Role of endogenous gibberellins in germination of melon (Cucumis melo) seeds

Abstract

J. 1995. Role of endogenous gibberellins in germination of melon (Cucumis melo) seeds. -Physiol. Plant. 95: 113-119.The effect of the plant growth retardants ancymidoi, mefluidide and uniconazole on germination of two melon accessions differing in their ability to germinate at 14°C was examined. The accessions were the cold sensitive Ncy Yizre e! and the cold tolerant Persia 202. The three growth retardants were able to delay the germination of intact Noy Yizre'el seeds, but did not affect that of intact Persia 202 seeds. On the other hand germination of decoated seeds of both accessions was unaffected by these inhibitors at normal oxygen concentration, but was inhibited at 5% oxygen. When gibberelhn-like activity was measured by a dwarf rice biological assay following HPLC fractionation, it was found that seeds of Persia 202 contained much more gibberellin-like activity than Noy Yizre'el seeds. Among the extracted compounds several endogenous gibberellins were identified by combined gas chromatography-mass spectrometry (GC-MS). They included GAj, GAJB, GA, and GA, in Noy Yizre'el and GA,4, GAj), GA| and GAs in Persia 202. It is suggested that the better germination of intact Persia 202 seeds, compared to Noy Yizre'el seeds at low temperature and low oxygen concentration, is due to a higher endogenous level of GA and a better seed coat permeability to oxygen.

Controlling Height and Seedling Emergence of French Marigold and Celosia Plugs with Plant Growth Regulators

“…For example, chlormequat inhibited germination only in decoated celery seeds, whereas paclobutrazol, uniconazole, or ancymidol inhibited germination of both intact and decoated seeds (15). Soaking melon seeds in ancymidol or uniconazole solutions delayed germination, but the delay was less noticeable in the presence of seed coats (3). A semipermeable membrane underneath the seed coats could be an additional structure restricting penetration of certain PGR into seeds (2,18).…”

Germination ofPterocarpus angolensisDC. and evaluation of the possible antimicrobial action of the phloem sap

“…BAS 106 and tetcyclasis) that inhibit GA synthesis, which consequently inhibit seed germination (Kepczynski, 1986;Derkx & Karssen, 1993). Gibberellins, when exogenously applied, promote the seed germination of several' species (Karssen et af., 1989;Edelstein et al, 1995;Leubner-Metzger et at., 1996& Yongqing et aI., 1996. It is a well-known fact that exogenous GA replaces light and low temperatures in the breaking of dormancy (Hilhorst & Karssen, 1988;Derkx & Karssen, 1993& Leubner-Metzger et aI., 1996.…”