EVALUATION OF PHICOCYANIN PRODUCTION BY Anabaena variabilis USING DIFFERENT ORGANIC CARBON SOURCES

Phycocyanin (PC) is one of the phycobiliproteins, pigments found in cyanobacteria, which can be used as natural dyes, antioxidants and fluorescent markers. This study aimed to investigate the effect of supplementation of the basal culture medium (BG110) of the cyanobacterium Anabaena variabilis with different sources of organic carbon in concentration of 1 g⸱L-1, evaluating the production of biomass and PC. The best condition obtained was the medium supplemented with glucose that produced 75.36 mg⸱g-1 PC, about 5 times greater than the control with 14.57 mg⸱g-1 PC. All supplemented media also showed higher biomass production compared to the basal medium, again to stand out for the glucose medium, presenting 0.29 g⸱L-1 of dry biomass.

Effect of two cytokinins and a growth inhibitor on the in vitro tuberization of two genotypes of Solanum tuberosum L. cvs. Atlantic and Alpha

This investigation was carried out to evaluate the effect of two cytokinins: 6-benzilaminopurine (BAP) (6.5 mg l-1) and kinetin (K) (2.5 mg l-1), as well as the growth inhibitor abscisic acid (ABA) (1.0 mg l-1) on the in vitro tuberization capacity of two potato varieties: Atlantic and Alpha. The basal culture medium MS (1962) was used as a control. The responses were different between varieties. In cv. Atlantic, the analysis of the number (NM), weight (WM) and diameter (DM) of microtubers indicated that the addition of growth regulators did not affect induction and development of microtubers. However, when BAP was used, a non-significant increment of 41 % was observed in the number of the microtubers compared to the control treatment, from 2.6 to 4.4. The addition of cytokinins and ABA to the medium did not have a significant impact on the development of microtubers. In cv. Alpha the cytokinins used without ABA increased the number of microtubers, which were larger and heavier than those of the control treatment. In this variety, ABA significantly reduced the values of the NM, WM and DM variables. The exogenous action of cytokinins in the culture medium is likely to have caused an endogenous hormonal imbalance in the Atlantic and Alpha genotypes which interfered with their innate microtuberization ability, a result that was even more evident for cv. Alpha, which showed the need to continue optimizing protocols of genotype-specific systems in potato tissue culture to increase yield and seed quality.

In Vitro Propagation of a Vietnam Endemic Lady’s Slipper Orchid (Paphiopedilum vietnamense O.Gruss & Perner)

P. vietnamenseO. Gruss & Perner is one of the endemic lady’s slipper orchids in Vietnam that has been known as an endangered species threatened with extinction due to over-collection. To protectP. vietnamensespecies,In Vitropropagation method needs to be established for producing plantlets that can be introduced back in wild, as well as commercialized. In this study, we examined the effect of basal culture medium, plant growth regulators, and AC on the micropropagation ability ofP. vietnamense, which were collected from wild population in Thai Nguyen province, Northeastern Vietnam. We determined that the 0.2% HgCl2can be used in within 5 to 10 min for sterilizing axillary buds ofP. vietnamense, resulting in 65.55% of disinfected samples. Moreover, the 1/2 MS medium supplemented with 2.0 mg 1-1BA and 1.0 mg 1-1NAA, which gave about 2.85 shoots/sample, was the most suitable for shoot regeneration and multiplication. In addition, the result also indicated that 0.5 mg 1-1NAA and 1.0 g 1-1AC gave the best results (88.89%) for root induction and plantlets

In vitro organogenesis in some citrus species

In vitro organogenesis of Citrus was studied for the genotypes Citrus sinensis cv. 'Natal', C. limonia, C. volkameriana, and C. aurantium, with the use of epicotyl segments-derived explants, cultured in MT salts and vitamins medium supplemented with different concentrations of 6-benzylaminopurine (BAP - 0.0; 0.5; 1.0; 1.5 or 2.0 mg L-1). For the recalcitrant genotypes C. limonia and C. aurantium the in vitro organogenesis was also studied with internodal segments-derived explants, cultured in MT salts and vitamins medium supplemented with 0; 0.5; 1.0; 2.0, or 4.0 mg L-1 of BAP. The efficiency of culture medium supplementation with the combination of BAP (0.0; 1.0, or 2.0 mg L-1) and NAA (1-naphthaleneacetic acid - 0.0; 0.3, or 0.5 mg L-1) in the development of adventitious shoots was evaluated for C. aurantium. Culture medium supplementation with BAP is not essential for the adventitious shoots development in the four genotypes studied when epicotyl segments-derived explants are used. In general, culture media supplementation with BAP decreased the percentage of responsive explants excepted for C. sinensis cv. 'Natal' and C. limonia when the concentrations of 1.5 and 2.0 mg/L were used. The presence of cytokinin, in concentrations up to 2 mg/L, stimulated the in vitro organogenesis when internodal segments-derived explants were used for C. limonia and C. aurantium. For C. aurantium no adventitious shoots developed in explants (internodal segments) cultured in basal culture medium, without BAP supplementation. Although no statistic differences could be detected, culture media supplementation with the combination of BAP and NAA favored the development of adventitious shoots in C. aurantium. The best concentration of NAA varied according to BAP concentration. The results presented herein, show that Citrus in vitro organogenesis depends on the interaction of culture medium composition, explant differentiation level, and genotype.