Free and conjugated gibberellins in dormancy and germination of apple seeds

Abstract

Halińska, A. and Lewak, St. 1987. Free and conjugated gibberellins in dormancy and germination of apple seeds.The presence of gibberellin A4 (GA4) was confirmed in partly stratified seeds of apple (Malus domestica Borb., cv. Antonówka) by mass spectrometry of the methyl ester. Levels of free and conjugated gibberellins A4+7 and A9 changed during drying of mature seeds, during cold and warm stratification, as well as during germination of dormant and non‐dormant embryos. The temporary rise in GA4+7 during cold stratification and during the culture of dormant embryos as well as the lack of it under conditions of warm stratification, allowed us to postulate a role for GA4+7 in the removal of dormancy. In addition, GA9 was absent in dormant embryos and increased during cold stratification and during the culture of non‐dormant embryos. This suggests the involvement of GA9, in induction of normal development of the seedling. The equivalence between changes in free and conjugated GAs suggests that formation and hydrolysis of conjugates are involved in the control of the physiologically active levels of free GA4+7 and GA9.

Effects of cyanide and cold treatment on sugar catabolism in apple seeds during dormancy removal

“…lA). Since the warm stratification conditions did not eliminate the embryonal dormancy in apple seeds (Wyziriska and Lewak 1978, Haliriska andLewak 1987), the fluctuations observed in the course of cold stratification could indicate a role in dormancy removal for the alterations of the ratio between the paths for glucose catabolism.…”

“…Mature apple seeds achieve full germination capacity only after several months of after-ripening under conditions of cold stratification. Treatment of imbibed seeds at 25°C (warm stratification) does not remove the embryonal dormancy of apple seeds (Wyziriska and Lewak 1978, Halitiska andLewak 1987).…”

Changes in endogenous gibberellin activity during winter dormancy in tea (Camellia sinensis (L.) O. Kuntze)

“…In the present study a reasonable equivalence between the increase in activity of free GAs and the decrease in the activity of GA conjugates and vice versa indicates that this mechanism may be active. The equivalent changes in free and conjugated GAs in Corylus (Arias et al 1976) and apple (Halinska and Lewak 1987) seeds is suggestive of the formation and hydrolysis of conjugates in the control of physiologically active levels of free GAs.…”

The long-term ambient storage-induced alterations in seed viability, germination and seedling vigour of Saussurea costus, a critically endangered medicinal herb of North West Himalaya

“…Gibberellins stimulate germination by inducing hydrolytic enzymes that weaken the barrier tissues such as the endosperm or seed coat, inducing mobilization of storage reserve and therefore, the embryo expansion (Finkelstein et al, 2008;Groot and Karssen, 1987;Koornneef and Van der Veen, 1980). Low temperature treatment is known to activate GA synthesis and/or increase the sensitivity of embryo towards GA which ultimately enhances the embryo growth potential (Halinska and Lewak, 1987). The promotory influence of GA 3 and chilling was not restricted to the freshly harvested seeds only but was also evident during certain, but not all, storage regimes.…”