Lemon balm (Melissa officinalisL.) is a medicinal plant with a long history in traditional medicine. Classical propagation of this species is inefficient for establishing a good quality clonal plants. The aim of this work was to elaborate an in vitro propagation protocol for M. officinalis using apexes and uninodal fragments as explants. The highest multiplication rate (4.7 shoots/explant) was obtained on a MS medium supplemented with 3 mg/L BAP. A half strength MS medium supplemented with 1 mg/L NAA was the most effective for in vitro rooting of lemon balmmicroshoots. Micropropagated plants transferred ex vitro showed normal morphology and 95% survival rate during acclimatization. The results obtained throughout the in vitro regeneration phases confirm that in vitro tissue culture is an efficient method for multiplication of M. officinalis.

Climatic conditions from areas where vine is cultivated or intended to be cultivated are essential and important to be acknowledged especially in the context of climatic changes that have taken place during the last 50 years. In this regard, prevention solutions are recommended to be implemented as well as solutions that decrease the damages caused by climatic changes or other stress factors. Among these solutions we mention the reorientation of vine areas, planting shelter-belts in areas and regions exposed to high intensity winds, reconsidering the structure of viticultural varieties or selecting the cultivated vine varieties.

Salvia officinalis L. (sage) and Melissa officinalis L. (lemon balm) are two valuable medicinal plants from Lamiaceae family. Considering the therapeutic potential of sage and lemon balm extracts, there is currently great interest to increase the production of biological material and the synthesis of bioactive compounds by different methods. Both micropropagation and gamma irradiation represent efficient methods of stimulating the synthesis of bioactive compounds in plants. In order to produce biological material, it is important to establish the doses of gamma radiation that do not have a phytotoxic effect on plants. The aim of the present study was to evaluate the effect of different doses of gamma irradiation (100, 300, and 500 Gy) on sage and lemon balm by quantifying of some biochemical compounds (assimilatory pigments, soluble carbohydrates, and total polyphenols) in in vitro plants. The results obtained revealed that high doses of gamma radiation have phytotoxic effect on in vitro raised plants. However, micropropagation is an efficient method to produce high quality biological material, source for obtaining extracts with therapeutic potential.