Shoot Production of Solanum tuberosum L. 'Yansi' Using a Simple Continuous Immersion Airlift Bioreactor Culture System

A simple in vitro shoot regeneration method was developed for Solanum tuberosum L. 'Yansi' using a simple continuous immersion airlift bioreactor culture system with Murashige and Skoog (MS) medium. Growth characteristics such as fresh weight, dry weight, length of shoots, and the number of nodes per shoot, length, and width of leaves were compared between cultures raised in bioreactor cultures and solid cultures. Shoots developed in bioreactor cultures showed higher values for these parameters than shoots grown in solid cultures. The leaf thickness and width of the upper epidermis, lower epidermis, palisade, and spongy tissues were also higher with shoots cultured in bioreactor cultures. Microscopic observation of the lower epidermal surface indicated that the stomata of leaves grown on liquid medium were normal and elliptical with narrow pores, whereas leaves grown on solid medium showed round, abnormal, and closed stomata. Studies on the optimization of the culture medium of bioreactor cultures were carried out. Of the varied strengths of MS media (0.5, 1, 1.5, and 2.0 x) tested, 2.0 x MS medium was found suitable for shoot cultures. Similarly, varied levels of ammonium (NH4+) and nitrate (NO3-) (20/100, 40/80, 60/60, 80/40, and 100/20 mM) were tested for the growth of shoots in bioreactor cultures; 20/100 mM ratio of NH4+:NO3- was found suitable. The results indicate that bioreactor cultures with modified MS medium could be used for mass propagation of Solanum tuberosum L. 'Yansi' shoots.