wilt Pruf NCF (whose active ingredient is a polyterpene compound, Pinolene) reduced water loss 8 and 11% respectively, their side effects were less deleterious and, in a few cases, beneficial. Effects of antitranspirants under summer greenhouse conditions appeared to be of a greater magnitude than during a cooler season of the year.

Effects of film-forming and silicone antitranspirants on four herbaceous plant species

Effectiveness of antitranspirants in reducing transpiration was studied in the laboratory in an attempt to evaluate their potential for conservation and reallocation of soil moisture. Film-forming antitranspirants caused about a 50% reduction of transpiration and photosynthesis in all species. Effectiveness decayed slowly over 10–14 days. Effectiveness of the silicone antitranspirant was very short-lived. Water use efficiency was slightly improved following film-forming antitranspirant treatment of three species. Mixing antitranspirants altered their effects.

Effect of Applied Abscisic Acid and Silicone on Water Relations and Photosynthesis of Woody Plants

Fraxinusamericana and Pinusresinosa seedlings were treated with 7.5% silicone or 10−4 M ABA. Plants were watered on the day following treatment and then subjected to a soil drying cycle. At frequent intervals after the compounds were applied, transpiration, net photosynthesis, leaf water potential, and soil moisture percentage were determined for treated and control plants. Transpiration and photosynthesis of control plants decreased as the soil dried. Silicone was more effective than ABA in reducing water loss of both species, and was much more effective on Pinus than on Fraxinus. Although silicone had a very positive effect on the water potential of Pinus, photosynthesis of treated plants was greatly reduced with rates of treated plants never exceeding those of control plants. As the drying cycle progressed rates of photosynthesis were higher in ABA-treated Pinus plants than in controls. ABA also significantly increased plant water potential and soil moisture percentage. In Fraxinus, as the drying cycle progressed, both ABA- and silicone-treated plants had lower water stresses than untreated plants. Rates of photosynthesis were higher than in untreated plants. The data indicated that film-forming antitranspirants may be unsuitable for use with some gymnosperms, and that compounds which very significantly decrease transpiration are not necessarily useful and practical in the long term.

Antitranspirants for Conservation of Leaf Water Potential of Transplanted Citrus Trees1

Abstract Spraying 7-year-old citrus trees with film-forming antitranspirants before transplanting increased leaf water potential, thereby reducing “transplant shock.” Leaf water potential decreased rapidly after transplanting, by as much as 21 atm in unsprayed, and as little as 6 atm in sprayed trees. There was little benefit from transplanting in late afternoon rather than the morning.