Abscisic acid increases in non‐growing and paclobutrazol‐treated fruits of seedless mandarins

Abstract

Clementine (Citrus reticulata [Hort.] Ex. Tanaka cv. Oroval) is a self‐incompatible mandarin with a slow rate of fruit growth and high percentage of fruit abscission. Seedless Satsuma (Citrus unshiu [Mak] Marc. cv. Clausellina) shows natural parthenocarpy and higher fruit set. Application of 25 μg fruit−1 of paclobutrazol (PP333), an inhibitor of gibberellin biosynthesis, reduced the rate of growth and accelerated fruit abscission in both varieties. In contrast, gibberellin A3 (GA3) stimulated fruit growth only in the self‐incompatible mandarin. Clementine fruits, in the absence of pollination, showed an approximately 2‐fold transient increase in the free abscisic acid (ABA) content shortly after petal fall. In Satsuma, a very small accumulation of ABA was detected. Paclobutrazol treatment induced a 3‐fold increase in ABA in Satsuma fruits but did not substantially affect the pattern of ABA accumulation in Clementine. In this variety, GA3 suppressed the ABA increase observed in untreated fruits. These effects were observed 24 h after treatment. However, in Satsuma fruits, the effect of GA3 on the ABA content was negligible. In addition, a comparative analysis of growing and non‐growing fruits of Clementine showed that ABA, on a per unit weight basis, was always higher in the non‐growing fruits. Treatment with 85 μM fluridone, an inhibitor of carotenoid biosynthesis and thus indirectly of ABA, delayed fruit abscission in Clementine, but also decreased fruit growth. Collectively, these observations indicate a relationship between high ABA content and a reduced rate of fruit growth and an acceleration of fruit abscission.

Endogenous gibberellins and abscisic acid-metabolites: their role for during flower bud abscission and embryo development in pistachio

“…Similar to these findings, many researchers reported that ABA was required for embryo growth during the early phase of flower and seed development (Goldschmidt 1980;Cheng et al, 2002;Frey et al, 2004), but high ABA levels in later developmental phases inhibited embryo growth by suppressing gibberellin signaling (White et al, 2000;Raz et al, 2001) and abscission was directly controlled by phytohormones (Addicott 1983). ABA has also been implicated in the abscission of young fruit trees, such as citrus (Sagee and Erner 1991;ZacarõÂas et al, 1995;GoÂmez-Cadenas et al, 2000) and apple (Vernieri et al 1992). These findings are also consistent with previous studies in terms of plant growth regulating functions synthesized in plants and growth periods of fruit species (Talon et al, 1990;Westwood, 1993Zacarias et al, 1995Okay et al, 2011).…”

“…ABA was first isolated from the mature flowers of cotton, rose, peas, and fruit as an abscission accelerator (Lui and Carns 1961;Mayak et al, 1972;Ehuwens and Schwabe, 1975). Some researchers have suggested that alternate bearing was probably to be determined in abscission which effect separately and in combinations with ABA and GAs (ZacarõÂas et al 1995;Mehouachi et al, 1996;Talon et al, 1997;GoÂmez-Cadenas et al, 2000;Baktır et al, 2004;Ulger et al, 2004;Okay et al, 2011). These reports described the determination of ABA and GAs activity in different plant organs (Tables 2-5; Figures 1-4).…”

Gibberellic acid and norflurazon affecting the time-course of flavedo pigment and abscisic acid content in ‘Valencia’ sweet orange

“…Quantification of ABA was performed by indirect enzyme-linked immunosorbent assay (ELISA) as reported by Zacarías et al (1995) and Lafuente et al (1997). ABA was extracted from 200 mg of fresh tissue, with acetone (80%) containing citric acid 2.5 mM and butylated hydroxytoluene 4.5 mM, and stored overnight at 4 • C, in darkness.…”

Growth and physiological responses of grape (Vitis vinifera “Combier”) to excess zinc

“…The extracted solution was dried in vacuo at 30°C. The dried residues were dissolved in 1 mL of the extracted solution, and approximately 100 lL was analyzed for ABA by ELISA using assay kits (made by China Agricultural University), according to the manufacturer's instructions and that described by Zacarias et al (1995). Lipid peroxidation was measured by equivalents of MDA contents.…”