Establishment and physiological analyses of photoautotrophic callus cultures of the fern Platycerium coronarium (Koenig) Desv. under CO2 enrichmen

• Published in: Journal of experimental botany 1995-10, Vol.46 (10), p.1535-1542
• Main Authors: Kwa, Siew-Hwa, Wee, Yeow-Chin, Lim, Tit-Meng, Kumar, Prakash P.
• Format: Article
• Language: English
• Subjects: autofluorescence of chloroplasts; confocal laser scanning microscope; Fv/Fm ratio; photoautotrophic callus; Platycerium coronarium; stag's horn fern
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/46.10.1535

Gametophyte-derived callus cultures of Platycerium coronarium could be maintained under photoautotrophic conditions on Murashige and Skoog medium supplemented with 2μM 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 0.2≤ sucrose and no CO2 enrichment. Enriching the photoautotrophic cultures on 2μM 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 (>0.5%) than that on sucrose 1.0%. 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 decrease in photosynthetic capacity.