ISHS Acta Horticulturae 440: International Symposium on Plant Production in Closed Ecosystems
GASEOUS AND MEDIA-RELATED FACTORS INFLUENCING IN VITRO MORPHOGENESIS OF JERUSALEM ARTICHOKE (HELIANTHUS TUBEROSUS) ‘NAHODKA’ NODE CULTURES |
| Authors: | T.D. Roche, A.C. Cassells |
| Keywords: | ethylene, gas-permeable films, hyperhydricity, micropropagation, shoot morphology |
| Abstract:
The influence of differentially permeable plastic film closures on microplant development, in vitro ethylene accumulation and calcium utilisation was investigated in nodal cultures of Helianthus tuberosus 'Nahodka'. In cultures sealed with lids having low water vapour transmission rates abnormal microplants developed. The main symptoms observed were shoot- and leaf-tip necrosis, basal callus proliferation and lenticel hypertrophy. Shoot and leaf-tip necrosis were found to be related to acropetal calcium deficiency and could be prevented by Ca-supplementation of the medium, by bottom cooling culture vessels or by using vessel closures with higher moisture vapour transmission rates. These treatments also reduced the incidence of basal callusing and promoted normal root development. Ethylene accumulation was highest in cultures with the lowest rates of water vapour transmission and was found to be related to the proliferation of basal callus and lenticel hypertrophy under these conditions. Ethrel stimulated similar symptoms in culture vessels fitted with higher moisture vapour transmission rates and exaggerated the effect of low moisture vapour transmission rates. These results suggest that the moisture vapour transmission rate of the culture vessel closure is a primary factor influencing ethylene-induced morphological defects in this system. These results are discussed with a view to further elucidating key microclimate and physico-chemical factors which frequently undermine efficiency and quality in conventional plant micropropagation systems. | |
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