Evaluation of different methods to overcome in vitro seed dormancy from yellow passion fruit

Seeds from yellow passion fruit (Passiflora edulis Sims) present dormancy imposed by the seed-coat. The present study aimed to evaluate some methods to overcome dormancy of seeds from P. edulis grown under in vitro conditions. The experimental design was completely randomized in factorial scheme (15 scarification methods × 2 substrates: PlantMax® and MS medium), constituting 30 treatments with 10 replicates. The following treatments were established: Control (untreated seeds); seeds soaked in water at room temperature for 12, 24 and 48 h; seeds soaked in hot water at 80°C for 1, 2.5 and 5 min; chemical scarification with sulphuric acid (98%) for 1, 5, and 10 min; immersion of the seeds in absolute ethanol for 5, 10 and 25 min; physical scarification with wood sandpaper (no. 125); and total seed coat removal with a Gavin® mini-vise. After each treatment, the seeds were inoculated in vitro in two sterile substrates (MS medium or PlantMax®). The results show that the best treatment to overcome dormancy of P. edulis seeds was total removal of seed coat with Garvin® mini-vise. This treatment yielded 100% seed germination under in vitro conditions either on PlantMax® or MS medium. Approximately 150 seeds per hour could be decoated according to the operator’s skills. However, in some cases, there was physical damage to the zygotic embryo. Seed treated with sulphuric acid for 1 min also showed promising results (average 0.107). Seeds germinated within seven days after being treated with sulphuric acid and inoculated in vitro in PlantMax® sterile substrate. Moreover, poor germination rates were achieved when seeds were treated with sulphuric acid, followed by inoculation in vitro onto MS medium (0.0711). All seeds germinated on in vitro PlantMax® sterile substrate and presented an epinastic phenotype, possibly due the ethylene biosynthesis in vitro.Keywords: Passiflora, dormancy, seed germinationAfrican Journal of Biotechnology, Vol 13(31) 3657-366

Ethylene synthesis inhibition effects on oxidative stress and in vitro conservation of Lippia filifolia (Verbenaceae)

This study aimed to investigate the effects of ethylene biosynthesis inhibitors on oxidative metabolisms and the in vitro conservation of Lippia filifolia, using the lipid peroxidation index (TBARS), antioxidative enzymes and pigments as biomarkers. We found that EDTA, sodium thiosulfate (STS) and especially Co had protective effects on oxidative stress in tissues cultured in vitro, resulting in a delay of the senescence and the reduction of subcultures frequency, con-tributing to the germplasm conservation of this species

Ethylene synthesis inhibition effects on oxidative stress and in vitro conservation of Lippia filifolia (Verbenaceae)

This study aimed to investigate the effects of ethylene biosynthesis inhibitors on oxidative metabolisms and the in vitro conservation of Lippia filifolia, using the lipid peroxidation index (TBARS), antioxidative enzymes and pigments as biomarkers. We found that EDTA, sodium thiosulfate (STS) and especially Co had protective effects on oxidative stress in tissues cultured in vitro, resulting in a delay of the senescence and the reduction of subcultures frequency, con-tributing to the germplasm conservation of this species

High responsiveness in de novo shoot organogenesis induction of Passiflora cristalina (Passifloraceae), a wild Amazonian passion fruit species

The aim of the present study was to establish a regeneration system via de novo organogenesis from different types of non-meristematic explants of Passiflora cristalina. Leaf, hypocotyl, root segments, cotyledons, and endosperm of P. cristalina seeds were inoculated in Murashige and Skoog (MS)-basal medium, supplemented with different concentrations of 6-Benzyladenine (BA), Thidiazuron (TDZ), or Kinetin (KIN). BA was found to be the most efficient cytokinin in induction of de novo organogenesis from most the explants used in the study. The highest frequencies of adventitious bud formation in the hypocotyl and cotyledon explants were observed in medium supplemented with 1.0 mg L^−1 BA. For leaf and endosperm segments, the best concentration was 2.0 mg L^−1 BA; while for root segments, the highest mean values were observed with 1.0 mg L^−1 KIN. The different morphogenetic responses obtained from each explant source were characterized using light microscopy. P. cristalina revealed a remarkable organogenic potential, with superior production of adventitious shoots compared with the other Passiflora species evaluated elsewhere. These results will be helpful to establish a reproducible and reliable micropropagation protocol, as well as to implement conservationist and biotechnological-based genetic breeding strategies for this wild Passiflora species