Benzyladenine and Gibberellic Acid Application Prevents Abscisic Acid-induced Leaf Chlorosis in Pansy and Viola

Abstract

Drought stress during the shipping and retailing of floriculture crops can reduce postproduction shelf life and marketability. The plant hormone abscisic acid (ABA) mediates drought stress responses by closing stomata and reducing water loss. Applications of exogenous s-ABA effectively reduce water loss and allow a variety of species to survive temporary periods of drought stress. Unfortunately, s-ABA application can also lead to leaf chlorosis, which reduces the overall quality of economically important bedding plant species, including Viola ·wittrockiana (pansy). The goal of this research was to determine how to prevent s-ABA-induced leaf chlorosis in pansy and a closely related species, Viola cornuta (viola). All concentrations of both spray (250 or 500 mgÁL -1 ) and drench (125 or 250 mgÁL -1 ) s-ABA applications induced leaf yellowing. Young plants at the plug stage and 11-cm finished plants with one to two open flowers were further evaluated to determine if the developmental stage of the plants influenced s-ABA effectiveness or the development of negative side effects. Both plugs and finished pansies and violas developed leaf chlorosis after s-ABA applications, but symptoms were generally more severe in finished plants. The individual application of benzyladenine (BA), gibberellic acid (GA 4+7 ), or the ethylene perception inhibitor, 1-methylcyclopropene, before s-ABA application had no effect on the development of s-ABA-induced leaf chlorosis. However, applications of 5 or 10 mgÁL -1 BA and GA 4+7 as a mixture (BA + GA 4+7 ) before a drench or spray application of s-ABA prevented leaf chlorosis. The application of s-ABA and BA + GA 4+7 would allow floriculture crops to tolerate temporary periods of drought stress without any loss of postproduction quality.

Foliar Application of Abscisic Acid Induces Dormancy Responses in Greenhouse-grown Grapevines

“…In fact, Jiang and Zhang (2001) reported that ABA is a promoter of the antioxidant defense system when plants are under oxidative stress, but high ABA concentration (1000 mgÁL -1 ) induced an excessive production of active oxygen species, which led to an oxidative damage to leaves of maize seedlings. Waterland et al (2010) demonstrated that application of S-ABA in bedding plants induced phytotoxicity. It was also suspected that phytotoxicity was associated with the low pH of ABA solutions, which varied from pH = 2.8 for 3200 mgÁL -1 to pH = 3.8 for 200 mgÁL -1 .…”

Effect Of Benzyl Adenine And Gibberellic Acid On The Vegetative Growth And Flowering Of Chrysanthemum Plant

“…Application of benzyl adenine have been shown to have effects on many other physiological and developmental processes, including leaf senescence, leaf chlorosis, increase the vase life, delaying senescence of cut carnation by inhibiting ethylene biosynthesis (Cook et al 1985), nutrient mobilization, apical dominance, the formation and activity of shoot apical meristems, floral development, combating drought stress in plants (Waterland et al 2010).…”

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

“…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).…”

“…Plants were held in the greenhouse under the previously described environmental conditions for subsequent evaluations. Half of plants treated with each antitranspirant had water withheld (waterstressed) until all treated plants reached a visual wilt status rating of 3 or below (unmarketable) as described by Waterland et al (2010c). Wilt status ratings were from 1 to 5 with 5 = completely turgid, 4 = soft to the touch but still upright, 3 = starting to wilt, 2 = severely wilted, and 1 = wilted to the point that leaves are dried and desiccated (Waterland et al, 2010a).…”

“…Evaluation continued until all plants reached a visual wilt status rating of 3 or below. The shelf life of waterstressed plants was calculated as the number of days from the initiation of water being withheld until plants reached a wilt status rating of 3 (Waterland et al, 2010c).…”