Showing papers by "Debra Mohnen published in 1990"

The control of root, vegetative shoot and flower morphogenesis in tobacco thin cell-layer explants (TCLs)

Abstract: Thin cell-layer explants (TCLs) have been proposed as favorable tissues for the study of root, vegetative shoot and flower formation. We tested the effects of pH, light quality, light quantity, and IBA and kinetin concentrations on the morphogenesis of TCLs cultured individually on a liquid medium. Alterations of the amounts of exogenously supplied IBA and kinetin were sufficient to induce the formation of roots, vegetative shoots and flowers on TCLs cultured on otherwise identical media. The type and number of organs formed were sensitive to the intensity of light (55, 75, 100 and 120 muEinsteins m-2 sec-1) under which TCLs were grown. Evidence was obtained that the effects of light on TCL morphogenesis were associated with photochemical degradation of IBA in the medium. Evaluation of the organogenesis that occurred in TCLs cultured on a medium containing a range of IBA and kinetin concentrations showed that the number and type of organs formed, and overall growth, were dependent upon the initial concentrations of auxin and cytokinin. We have developed the TCL culture system into a sensitive and reproducible bioassay for the study of morphogenesis. The advantages of using the TCL morphogenesis bioassay for the identification and study of molecules (e.g. cell wall oligosaccharides) that may regulate morphogenesis are discussed.

Asssay for molecules affecting plant morphogenesis

Abstract: A plant thin-cell-layer (TCL) culture system has been developed to study root, vegetative shoot, and flower morphogenesis. The effects of hormone concentrations, pH, and light quality and quantity on TCL morphogenesis were analyzed. Roots, vegetative shoots, and flowers formed on TCLs cultured on various liquid media that had been adjusted to the same pH. Evidence is presented showing that the effects of light on TCL morphogenesis are associated with light-mediated degradation of indol-3-butyric acid (IBA) in the medium. Evaluation of the organogenesis that occurred in TCLs cultured on a range of IBA and kinetin concentrations revealed that the quantity and type of organs formed were dependent upon the concentration of IBA and kinetin in the medium. The TCL assay system is useful for studies of the molecular changes associated with organogenesis and for the screening, identification, and purification compounds capable of affecting plant morphogenesis.