Shoot transition region

An early report of kinetin s action on stimulating cambial activity concerned the transition region between shoot and root on dark-grown pea (Sorokin et al. 1962). Kinetin added alone or with auxins to the sucrose and penicillin solution bathing excised sections of the transition internode produced more normal-looking cambial activity and secondary xylem than did the auxins alone, judging by stained sections cut free-hand. 

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