Influence of photoperiod on seed development in the genetic line of peas G2 and its relation to changes in endogenous gibberellins measured by combined gas chromatography ? Mass spectrometry

Abstract

When apical senescence in the genetic line of peas G2 was prevented by short days fruit development was also found to be retarded. The levels of GA20 and GA29 in cotyledons and pods grown under long or short days were measured by gas chromatography - mass spectrometry multiple ion monitoring using extracts derivatised with deuterated trimethylsilyl groups as internal standards. The levels of GA20 but not GA29, were increased by short days. Conventional gas chromatography - mass spectrometry showed that relative to GA29 the levels of GA19, the other GA identified in G2 cotyledons, were also increased in short days. The levels of GA20 in the pods were highest during the main phase of pod growth early in fruit development.

Metabolism of Gibberellin A12 and A12-Aldehyde in Developing Seeds of Pisum sativum L.

“…The GAs may be involved in seed growth, and the levels of GA9 and GA,(2 do rise and fall during seed growth (7). However, the presence of thousands of nanograms of GA in the cotyledons of G2 peas casts doubt on such a role because the amount seems excessive for physiological action, being two or three orders of magnitude greater than that present in vegetative tissue (5,15), although that amount of GA20 may be needed for the production of GA,. In addition, pods cultured in vitro in the presence of the GA biosynthesis inhibitors produced nearly normal seeds despite large reductions in the amount of biologically active GAs (10).…”

“…been the subject of numerous studies. Earlier work has shown that there are 11 GAs present in developing pea seeds, namely, GA., GA,,, GA2-aldehyde, GAI7, GA,9, GA,(, GA,9, GA29-catabolite, GA44, GA5,, and GA53 (5,8,9,15,18,24,25,26,29,30). The levels of those GAs, especially of GA2N, GA29, and GA2,-catabolite, were found to be substantially higher in immature seeds than in other parts of the plant (5).…”

Seed Effects on Gibberellin Metabolism in Pea Pericarp

“…In pea (Pisum sativum L.), normal pod (pericarp) growth requires the presence of seeds (4); developing seeds contain high levels of GAs3 (11,12); and the requirement for seeds can be replaced by application of the plant hormone, GA (4, 17). Based on these observations, it has been assumed that the GAs biosynthesized by seeds are transported to the pericarp and regulate pericarp growth (6).…”

“…Deseeded pericarp contained no detectable GA20, GA1, or GA8, whereas pericarp with seeds contained endogenous and radiolabeled GA20 and endogenous GA1. These data strongly suggest that seeds are required for normal GA biosynthesis in the pericarp, specifically the conversion of GA1, to GA20.In pea (Pisum sativum L.), normal pod (pericarp) growth requires the presence of seeds (4); developing seeds contain high levels of GAs3 (11,12); and the requirement for seeds can be replaced by application of the plant hormone, GA (4, 17). Based on these observations, it has been assumed that the GAs biosynthesized by seeds are transported to the pericarp and regulate pericarp growth (6).…”

Maternal, Single-Gene Regulation of Assimilate Partitioning in Pea

“…Finally, we wished to determine whether the genotype of the embryo, and therefore events in the embryo, controlled seed filling in Sn lines, a finding that would discredit the hypothesis that the Sn gene is maternally expressed. Results of severa1 studies support the conclusion that the Sn gene inhibits reproductive growth (Gianfagna and Davies, 1981;Ingram and Browning, 1979;Davies, 1986, 1988). However, a 1984 study (Duchene, 1984) is the most similar to ours, in that nearly isogenic lines differing at the Sn locus were also used, although the lines used in that study were recessive for Hr (which magnifies the Sn effect and is required for the G2 phenotype; Murfet, 1977).…”