Influence of exogenous spermidine on potassium balance in maize seedlings
1993
De Agazio, M. | Rea, E. | De Cesare, F. | Grego, S.
Two-day-old maize seedlings were incubated in the presence or absence of 1 mM spermidine in the external medium. After 2 h, an increase of potassium (K+) efflux from roots was observed in treated seedlings up to a maximum after a 4 h treatment, decreasing to control values in the following hours. Simultaneously, an inhibition of K+ uptake occurred in roots from treated seedlings up to minimum values after 7-9 h treatment. Successively, roots from treated seedlings progressively recovered their K+ uptake capacity up to values about 50% higher than control seedlings. No variations in K+ content were observed after 24 h between control and spermidine-treated seedlings taken as a whole, while the K+ content of roots and shoots showed different values when individually analysed. Our results suggest that for spermidine-treated plants, the K+ content is maintained constant after 24 h by an equilibrium of the influx/efflux systems while a different K+ content in shoots and roots is related to a different growth rate induced by the presence of spermidine in the external medium.
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