Effects of temperature, photoperiod and culture vessel size on adventitious shoot production of in vitro propagated Huernia hystrix

• Published in: Plant cell, tissue and organ culture Vol. 99; no. 2; pp. 233 - 238
• Main Authors: Amoo, S. O, Finnie, J. F, Van Staden, J
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.11.2009; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: adventitious shoots; ambient temperature; Apocynaceae; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; C3 photosynthesis; Crassulacean acid metabolism; culture media; culture vessel size; diurnal variation; endangered species; Explants; Fundamental and applied biological sciences. Psychology; Germplasm; Growth rate; Huernia hystrix; Hystrix; in vitro regeneration; Life Sciences; Low temperature; medicinal plants; Micropropagation; Optimization; Organic acids; organic acids and salts; Organic chemistry; photoperiod; Photosynthesis; Plant Genetics and Genomics; plant growth; Plant Pathology; Plant Physiology; Plant Sciences; Production costs; Research Note; Shoots; Temperature; Temperature effects; Tubes; Vessels; Culture container; Tissue culture; Environmental factors; Micropropagation; CAM; Succulent; Culture medium; Vegetals; Adventitious bud; Size; Temperature effect; Container growing; Environmental factor; Photoperiod; Microplant; Succulent plant; Production
• ISSN: 0167-6857; 1573-5044
• DOI: 10.1007/s11240-009-9592-0

High production costs due to low growth rate in vitro and high labour costs are among factors limiting commercial application of micropropagation techniques. The low growth rate could be due to unfavourable or sub-optimal environmental and chemical conditions of the cultures. The effects of temperature, photoperiod and culture vessel size were investigated on adventitious shoot production of Huernia hystrix. There were significant increases in shoot proliferation with increased temperature in cultures maintained under a 16 h photoperiod. Slow growth observed at low temperatures (15 and 20°C) offers a potential strategy for cost-effective in vitro storage of H. hystrix germplasm. The maximum adventitious shoots produced per explant and percentage of explants producing shoots (4.2 ± 0.74 and 94% respectively) were observed in cultures maintained at 35°C, the optimum temperature for photosynthesis in plants possessing crassulacean acid metabolism (CAM). The nocturnal accumulation of organic acids in cultures incubated under a 16 h photoperiod further suggest the presence of CAM in this species. On the other hand, cultures kept under continuous light appear to shift to a C-3 photosynthetic pathway. There was a significant decrease in fresh weight of adventitious shoots regenerated per explant as temperature increased. The use of larger culture vessels further increased the shoot proliferation to 5.6 shoots per explant with a potential production of 3,429 shoots per m² in the growth room compared to 2,750 shoots per m² using culture tubes.