Effect of sunlight and artificial light on micropropagation of potato (Solanum tuberosum L.) plantlets

Fluorescent lamps (artificial light) and sunlight were used as lighting source in present study to identify feasibility of using sunlight in plant tissue culture laboratory. In vitroregenerated nodal segments of the cardinal variety of potato (Solanum tuberosum L.) were inoculated in MS medium without any growth regulator for shoot and root development. After 30 days of culture in an average temperature at 21.94±0.21°C, relative humidity 39.35±0.75%, various morphological responses i.e. plantlet height, diameter of plantlet, number of nodes per plantlet, inter node distance, number of leaves per plantlet, fresh and dry weight of plantlets , number of root, length of root, growth rate etc. were recorded. The average light intensity at sunlight and artificial treatment was observed at 4805.5±326.54 lux and 3484±84.44 lux, respectively. All the growth factors performed better result in sunlight treatment than those of artificial one except average number of nodes and leaves. The average height of plantlet at sunlight was 53.33±3.32 mm which was greater than that of artificial light 51.67±2.15 mm. Fresh weight and dry weight are two important morphological factors for plantlet and in case of fresh weight that was always greater 0.49±0.097 in sunlighted plantlet and 0.21±0.026 in artificial one.  In case of dry weight the average weight 0.08±0.016 was greater in sunlighted plantlet than that of 0.03±0.004 in artificial one. Number of roots, root length and growth rate of the plantlets observed higher in sunlighted plantlets compared to artificial light. Moreover, the sunlighted plantlets were healthier, vigorous and strong which helped plants to establish in net house easily. Considering the cost of electricity consumption, from a laboratory area of 20.47 m² BD Taka 63% could be saved in each month by using sunlight. As low cost options of energy saving in tissue culture laboratory using sunlight would be feasible and environmentally friendly technology for commercial point of view in Bangladesh.