Establishment and physiological analyses of photoautotrophic callus cultures of the fern Platycerium coronarium (Koenig) Desv. under CO2 enrichment
1995
Kwa, S.H. | Wee, Y.C. | Lim, T.M. | Kumar, P.P.
Gametophyte-derived callus cultures of Platycerium coronarium could be maintained under photoautotrophic conditions on Murashige and Skoog medium supplemented with 2 micromolar 2,4-dichlorophenoxyacetic acid (2,4-D) and with CO2 enrichment. Progressive reduction of sucrose from the medium resulted in a reduction in growth, but an increase in total chlorophyll content. When subculturing was delayed beyond 2 weeks, callus cells differentiated into gametophytes on the medium with less than or equal to 0.2% sucrose and no CO2 enrichment. Enriching the photoautotrophic cultures on 2 micromolar 2,4-D with 1% CO2 resulted in about 1.7-fold increase in fresh weight within 42 d. Total chlorophyll content was generally higher with 1% CO2 enrichment than with 10%. Fv/Fm ratio was higher for callus on low levels of sucrose (less than or equal to 0.5%) than that on sucrose 21.0%. An increase in autofluorescence of chloroplasts, but not the size, was observed with decreasing sucrose levels in the medium. Autofluorescence decreased with increase in CO2 from 0.03%. Our data are in agreement with the view that long-term exposure to high levels of CO2 can cause a decrease in photosynthetic capacity.
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