Responses of lemon balm (Melissa officinalis L.)genotypes to salt stress in vitro and in vivo conditions

This study was conducted in Tissue Culture Laboratory of Department of Field Crops and Biotechnology Laboratory of Agricultural Faculty during 2011-2012. In the study, a genotype grown in Kazdağı (Ida Mountain) flora, a genotype grown in the region of Çanakkale as a local line and an Italian genotype were used. The aim of the study is to determine the responses of lemon balm genotypes to salinity in both in vitro and in vivo conditions, and to investigate the relationships between the characters measured in vitro and in vivo conditions. At first, using the axillary shoots obtained from the sterile in vitro plantlets, the responses of lemon balm genotypes to MS medium supplemented with different concentrations of NaCl were determined. In this in vitro experiment, all measurements taken decreased with increasing salt concentrations. For example, plant height with the highest salt treatment (%1,00) was 13% compared to the control). There were also significant differences between the genotypes in terms of their responses to salinity. According to correlation analysis, all measured characters were positively and highly correlated each other. In the second stage, the plantlets were transferred to in vivo condition from in vitro conditions. And then salt concentrations were used to determine the response to plantlets in vivo condition. Plant fresh weight reduced to 66% at %0,4 salt concentration compared to the control. When ion balance in plant is considered, some of them decreased whereas some of them increased. With the salt effect, amount of total protein decreased while total mineral elements measured in plants increased. In order to compare in vitro and in vivo condition, the results of correlation analyses indicated that the highest and significant correlation coefficient (-0,72) was obtained between in vitro plant height and in vivo Na content. As a result, these significant correlations showed that in vitro salt screenings prior to in vivo screenings may give some information about the responses of the genotypes.