Bioactivity of Scytonema hofmanni (Cyanobacteria) in Lilium alexandrae in vitro propagation

Cyanobacteria produces bioactive compounds including plant growth regulators. Naphthalene acetic acid (NAA), a toxic substance, is a synthetic plant regulator used in micropropagation. The aim of this work was to evaluate morphogenetic and antioxidant effects produced by intra and extracellular substances from Scytonema hofmanni (Cyanobacteria) during the multiplication in vitro of Lilium alexandrae and to compare them to those produced by NAA. Intra and extracellular cyanobacterial products increased a) bulblets production reaching 83 percent and 78 percent of NAA effect, respectively; b) the bulblet diameter compared to NAA; and c) the bulblet survival due to the promotion of antioxidant activity measured as catalase, ascorbate peroxidase, and glutathione reductase activity. The cyanobacterial substances stimulated regeneration and delayed bulblet senescence. They could replace NAA, dangerous for the operator, not only during the regeneration phase but also during the storage of the viable bulblets cultivated in vitro.

Establishment of an in vitro micropropagation protocol for Mecardonia tenella

Mecardonia tenella is an attractive herbaceous native plant, characterized by their intense green foliage and their abundant yellow flowers. It is a very interesting plant for pot and/or garden. A trait to improve in this species is the size of the flowers. The goal of the present paper is to study the in vitro behaviour of M. tenella and to establish a routine protocol for its micropropagation. For the in vitro establishment of M. tenella, nodal segments were disinfected by standard methods using ethanol/sodium hypochloride and cultured on hormone-free MS medium, supplemented with a mixture of antibiotics and an antifungal. In order to study the hormonal requirements of the species, nodal segments were cultured on basal MS supplemented with antibiotic/antifungal mixture and the following concentrations of BAP and NAA (mg/L): 0.0; 0.25; 0.5 and 1.0. These plant regulators were tested in all possible combinations. In vitro plants growing in hormone-free medium were used as explant source. The best results were obtained in the treatments containing 0.25 and 0.5 mg/l BAP with a multiplication rate of 32 shoots per explant. The regenerated shoots rooted spontaneously. When transferred to the greenhouse, the ex vitro plants grew and flowered normally.