Determining the Effects of Abscisic Acid Drenches on Evapotranspiration and Leaf Gas Exchange of Tomato

Abstract

<jats:p>It is common for plants in the retail market to receive inadequate water and lose aesthetic value within a short period of time. The plant hormone abscisic acid (ABA) is naturally produced in response to drought conditions and reduces transpiration (E) by closing the stomata. Thus, ABA may lengthen shelf life of retail plants by reducing water loss. Two studies were conducted to look at effects of ABA on plant water use and shelf life over a 13-day period and short-term effects of ABA on leaf physiology. The objective of the short-term study was to determine how quickly 100-mL drenches of 250 mg·L<jats:sup>−1</jats:sup> ABA solution affect leaf gas exchange of tomatoes (<jats:italic>Solanum lycopersicum</jats:italic> ‘Supersweet 100’). ABA drenches reduced stomatal conductance (<jats:italic>g</jats:italic><jats:sub>S</jats:sub>), E, and photosynthetic rate (P<jats:sub>n</jats:sub>) within 60 min. After 2 h, E, <jats:italic>g</jats:italic><jats:sub>s</jats:sub>, and P<jats:sub>n</jats:sub> were reduced by 66%, 72%, and 55% respectively, compared with the control plants. In the13-day study, ABA was applied to tomatoes as a 100-mL drench at concentrations ranging from 0 to 1000 mg·L<jats:sup>−1</jats:sup> and ABA effects on water use and time to wilting were quantified. Half of the plants were not watered after ABA application, whereas the other plants were watered as needed. In general, higher ABA concentrations resulted in less water use by both well-watered and unwatered plants. ABA delayed wilting of unwatered plants by 2 to 8 days (dependent on the dose) as compared with control plants. In well-watered plants, ABA reduced daily evapotranspiration (ET) for 5 days, after which there were no further ABA effects. Negative side effects of the ABA application were rate-dependent chlorosis of the lower leaves followed by leaf abscission. These studies demonstrate that ABA drenches rapidly close stomata, limit transpirational water loss, and can extend the shelf life of retail plants by up to 8 days, which exemplifies its potential as a commercially applied plant growth regulator.</jats:p>

The ABA signal transduction mechanism in commercial crops: learning from Arabidopsis

“…Application of exogenous ABA to tomato plants caused rapid closure of stomata, limited transpiration and water loss, and extended shelf life of the fruit. However, it also caused chlorosis of the lower leaves followed by leaf abscission (Astacio and van Iersel 2011).…”

Evaluation of Antitranspirants for Enhancing Temporary Water Stress Tolerance in Bedding Plants

“…1 and 2). A rapid reduction of g S resulting from application of antitranspirants helped to maintain a high water status under water stress and thus improved water stress tolerance (Astacio and van Iersel, 2011;Kim and van Iersel, 2011;Shinohara and Leskovar, 2014;Waterland et al, 2010b). Additionally, Anderson and Kreith (1978) reported that bP treatment resulted in initial reduction of transpiration rate by reducing g S of sweetclover (Melilotus officinalis) leaves.…”

“…On the other hand, s-ABA caused chlorosis on the margin of leaves in impatiens. Foliar chlorosis and leaf abscission have been frequently mentioned as side effects of ABA application (Agehara and Leskovar, 2012;Astacio and van Iersel, 2011;Kim and van Iersel, 2011;Waterland et al, 2010aWaterland et al, , 2010cWeaver and van Iersel, 2014). Chlorosis has been known to accelerate with increasing ABA concentration (Agehara and Leskovar, 2012;Astacio and van Iersel, 2011;Weaver and van Iersel, 2014).…”

“…These compounds may contain ABA or other chemicals that increase the ABA concentration in plants (Waterland et al, 2010b). Exogenous application of ABA has enhanced water stress tolerance in various horticultural crops (Agehara and Leskovar, 2012;Astacio and van Iersel, 2011;Goreta et al, 2007;Shinohara and Leskovar, 2014). Goreta et al (2007) found that foliar application of ABA enhanced water deficit tolerance of pepper, which was attributed to decreased g S and increased leaf water potential.…”

Effect of abscisic acid on the calcium content for controlling blossom-end rot in tomato under water stress

“…The 100 % of ETc and deionised water were set as a control treatments. The concentration of 500 mgL -1 of ABA was chosen based on Astacio & Van Iersel (2011).…”