Polarity of Transport of Benzyladenine, Adenine and Indole-3-acetic Acid in Petiole Segments of Phaseolus vulgaris

Abstract

The transport of Cl4-benzyladenine (6-benzylaminopurine), Cl4-indoleacetic acid and Cl4-adenine was studied in excised segments from the young petioles of primary leaves of P. vulgaris. Transport of benzyladenine was basipetally polar, and in the presence of indole-acetic acid the rate of basipetal benzyladenine increased, especially in segments cut from petioles in which endogenous auxin was presumed to have been depleted by first placing excised debladed plants in the dark for 16-18 hours. The per cent of benzyladenine transported basipetally was similar to that of indoleacetic acid. Benzyladenine increased the rate of indoleacetic acid basipetal transport in petioles in which endogenous auxin was presumed to have been depleted. After a lag period of about 21/2 hours, the stimulation in rate lasted about an hour. The increase was the same whether the kinin was applied to the segment in donor or receiver agar blocks. When radioactive adenine was supplied to bean segments, adenine itself was not recovered at the receiver end, but an unidentified metabolite of adenine was transported in a predominantly basipetal direction.