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ARS Home » Midwest Area » East Lansing, Michigan » Sugarbeet and Bean Research » Research » Publications at this Location » Publication #58551

Title: ETHYLENE INHIBITORS ADDED TO IN VITRO CULTURE MEDIA OF COMMON BEAN PROMOTESMORPHOGENESIS OF COTYLEDONARY NODE EXPLANTS

Author
item HOYOS, R - MICHIGAN STATE UNIVERSITY
item Hosfield, George

Submitted to: Bean Improvement Cooperative Annual Report
Publication Type: Other
Publication Acceptance Date: 2/9/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Ethylene is a naturally occurring gas that is often produced by a plant after it is wounded or by the ripening fruits. Although ethylene causes fruits to ripen, this gas may cause growth inhibition of plant shoots cultured in glass dishes because it causes shoot tissue to prematurely age. Ethylene is a powerful inhibitor of plant growth and development of common bean clones (many identical copies of a plant) cultured in glass dishes. Ethylene is found in glass dishes containing bean clones because the tips are cut from shoots, thus, causing a wound. Although ethylene can be removed from glass culture dishes by sealing them with a porous tape which permits free exchange of gases within and outside the dish, small amounts of ethylene remain in the air inside the dish and exert inhibitory effects on shoots from ethylene sensitive bean varieties. An experiment was conducted in which a chemical that blocks the plant's ability to produce ethylene when wounded was added to the growth medium. A control medium was used in which the "blocking" chemical was absent. In the glass dishes containing the chemical, many new shoot were produced from the original shoot-tip. Even the most sensitive bean varieties produced numerous shoots in the presence of the "blocking" chemical. However, shoot growth was inhibited in the dishes without the chemical. The removal of ethylene from cultures with the use of chemicals that blocks the plants ability to produce the gas is useful for producing numerous and vigorous bean clones in glass dish culture.

Technical Abstract: Plant tissues cultured in vitro release ethylene which inhibits morphogenesis of explants into the atmosphere of culture vessels. The supplementation of culture media with chemicals that inhibit ethylene enhanced the regeneration of whole plants from explants of recalcitrant Brassica species. Common bean (Phaseolus vulgaris L.) is recalcitrant to in nvitro regeneration of plants from various explant tissues. Although structures resembling somatic embryos can be produced from bean callus, the embryos fail to develop into whole plants. Ethylene may be involved. The objective of the research was to investigate the role of ethylene on morphogenesis and shoot development of common bean cotyledonary node explants cultured in vitro. Explants were taken from 5-7 day old seedlings of 'Seafarer' navy bean, 'Jampapa' black bean, 'UI-114' pinto bean, and 'Colorado de Tapiosca' red bean. Explants were cultured on a MS basal medium supplemented with BAP and sucrose and solidified with phytagel. The ethylene inhibitors, silver nitrate and aminoethoxyvinyl-glycine were added to media at several concentrations. The control vessel contained 0.19 ppm ethylene and organogenesis and shoot development were infrequent and of poor quality. Organogenesis and shoot development were improved in the quality of buds and shoots produced compared to the control when explants were cultured on media containing ethylene inhibitors. Exogenous ethylene (Ethrel) added to media at all concentrations inhibited organogenesis and shoot development. The results of these experiments suggest that ethylene inhibits in vitro morphogenesis of common bean. The removal of ethylene from cultures via inhibitors may overcome the recalcitrance of common bean to regenerate plantlets from somatic embryos.