CORRELATIVE INFLUENCE OF SEEDLING AGE, COTYLEDONS AND TERMINAL BUDS ON ADVENTITIOUS ROOT FORMATION IN STEM CUTTINGS OF MUNG BEAN

Abstract

Rooting response in stem cuttings of mung bean increased considerably with inresing
seedling age, due to endogenous IAA or supplied IBA. However, after the day 7- or 8-old of
seedling age. The cotyledons sheivel and drop-off spontaneously at day-8 of seedling age. So
that cotyledons excision after cuttings were made during the period between seedling
emergence (the day 4) and cotyledons dropping off (which starts at day 8 and its completion
at day 10) causes decrease in rooting at any time during cutting treatment ,in particular, at
zero time . In addition, results of this study revealed that terminal buds do not influence
significantly adventitious root formation whether IBA supplied or not. Whereas in leafless
cuttings, excision of terminal buds at any time enhance rooting of cuttings specially at zero
time, compared with its presence. The correlative role of cotyledons and terminal buds as a
source of endogenous IAA and rooting co-factors and their influence on seedling
development and subsequently on rooting response of cuttings derived from them. In addition
to role of leaves on uptake and subsequent transport of supplied IBA have been discussed.
Key Words: Adventitious roots, Auxin, Stem cuttings, Seedling age, Cotyledons, Terminal
buds, Correlative phenomena.