In vitro culture and aclimation process of Stevia Rebaudiana
Conference Paper
Overview
Research
View All
Overview
abstract
Stevia rebaudiana (Bert.) Bertoni (Asteraceae) leaves are a natural source of steviol glycosides, which can be used
for sweetening and flavouring foods and beverages.
The recent interest of farmers on this crop has increased the demand for propagation material. The farmers can use
seedlings, cuttings or, alternatively, wealthy plants obtained from in vitro propagation (Madan et al., 2010). This work
reports the results of a simple, fast and non-expensive method developed for micro-propagation, rooting and
acclimation of Stevia .
Objectives: development of a method to micro-propagate, rooting and acclimate Stevia.
Methodology: plant material was collected from a commercial clone growing in field. Plant material was sterilized by
stirring for 7 minutes in a solution of chlorine 5% plus 10 drops of tween 80 per 100 ml of chlorine solution .
Thereafter, the explants were washed in sterilized water and moved to a solution of ethanol 70%, kept there for 5
minutes, washed again and inoculated in two different culture media (medium A- MS without hormones and 20 g/L of
sucrose; and medium 8- MS with 0.5 mg/L of kinetin and 20 g/L of sucrose). The multiplication rate was determined
for each subculture of 2 months in the two media tested. As complementary data, the fresh weights of 10% of the
micro-propagated plants per subculture were determined. The rate of spontaneous rooting was also determined, and
trials of plant rooting performed through auxin shocks using 2mg/ ml of IBA (lndole-3-butyric acid)(Abdullateef and
Osman,2012), a solution to dip the basal part of 100 Stevia plants for 30 seconds. Thereafter, the plants were
transferred to the MS media without hormones but containing activated coal. The time that the plants take to get a
minimum of roots allowing them to acclimate to the soil substrate was recorded. The acclimatization in soil substrate
was performed in a greenhouse under a misting irrigation system working for 1 0 seconds each 20 minutes. The
acclimatization rate was determined during two weeks .
Results: In culture media A and 8 the monthly multiplication rates were 383.2 and 306.9%, respectively. The mean
plant fresh weights per subculture were 1.1 and 0.9 g, respectively for A and 8 subculture media. In medium A, the
rate of spontaneous rooting, after 4 months in culture, was 1 0.5%, and in 8 medium was less than 4%. Rooting
induced process was evaluated each week after hormone shock. In the first week, 30% of plants developed roots,
having increased this number to 70% in the second week. No significant differences were found in rooting of plants
coming from the different initial media growth. The acclimatization rate was 100% after 2 weeks in the greenhouse.
Conclusion: Using the medium A (the best suited for multiplication and spontaneous rooting) it was possible to obtain
more than 50 times the initial number of plants in excellent developing conditions to be transferred to the field.
