Effects of Short-term Water Stress, Hydrophilic Polymer Amendment, and Antitranspirant on Stomatal Status, Transpiration, Water loss, and Growth in `Better Boy' Tomato Plants

Abstract

<jats:p>Seedling plugs of `Better Boy' tomato plants (<jats:italic>Lycopersicon esculentum</jats:italic> Mill.) were potted in 60% processed fiber: 40% perlite (by volume) media amended or nonamended with either crystalline or powdered hydrophilic polymer (2.4 kg·m<jats:sup>-3</jats:sup>), and treated with one of several concentrations (0%, 2.5%, 5%, 7.5%, and 10%) of antitranspirant GLK-8924, at the four true-leaf stage. Plants were either well-irrigated or subjected to short-term water stress, withholding water for 3 days, after antitranspirant GLK-8924 application. Leaf stomatal conductance, transpiration rate, whole-plant transpirational water loss, and growth were depressed by short-term water stress and antitranspirant GLK-8924. In contrast, hydrophilic polymer amendment increased plant growth, resulting in higher transpirational water loss. The depression of stomatal conductance and transpiration rate by short-term water stress was reversed completely in 2 days after rewatering while the reduction of plant growth rate diminished immediately. The effects of antitranspirant GLK-8924 were nearly proportional to its concentration and lasted 8 days on stomatal conductance and transpiration rate, 4 days on plant growth rate, and throughout the experimental period on plant height and transpirational water loss. Plant growth was reduced by antitranspirant GLK-8924 possibly by closing leaf stomata. In contrast, hydrophilic polymer amendment resulted in larger plants by factors other than influences attributed to stomatal status. Hydrophilic polymer amendment did not interact with antitranspirant GLK-8924 on all variables measured. The application of antitranspirant GLK-8924 was demonstrated to be useful for regulating plant water status, plant growth, and protecting plants from short-term water stress.</jats:p>

Effects of antitranspirant and leaching on medium solution osmotic potential, leaf stomatal status, transpiration, abscisic acid content and plant growth in ’Early Girl’ tomato plants (Lycopersicon esculentum)

“…This study demonstrated that antitranspirant GLK-8924 induces stomatal closure temporarily by exposing the root system of plants to osmotic stress when the water supply in the medium is adequate and confirmed previous reports on the temporary effectiveness of antitranspirant GLK-8924 in reducing transpirational water loss (Gu et al, 1996) without detrimental effects to the plant appearance. The antitranspirant GLK-8924 and the reduced osmotic stress did not alter leaf ABA levels.…”

“…All leaves were excised separately The Journal of Horticultural Science and Biotechnology 1998.73:473-477. spirant GLK-8924 induces stomatal closure by exposing plants to osmotic stress for a short period of time. The effect of antitranspirant GLK-8924 on leaf stomatal status and transpiration was similar to short-term water stress (Gu et al, 1996). However, there are significant differences between the effect of water stress and that of antitranspirant GLK-8924 per se.…”

“…Water stress stimulates abscisic acid (ABA) biosynthesis and ABA releases from site of synthesis to the site of action (Hartung and Davies, 1993). The similarity in the effects observed between antitranspirant GLK-8924 and short-term water stress (Gu et al, 1996) suggests that the effect of antitranspirant GLK-8924 on stomatal closure may be due to the induction of ABA. Stomatal closure has been induced by leaf applications of ABA, a naturally occurring growth inhibitor (Jones and Mansfield, 1970;Kriedemann et al, 1972).…”

“…USA), a naturally occurring product, reduced leaf stomatal conductance (gs), plant transpiration (E), and growth in tomato plants. The effects of antitranspirant GLK-8924 were nearly proportional to its concentration (Gu et al, 1996).…”

“…Transpirational water loss may be reduced by either covering the stomata with film-forming antitranspirants or inducing stomatal closure with metabolic antitranspirants (Gu et al, 1996;Waisel et al, 1969;Walker and Zelitch, 1963). Antitranspirant GLK-8924 (Great Lakes Chemical Co., West Lafayette, Ind.…”