Suejin Park, Sarah Mills, Youyoun Moon
Aug 1, 2016
S UMMARY . Water stress during shipping and retailing reduces the postproduction quality and marketability of bedding plants. Antitranspirants can temporarily prevent plants from wilting by either physically blocking stomata or physiolog- ically inducing stomatal closure, limiting transpirational water loss from leaves. The goal of this research was to evaluate the efﬁcacy of commercially available antitranspirants on enhancing temporary water stress tolerance in bedding plants. Two physical antitranspirants [ b -pinene polymer ( b P) and vinyl-acrylic polymer (VP)], and three physiological antitranspirants [two sugar alcohol- based compounds (SACs) and a biologically active form of abscisic acid (s-ABA)] were applied to begonia ( Begonia semperﬂorens-cultorum ), new guinea impatiens ( Impatiens hawkeri ), impatiens ( Impatiens walleriana ), petunia ( Petunia · hybrida ), african marigold ( Tagetes erecta ), and french marigold ( Tagetes patula ). Physical antitranspirants were sprayed on foliage and physiological antitrans- pirants were drenched to the media. All antitranspirants were applied at half (0.5 · ), equal to (1 · ), or twice (2 · ) the manufacturer’s recommended rate. Extended shelf life was observed when b P or s-ABA was applied. Treatment with b P increased the shelf life of impatiens and african marigold by 1 and 1.3 days compared with control plants, respectively. The application of b P at 2 · was more effective at delaying visual wilting than at lower rates (0.5 · and 1 · ) in african marigold. Applications of s-ABA delayed wilting by 1.3 to 3.7 days in all tested cultivars. The shelf lives of impatiens and petunia treated with s-ABA at 2 · were extended the most by 3.7 and 3.0 days compared with control plants, respectively. A rapid reduction of stomatal conductance ( g S ) was observed within 4 hours of b P or s-ABA application in plants showing delayed wilting symptoms. s-ABA treatment appeared to cause marginal leaf chlorosis in impatiens, whereas application of b P damaged the opened ﬂowers in all tested cultivars. The application of VP or SACs did not extend shelf life in any treated plants. These results suggest that foliar application of b P on selected species and treatment with s-ABA on most of species would allow bedding plants to withstand water deﬁcit during shipping and/or retailing.