Effects of Abscisic Acid and Benzyladenine on Fruits of Normal and rin Mutant Tomatoes

Abstract

Since ethylene application did not induce ripening in detached fruits of the nonripening mutant rin we initiated studies to determine possible involvement of other hormones. We proposed that the lack of ripening in mutant rin tomato fruit may result from a lack of abscisic acid or from excessive endogenous levels of cytokinin. Application of abscisic acid (3 X cultivar. These same investigators were able to alter the morphology of this mutant to a normal appearance of ABA application (4).This study was conducted to determine whether ABA applications would enhance ripening of normal fruit, and to ascertain whether ABA application might induce a normal ripening pattern in fruit ofthe rin mutant. Secondarily, we wanted to know whether the application of cytokinins might result in inhibition of the ripening pattern of normal tomato fruit, according to the suggestion of Varga and Bruinsma (11). MATERIALS AND METHODSUniform populations of fruits of Rutgers (Lycopersicon esculentum Mill.) and of a partially isogenic strain of rin were produced in a greenhouse as described previously (2, 6). Fruits were harvested at 80% of development. The upper layers of tissue of each stem scar were carefuly removed with a scalpel. The fruits were then transferred to a jar in which 1 ml of solution per 100 g fresh weight of fruit was infiltrated under a vacuum of about 160 mm Hg.A racemic mixture of cis , tratis-and trans, trans-ABA (Burdick Laboratories, Muskegon, Mich.) was applied at 3 x 10-s M and 10-1 M in 0.1 % (v/v) aqueous methanol. The control solution was 0.1 %lo aqueous methanol.BA at 4.44 X 10-4 M was prepared by autoclaving in distilled H20. Concentrations of 1.8 x 10-4 M, 4.44 X 10-M and 4.44 X 10-6 M BA were applied to the fruit. Autoclaved distilled H20 was used as a control.Each treatment was replicated five times. CO2 and ethylene evolution rates were measured daily (7). The time of first red color appearance was also noted for each fruit.Leaf senescence was measured as the rate of Chl breakdown in 7-mm diameter leaf disks taken from the tip leaflet of the newest fully expanded leaf. All procedures were carried out under sterile conditions. Each treatment contained 12 disks which were incubated in the dark at 22 C. Chl was extracted at 6 days after detachment by placing 2 disks into 5 ml of dimethylformamide. Each extraction was replicated 6 times. RESULTSABA at 3 x 10-5 and 10-s M reduced the time to initiate ripening in Rutgers fruit by about 50%7 as indicated by the onset of the respiratory climacteric and the associated rise in ethylene production and the development of red color (Fig. 1). Treatment with ABA also tended to increase the maximum rates of CO2 and ethylene production during ripening but these noted differences were not significant. Treatment of rin fruits with ABA did not significantly alter the rates of either CO2 or ethylene production or cause any changes in color (Fig. 2). BA treatment did not effect any significant changes in the time to the onset of ripening or the rates of CO2 and et...

Influence of Plant Hormones on Ethylene Production in Apple, Tomato, and Avocado Slices during Maturation and Senescence

“…The solutions contained 0.1 mm IAA, IPA,2 GA3, ABA, a combination of IAA and IPA, or a combination of IAA, IPA, and GA3. The concentrations of hormones used were in line with those used with fruit tissues in other studies (4,11). Each incubation flask contained four apple slices (about 1 g), 5 ml solution, and a vial of 20% KOH to absorb CO2.…”

“…The fact that IPA is most effective in the 12-to 24-hr period of incubation, when senescence is rapidly accelerating, further suggests the antisenescence activity of IPA. Cytokinins have been shown to oppose aging in leaf tissues by preserving protein synthesis and Chl (12); in tomato fruit without influencing ethylene production (11); and in banana even in the presence of ethylene (15). The evidence for considering ethylene the causative agent in fruit ripening has been documented by Burg (1).…”

Ethylene control of fruit ripening: revisiting the complex network of transcriptional regulation

“…It has long been considered that other plant hormones besides ethylene are likely required for climacteric fruit ripening (Dostal and Leopold, 1967;Frenkel and Dyck, 1973;Mizrahi et al, 1975;Fan et al, 1998). ABA is known to promote ripening, whereas auxin seems to have an antagonistic effect (Frenkel and Dyck, 1973;Mizrahi et al, 1975;Zhang et al, 2009;Su et al, 2015).…”

“…ABA is known to promote ripening, whereas auxin seems to have an antagonistic effect (Frenkel and Dyck, 1973;Mizrahi et al, 1975;Zhang et al, 2009;Su et al, 2015). The expression of ACS2, ACS4, and ACO1 genes is induced by exogenous ABA, revealing an ABA/ ethylene interplay operating at the level of ethylene biosynthesis (Chernys and Zeevaart, 2000;Jiang et al, 2000;Zhang et al, 2009).…”

Pigments in Vegetables

“…Application of abscisic acid to detached Rudgers tomatoes reduced by about 50010 the time to initiate ripening, as indicated by red color development (Mizrahi et al, 1978).…”