The effect of light quality on the morphogenesis of in vitro cultures of Azorina vidalii (Wats.) Feer

In the present study, the possibility to improve the multiplication rate and quality of in vitro cultured plants of Azorina vidalii (Wats.) Feer was investigated. For these purposes the influence of high and low ratios of blue/red light (2.3 and 0.9, respectively) and red/far red light (1.1 and 0.6, respectively) on the development of shoot cultures of Azorina vidalii (Wats.) Feer was evaluated. Maximum plant length (87.9 +/- 5.3 mm) (p less than or equal to 0.05) and internode length (6.6 +/- 0.5 mm) (p less than or equal to 0.05) were obtained for the plants cultured under the low ratio of red/far red light. In contrast, when blue light was supplemented, plant height was reduced, due to shorter internodes. Highest number of axillary shoots per plant (2.4 +/- 0.5) was obtained in the plants growing under a high level of red/far red light, while the lowest number (0.7 +/- 0.2) was obtained in the plants cultured under the low level of red/far red light. Leaf area was increased in plants cultured under a low level of red/far red (1,522.5 +/- 129.5 mm(2)) while blue/red light treatments inhibited leaf expansion. For chlorophyll a and total carotenoid contents, statistical differences (p less than or equal to 0.05) were observed between the plants exposed to the red/far red light treatments and the plants from the control.