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Influence of an inhibitor of gibberellin biosynthesis, paclobutrazol, on apple seed gibberellin content
Author(s) -
Steffens G. L.,
Stafford A. E.,
Lin J. T.
Publication year - 1991
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1991.tb00107.x
Subject(s) - paclobutrazol , gibberellin , malus , high performance liquid chromatography , shoot , horticulture , chemistry , gas chromatography , daminozide , botany , biology , chromatography , plant growth
Tissue‐culture‐propagated own‐rooted cv. Spartan apple trees ( Malus domestica Borkh.) planted in 1979 were treated in 1983 and 1985 via a soil‐line trunk drench with the plant growth retardant paclobutrazol [(2RS, 3RS)‐1‐(4‐chlorophenyl)‐4.4‐dimethyl‐2‐(1,2, 4‐triazol‐1‐yl) pentan‐3‐ol]. Seeds of immature fruits from untreated and treated trees were sampled in 1989 ca 75 days after full bloom. After seeds were freeze‐dried, gibberellins (GAs) were extracted, purified and fractionated via C 18 reversed‐phase high‐performance liquid chromatography (HPLC). Gibberellins A 1 , A 3 , A 4 , A 7 , A 8 , A 9 , A 15 , A 17 , A 19 , A 20 , A 24 , A 34 , A 35 , A 44 , A 51 , A 53 , A 54 , A 61 , A 62 , A 63 and A 68 were identified by using C 18 HPLC, gas chromatography‐selected ion monitoring and Kovats retention indices. Eight of the GAs identified were also quantified by using deuterated internal standards. The paclobutrazol applications caused a 55% reduction of vegetative shoot elongation in 1989, but both treated and untreated trees had developed a biennial bearing pattern by that time (heavy bloom or “on year’in 1989). Levels of early 13‐hydroxylation pathway GAs, viz. GA 53 , GA 19 , GA 20 , GA 1 and also GA 3 , were not altered by treatment. However, GA 4 , GA 7 and GA 9 were increased 13.4, 6.5 and 3.8 times, respectively, in seeds of fruit from treated compared to untreated trees.