Abstract
Single-node stem cuttings each with a leaf of potato (Solanum tuberosum L. cv. Benimaru) plantlets were cultured in vitro under photoautotrophic conditions for 24 days on full, half or quarter strength Murashige and Skoog liquid media (16 or 32 ml per vessel, or 4 or 8 ml per explant) in fibrous polyester cubes in 480-ml glass jars. The environmental conditions were 25 ±1°C air temperature, 7592% relative humidity, 12 mmol-mol-1 CO2 in the culture room during photoperiod, 16 hr•d-1 photoperiod, 170 μmol•m-2•s-1 photosynthetic photon flux density (PPFD), and number of vessel air exchange per hour of 1.4.
After 24 days of culture, fresh and dry weights, shoot length, number of leaves, leaf area, net photosynthetic rate per until leaf dry weight and relative growth rate per day of the plantlet were enhanced, while percent dry matter was suppressed, with increasing volume and initial strength of the medium.
The concentration of P in the medium was near zero g•m-3 on day 24 in all the treatments. The concentration of NH4 was also near zero g•m-3 except in the full strength with 32-ml medium after 24 days of culture. Uptake rate per plantlet gram dry weight of NO3, NH4, P, K, Ca and Mg over the 24-day period increased with increasing the volume and initial strength of the medium. Both the volume and initial strength of the medium, which affect the initial ion content, affected the growth, photosynthesis and ion uptake of potato plantlets in vitro over the 24 day period.
