Gibberellins in developing fruits ofPisum sativumcv. Alaska: Studies on their role in pod growth and seed development

✍ Scribed by J. L. Garcia-Martinez; V. M. Sponsel; P. Gaskin

• Book ID: 104753031
• Publisher: Springer-Verlag
• Year: 1987
• Tongue: English
• Weight: 780 KB
• Volume: 170
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00392389

✦ Synopsis

Gibberellins A1, As, A2o and A29 were identified by capillary gas chromatography-mass spectrometry in the pods and seeds from 5-d-old pollinated ovaries of pea (Pisum sativum cv. Alaska). These gibberellins were also identified in 4-d-old non-developing, parthenocarpic and pollinated ovaries. The level of gibberellin A1 within these ovary types was correlated with pod size. Gibberellin At, applied to emasculated ovaries cultured in vitro, was three to five times more active than gibberellin A2o. Using pollinated ovary explants cultured in vitro, the effects of inhibitors of gibberellin biosynthesis on pod growth and seed development were examined. The inhibitors retarded pod growth during the first 7 d after anthesis, and this inhibition was reversed by simultaneous application of gibberellin Aa. In contrast, the inhibitors, when supplied to 4-d-old pollinated ovaries for 16 d, had little effect on seed fresh weight although they reduced the levels of endogenous gibberellins A~o and A29 in the enlarging seeds to almost zero. Paclobutrazol, which was one of the inhibitors used, is xylem-mobile and it efficiently reduced the level of seed gibberellins without being taken up into the seed. In intact fruits the pod may therefore be a source of precursors for gibberellin biosynthesis in the seed. Overall, the results indicate that gibberellin A~, present in parthenocarpic and pollinated fruits early in development, regulates pod growth. In contrast the high levels of gibberellins A2o and A29 , which accumulate during seed enlargement, appear to be unnecessary for normal seed development or for subsequent germination.