O. Monteuuis et Mc. Bon, Influence of auxins and darkness on in vitro rooting of micropropagated shoots from mature and juvenile Acacia mangium, PL CELL TIS, 63(3), 2000, pp. 173-177
The influence of total darkness versus a 16/8 photoperiod and of auxins add
ed to the culture medium on the in vitro root formation capacity of Acacia
mangium microshoots of juvenile and mature origin was examined. Rooting of
the mature clone was significantly increased by exposing the microshoots to
auxins (4 and 6 muM IAA or IBA) in darkness, while the promoting effect of
darkness combined with 4 muM IAA was more time-restricted for the juvenile
-origin microshoots. Overall, the latter rooted in greater proportions than
those from the mature source. Maintaining the microshoots of both origins
on auxin supplemented medium in darkness resulted in a greater number of ad
ventitious roots formed than under the standard 16/8 lighting conditions. O
n the other hand, light stimulated root elongation. These results are discu
ssed mainly from the viewpoint of auxin metabolism in relation to adventiti
ous root formation.