TIME COURSE SIMULATIONS OF CO2 CONCENTRATION AND NET PHOTOSYNTHETIC RATES OF POTATO PLANTLETS CULTURED UNDER DIFFERENT LIGHTING CYCLES

摘要

Potato (Solanum tuberosum L. cv. Benimaru) plantlets were cultured under four lighting cycles with the same ratio of photo/dark period (16 h/8 h, 4 h/2 h, 1 h/0.5 h, and 0.25 h/0.125 h) photoautotrophically (without sugar in the medium) and photomixotrophically (with sugar in the medium) in vitro for 28 days. Simulations of time courses of CO2 concentration in the vessel (Ci) for plantlets cultured photoautotrophically and photomixotrophically and dry weight accumulations of the plantlets cultured photoautotrophically were conducted using the same model and parameter values as those in Niu and Kozai (1997). While underestimation and overestimation of the time courses of Ci in some treatments were observed, the simulated values of Ci and the dry weight accumulation of the plantlets generally agreed with the measured values. The simulated responses of net photosynthetic rate of the plantlets to Ci indicated that in the early culture period, plantlets have higher photosynthetic ability under photoautotrophic than under photomixotrophic culture conditions. The quantitative relationship between daily net photosynthetic rate (daily net production) and vessel ventilation rate per plantlet was simulated under various CO2 levels outside the vessel for given sizes of potato plantlets cultured in vitro photoautotrophically to aid appropriate CO2 enrichment and vessel design in commercial micropropagation systems.