Biospeckle Laser Analysis in Plant Tissue Culture: Assessment of Root Regions in In Vitro Grown Adenium obesum Plants

Plant tissue culture enables the controlled evaluation of plant responses under in vitro conditions, whereas biospeckle laser analysis (BSL) provides a non-invasive approach for assessing dynamic responses in living tissues. However, its application in plant tissue culture requires methodological standardization, particularly in the selection of the illuminated region. This study aimed to standardize BSL acquisition in in vitro grown A. obesum seedlings by comparing the basal, middle, and tip root regions under two contrasting culture medium conditions. Biospeckle responses were quantified using the Absolute Value of the Differences (AVD) index and graphical AVD (GAVD). A significant culture medium × root region interaction was detected for AVD. In MS medium, the basal region showed the highest AVD values, followed by the middle and tip regions, whereas no significant differences among root regions were observed in the medium without mineral salts. The mean root AVD was positively correlated with dry mass, leaf number, fresh mass, leaf length, leaf width, and root length, indicating an association with seedling performance. These findings support the basal region as a suitable candidate for standardized BSL acquisition in A. obesum under the evaluated conditions and demonstrate that root-region selection should be considered during the methodological optimization.