Origin and Early Growth of Celery Embryoids

Abstract

SUMMARYSuspension cultures of celery emhryoids were initiated by transferring portions of differentiating callus to liquid medium. Light microscope studies of the cells and embryogenic aggregates in the suspensions suggested that the emhryoids arose from either single cells within the embryogenic aggregates, when the developing emhryoid remained attached to the clump until the globular stage, or from free floating small groups of cells. Both types of development showed the celery emhryoids to he of single eell origin. When the emhryoid suspension was filtered to remove the larger embryoids and the small emhryogenic aggregates and free floating embryoids were mixed with agar and plated, the development of the embryoids depended on the initial inoculum density. At low density further embryoid development was delayed while at the high inoculum density the emhryoids became green and grew rapidly into torpedo embryoids with cotyledon leaves and roots. At this stage they could be transferred to a simple inorganic medium to develop into plantlets. The effect of inoculum density was thought to be due to a conditioning effect of the environment. It is suggested that the differentiating units in the emhryoid suspension could be used in a cell selection procedure.

Somatic Embryogenesis and the Technology of Synthetic Seed

“…Celery somatic embryos required 5 weeks before forming roots and leaves (Dunstan et al 1982). After adequate growth was obtained, the plants were transferred to soil in propagation boxes in the greenhouse, then to individual pots.…”

Asulam Resistance in Embryoids of Celery Tissue Cultures

“…Herbicide resistant cell lines have been obtained but it is not always possible to regenerate plants from these (Aviv and Galun, 1977;Chaleff and Parsons, 1978). One method of overcoming this problem would be to use partially differentiated units in the selection procedure, rather than undifferentiated cells as suggested by Dunstan et al (1981). Embryogenic cultures such as those developed from carrot or celery would be the most suitable since the cultures would contain large numbers of embryogenic clumps, globular and torpedo embryoids (Halperin and Wetherell, 1964;Al-Abta and CoUin, 1978).…”

“…Embryogenic cultures such as those developed from carrot or celery would be the most suitable since the cultures would contain large numbers of embryogenic clumps, globular and torpedo embryoids (Halperin and Wetherell, 1964;Al-Abta and CoUin, 1978). There is also the possibility that all tissue culture embryoids are derived from single cells (Konar, Thomas and Street, 1972;McWilliam, Smith and Street, 1974;Dunstan et al, 1981), so each differentiating unit would be genetically uniform. The use of partially differentiated units in a selection programme for herbicide resistance was tested by exposing embryogenic celery cultures to the herbicide Asulam.…”