In vitro organogenesis from root culture segments of Bixa orellana L. (Bixaceae)

The organogenic potential of root explants derived from cultured seedlings of Bixa orellana L. (annatto) was investigated in response to different incubation conditions and either 4.44 μM 6-benzyladenine, 4.54 μM Thidiazuron, or 4.56 μM Zeatin. Explants cultured in liquid media with agitation generally showed better development of adventitious buds versus explants cultured on semi-solid media. The most adventitious buds developed from explants cultured in liquid media under a 16-h photoperiod. Use of Zeatin and Thidiazuron promoted the development of more adventitious buds than 6-benzyladenine but morphological abnormalities among regenerating shoots and plants were observed. Fewer adventitious buds developed from explants cultured in liquid media supplemented with 6-benzyladenine, but the buds gave rise to the highest percentage of morphologically normal regenerated plants. Histological analyses showed that adventitious buds originated from cell proliferation within the pericycle, opposite the protoxylem poles of the explant. Seedling root tissue is useful for in vitro propagation of B. orellana

Organic Photonics for communications

Photons as information carriers have the potential to meet the ever-increasing demands on bandwidth and information density in fi elds such as information and communication technology, biomedicine and computing. Organic semiconductors may be well-suited to such applications, thanks to their ability to transmit, modulate and detect light in an architecture that is low cost, fl exible, lightweight and robust. Here we review recent breakthroughs in organic photonics, including ultrafast all-optical modulation in polymer photonic crystals, silicon/organic hybrid systems, gain switching in polymer amplifi ers and lasers, and new devices such as hybrid organic/inorganic electrically pumped lasers