ISSN:
1573-5087
Keywords:
Euonymus europaeus
;
dormancy
;
gibberellic acid
;
putrescine
;
spermidine
;
diamine oxidase: (DAO)
;
polyamine oxidase: (PAO)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract Previously we showed that dormancy break of spindle tree embryos after gibberellic acid (GA3) treatment was followed by an increase in arginine decarboxylase (ADC) activity (Béranger-Novat N. et al., Plant Sc. 102: 139–145, 1994). These results indicated that arginine decarboxylase pathway mediate hormone-induced growth responses in spindle tree embryos. In the present investigation we show that in GA3-treated embryos diamine oxidase (DAO) increases immediately after putrescine content and the increase in DAO activity paralleles the accumulation of putrescine at the beginning of the culture (before the visible appearance of the radicle). In this system polyamine oxidase (PAO) increases immediately after DAO activity and follows closely the increase in spermidine content. These results demonstrate a direct correlation between the biosynthesis and oxidation of putrescine and spermidine. At every stage of development DAO and putrescine levels are lower than spermidine and PAO levels. Dormant embryos can be distinguished from GA3-treated embryos by a complete lack of putrescine accumulation. In dormant embryos compared to GA3-treated embryos DAO changed more or less in parallel and on the whole seemed to follow the same content and distribution, but the kinetics of the activation of DAOs were different in dormant embryos with a delay of 1.5 day for the first and 1 day for the second peak. During the first days of culture at least up to 4 days the distribution of spermidine and PAO in GA3-treated embryos followed the same pattern observed in dormant embryos, but the levels of spermidine and PAO were greatly reduced in dormant embryos. On the other hand the kinetics of the activation of PAOs were different in dormant embryos with a delay of 1 day. The results suggest that dormant embryos are deficient in their ability to synthesize polyamines efficiently and support the view that spermidine catabolism (via PAO pool) is limiting in untreated embryos during the first days of culture.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1005728313877
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