Promotion of adventitious root formation by 4-chlororesorcinol: A polyphenol oxidase inhibitor

Abstract

The extent of rooting in cuttings of Phaseolus vulgaris L ., and Vigna radiata Wilcz. was affected by 4-chlororesorcinol, a polyphenol oxidase inhibitor . More root primordia and more roots were formed after 4-chlororesorcinol treatment both with and without 10 -'M Indole butyric acid . Promotion of rooting was observed also in cuttings of Elaeagnus pungens, Gypsophilia elegans and Kalanchoe blossfeldiana . The enhancement in bean and mung bean was accompanied by a concomitant wider spatial distribution of the primordia and the resulting adventitious roots . The formation of primordia in the treated cuttings was delayed by 12-24 hours, compared to untreated cuttings . The treatment was effective only when given during the first hours after the preparation of the cutting of bean and mung bean, suggesting involvement in the initiation stage . Hypocotyl extracts of mung bean cuttings, pretreated with 4-chlororesorcinol, exhibited reduced polyphenol oxidase activity . The inhibition was not reversed by washing of the treated extract in 50% acetone or by an overnight dialysis, suggesting tight or maybe even irreversible binding of the inhibitor to the enzyme .

Reviewing current knowledge on olive (Olea europaea L.) adventitious root formation

“…Later, a protein complex corresponding to polyphenol oxidase (PPO), POX, and IAAox, was reported to emerge in the early stages of rooting of Phaseolus aureus (Frenkel and Hess, 1974). Treatment of cuttings with a PPO inhibitor promoted root formation in Phaseolus vulgaris and Vigna radiata, and its effect was more pronounced during the initiation phase (Gad and Ben-Efraim, 1988), suggesting that PPO had a main role in the regulation of adventitious root formation. However, in contrast, Upadhyaya et al (1986) claimed that POX and PPO were not involved in the initiation of roots, but rather in their development.…”