Levels of Growth Regulating Substances during Vernalization of Winter Wheat

Abstract

Seeds of winter wheat (Triticum vulgare L.) cultivars Fema and Ferto, were vernalized at 3°C in the dark. Samples were taken 9, 18, 27, 36 and 45 days after the start of vernalization, and extracts were analysed for auxins, gibberellins and growth inhibiting substances. As vernalization progressed the levels of auxins and gibberellins increased whereas the levels of growth inhibitors decreased. The pattern of growth regulator changes was almost similar in both the cultivars. Vernalization seemingly controls the balance between growth promoting and growth inhibiting substances in winter wheat.

Thermoinduction of genes encoding the enzymes of gibberellin biosynthesis and a putative negative regulator of gibberellin signal transduction in Eustoma grandiflorum

“…This result suggests that the multifunctional enzyme GA20 oxidase in the early 13-hydroxylation pathway functions during the vernalization treatment, since this metabolism is a major GA biosynthetic pathway in E. grandiflorum (Hisamatsu et al 1998). Increases in certain GA-like substances in vernalized tissues have also been indicated in winter wheat (Reda et al 1978) and radish (Michniewicz et al 1981). In winter canola, bioactive GA accumulated during vernalization (Zanewich and Rood 1995).…”

Vernalization and Gibberellin Physiology of Winter Canola (Endogenous Gibberellin (GA) Content and Metabolism of [3H]GA1 and [3H]GA20

“…Although a few studies have investigated the endogenous GA content of vernalized compared to nonvernalized plants using either bioassays or GC-MS, results have been variable (Suge, 1970;Michniewicz et al, 1981;Joseph et al, 1983;Lin and Stafford, 1987). Bioassay results with Brassica napus (Margara, 1963), Brassica rapa (Suge and Takahashi, 19821, chicory (Joseph et al, 19831, radish (Suge, 1970;Michniewicz et al, 1981), and winter wheat (Chailakhyan and Lozhnikova, 1962;Reda et al, 1978) have indicated the presence of additional GA-like substances or increases of certain GA-like substances in vernalized tissues. In contrast, in another member of the Brassicaceae, Thlaspi arvense, increases in endogenous GA-like substances did not appear to be directly induced by low temperature, but rather thermoinduction may have resulted in altered GA sensitivity or GA metabolism (Metzger, 1985).…”