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Further Observations on Ilex Embryoid Production

1978; Elsevier BV; Volume: 89; Issue: 1 Linguagem: Inglês

10.1016/s0044-328x(78)80026-9

0044-328X

Chao Hu, J.D. Ochs, Florecncia Mancini,

Growth and nutrition in plants

Embryos of Ilex aquifolium, a tree angiosperm, were excised at heart stage and cultured in Lnsmaier and Skoog agar medium lacking hormones and optional constituents. Embryoids developed from the cotyledons of cultured rudimentary embryos at different stages of embryonic development and also from the cotyledons of young seedlings. Embryoid producing capacity was demonstrated in all seven horticultural clones tested. The cotyledonal embryoids appeared to be initiated from tissue layers deeper than the epidermis. The embryoids, from heart to mature stages, were morphologically similar to the in vitro developed zygotic embryos. The coloration of the embryoids strongly suggested that rather than from a single initial cell, they were organized from cell clusters. Embryoid production potential of the cotyledon did not appear to decline after four consecutive subcultures. Three distinct types of embryoid-producing calli developed from some of these subcultures. Some of the light-grown embryoids developed anthocyanin and stopped further development. Embryoids without anthocyanin developed to the mature stage. Elongation of the embryoidal radicle would take place only after the embryoid had been excised from the mother tissue and cultured individually. Although most of the plantlets germinated from isolated embryoids were normal, certain plantlets contained light colored tissue sectors on their cotyledons. Before this potential cloning technique can be used at a commercial level for forestry, pomology and ornamental horticultural industries, techniques for inducing embryoid production from tissues of mature plant in a cell suspension culture must be developed.