Changes in Poly(a) Rna Metabolism in Relation to Storage and Dormancy‐breaking of Hazel Seed

Abstract

S U M M A R YT h e amounts of abscisic acid (ABA) in different parts of the seed have been investigated during dry storage, which induces dormancy. ABA occurs within the embryonic axis as well as in testa and cotyledon. T h e amount of ABA in the whole seed markedly declines during dry storage, although there is a transient increase within the embryonic axis. T h e incorporation of 3zP0,3into poly(A)-rich RNA within the axis declines during dry storage. Imbibition results in increased poly(A) RNA synthesis but the presence of the testa is inhibitory to this synthesis. GA, on the other hand promotes synthesis. Poly(A) RNA synthesis within isolated embryonic axes is inhibited by ABA. These results are discussed with respect to the induction, maintenance and breaking of dormancy.

Gene expression analysis by cDNA-AFLP highlights a set of new signaling networks and translational control during seed dormancy breaking in Nicotiana plumbaginifolia

“…However, it was not known how desiccation and rehydration bring about these changes in patterns of protein synthesis. Jarvis and Shannon (1981) had shown the inhibitory effect of ABA on transcription and observed a strong translational control but did not propose that ABA is responsible for this phenomenon. Our global analysis of gene regulation linked to dormancy maintenance and breaking, provides strong support for the idea that these changes in protein synthesis activity are at least in part programmed during after-ripening and early imbibition.…”

Effects of moist stratification, GA3 and seed age on seed germination of Rheum khorasanicum B. Baradaran & A. Jafari

“…Moreover, increasing stratification period, improved germination characteristics, so that the maximum percentage (81%) and rate (0.085) of germination obtained in seeds soaked in 500 ppm GA 3 for 48 h and then stratified in 2 • C for 30 days. Treatment of hazelnut seeds with GA amplified the effect of cold storage on the expression of genes associated with germination (Jarvis and Shannon, 1981). The effect of GA 3 as a germination promoter is hypothesized to increase with chilling treatment.…”