Effects of vessel permeability to gas exchanges on the in vitro plantlets of myrtus communis l.

摘要

Apical microcuttings of Myrtus communis L. (myrtle) were rooted in vessels containing perlite soaked in half strength MS mineral solution nad 15 g 1~(_1) sucrose. Rooting percentage, number and length of the roots were similar in media supplementedwith 0.5 mg1~-1 indolebutyric acid (IBA) or 0.5 mg 1~-1 #alpha#-naphthaleneacetic acid (NAA). Two types of closure device were also compared during experiments on myrtle in the pre-acclimatization phase: caps with air permeable membranes ("aerated vesels") and traditional caps without apertures ("closed vessels"). The number fo gas exchanges/hour in closed vessels was E=0.3 while in aerated vessels this was markedly enhanced (E=1.4). Growth and rhizogenesis of myrtle microcuttings were more vigorous incontainers permeable to air than in closed ones. The CO_2 assimilation rate (NPR) of myrtle plantlets measured in situ in aerated vessels showed values 2-2.5 times higher than the NPR of plantlets cultured in closed containers. During the first two weeksfo growing exvitro, rooted myrtle plantlets derived from the two in vitro micro-environments retained significant differences in growth and NPR and the myrtle ex vitro plants derived from the aerated system showed a higher survival percentage.