ABSTRACT
Potato (Solanum tuberosum L.) is a major global food crop. Contemporary potato production largely utilizes micropropagation to produce healthy seed potatoes. The micropropagation of potatoes is widely achieved through nodal explants using the conventional Murashige and Skoog (MS) medium. Currently, effective culture media that can facilitate rapid propagation are increasingly required for new cultivars that have been developed to possess improved traits. In this study, we evaluated the effect of enhanced meso nutrients (CaCl2.2H2O, MgSO4, and KH2PO4) in MS medium on the growth of S. tuberosum. The cultivars used in this study were representative of Japanese, European, and Peruvian lines. Enhanced meso nutrients improved the overall quality of all cultivars, as indicated by longer shoots and larger leaves with dark color, compared with MS medium only. Shoots grown on enhanced mesos were approximately 1.5 times longer than on MS medium. Quantitative ion analysis revealed that plantlets with improved shoot length and leaf quality in most cultivars had increased calcium, magnesium, potassium, and phosphorus uptake than plantlets on MS medium. The results suggest that the reduced iron uptake on 3.0×MS, compared with 2.0× or 2.5×MS mesos, reduced plant growth. This study revealed for the first time that mesos concentrations higher than MS medium concentrations, complemented by enhanced calcium, magnesium, potassium, phosphorus, and iron uptake, play a significant role in improving the in vitro growth of potato.
ABSTRACT
Natural seed germination is difficult to achieve in numerous plant species of wide economic importance. The germination of Polygonatum macranthum seeds takes as long as one and a half years under natural conditions. In addition, propagation by rhizome is also extremely slow in this species. Therefore, the natural propagation of P. macranthum through seeds or rhizome is not efficient. In this study, an efficient in vitro propagation system for P. macranthum from immature seeds with seed coat was developed, using a new surface sterilization protocol that utilized a low concentration of hypochlorite. In vitro germination was achieved at a rate of 30% within 9 weeks after inoculation on 1/2 MS medium. Shoot explants from seedlings were successfully cultured on 1/2 MS medium. Supplementation of the 1/2 MS medium with cytokinin 6-benzylaminopurine (BAP) facilitated efficient propagation by microrhizome. An efficient propagation rate of 1.3 microrhizomes per shoot in an 8-week culture period could be achieved by using a concentration of 1 mg l-1 BAP. During 4 weeks of acclimatization, 88% of shoots were rooted and started to grow into juvenile plants. After about 16 weeks in the field, 13% of the acclimatized plants showed viable growth and healthy regenerating shoots. The cultivation system demonstrated in this study can be used to propagate P. macranthum.
