Uptake of benzyladenine by excised watermelon cotyledons.
The uptake of 8-[(14)C]N(6)-benzyladenine (BA) was studied in excised watermelon (Citrullus vulgaris Schrad.) cotyledons 24 hours after the start of imbibition. The passive nature of this uptake is suggested by the following evidence: (a) no sign of saturation on increasing external concentration of BA; (b) no decrease in uptake under conditions that inhibit ATP synthesis; (c) no change in amount of radioactivity absorbed when cotyledons are frozen and thawed before the uptake test. About two-thirds of the radioactivity taken up is released after 12 hours of washing. If the washing is performed at 2 C very little radioactivity is released.There seems to be a correlation between the level of radioactivity (i.e. of BA + derivatives) present in the cotyledons and the magnitude of hormonal responses that are observed four days after uptake. This relationship holds regardless of whether a given level of radioactivity has been reached after a short period of uptake or after a long period of uptake followed by washing.
Lampugnani
M G
MG
Centro di Studio del CNR per la Biologia Cellulare e Molecolare delle Piante, Istituto di Scienze Botaniche, Università di Milano, via G. Colombo, 60, 20133 Milano, Italy.
Fantelli
R
R
Longo
G P
GP
Longo
C P
CP
Rossi
G
G