In vitro conservation of enset under slow-growth conditions

Studies on in vitro storage of enset under slow-growth conditions were carried out to develop an efficient protocol for conservation of the genetic diversity of the crop. The response to different growth retardation treatments was examined using three enset clones collected from southwestern Ethiopia. In vitro cultures could be effectively maintained for 6 months at 15 °C and 18 °C on MS medium supplemented with 10 μM BAP, in the presence of mannitol at concentrations of 0, 1 or 2% as a growth retardant. Shoots were subsequently recovered and multiplied on MS medium supplemented with 10 and 20 μM BAP at 25 °C and rooted shoots were successfully transferred to the greenhouse. Incubation at the lower temperature (15 °C) and the presence of mannitol in the culture medium had a significantly positive effect on maintenance, measured by the number of recovered shoots after storage. This revised version was published online in June 2006 with corrections to the Cover Date.     

In vitro regeneration and micro-propagation of enset from Southwestern Ethiopia

Three clones of enset (Ensete ventricosum Welw. Cheesman) from southwestern Ethiopia (Keffa-Shaka zone) were investigated for their potential for micropropagation and regeneration in tissue culture. Corm and leaf tissue of greenhouse-grown plants as well as in vitro germinated zygotic embryos were used as starting material for micro-propagation and regeneration studies. Embryos were excised from disinfected seeds and cultured in vitro. Multiple shoots from both corm- and embryo-explants were obtained using regeneration medium supplemented with 10 μM or 20 μM BAP. Rooting of shoots was achieved using medium with 5 μM IBA, 1 μM BAP and 1 g l⁻¹ activated charcoal. Plantlets obtained by this process were transferred to soil under greenhouse conditions. Optimal conditions, which were determined for clonal propagation of three different genotypes of enset, allowing both in vitro micropropagation and regeneration, are described. This protocol makes for conservation of enset clones, rapid propagation of selected disease-free germplasm and more efficient breeding procedures. This revised version was published online in June 2006 with corrections to the Cover Date.     

Pollination Ecology of a Pioneer Species: Musa itinerans (Musaceae) in Xishuangbanna,South Yunnan,China

Pollination ecology of Musa itinerans Cheesman (Musaceae), a pioneer species in the tropical rain forest, was explored in Xishuangbanna, South Yunnan, China. This research involved flowering phenology, nectar production, visitation patterns of pollinators and bagging experiments. It was found that (1) flowering of M. itinerans occurred a whole year round with a peak at the early dry season (Nov.) and the daily flowering pattern had two obvious peaks in the early morning and in the late evening, respectively; (2) nectar production occurred at two obvious peaks, during the day and in the night-time (from 8 am to 12 pm, and from 8 pm to 12 am, respectively), which allowed the two different foragers to visit at specific times; and (3) long-tongue fruit bats ( Macroglossus sobrinus ) and sunbirds ( Arachnothera longirostris ) were both effective pollinators of Musa itinerans.