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COMPARISON OF THE ONION PLANT ( ALLIUM CEPA ) AND ONION TISSUE CULTURE
Author(s) -
TURNBULL A.,
GALPIN I. J.,
SMITH J. L.,
COLLIN H. A.
Publication year - 1981
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1981.tb03197.x
Subject(s) - callus , flavour , shoot , bulb , allium , tissue culture , botany , biology , chemistry , biochemistry , food science , in vitro
SUMMARY Tissue cultures of onion, differentiated into roots and shoots, were examined for total flavour precursor levels, composition of the flavour precursors and activity of the enzyme alliinase. Comparisons were made with undifferentiated callus and with the roots and shoots of germinating seedlings and shooting bulbs. Undifferentiated callus contained none of the major flavour precursor compound, 5‐trans‐prop‐1‐enyl‐L‐cysteine sulphoxide, but in the differentiated tissue this compound was present in both redifferentiated roots and shoots. In intact plants, more flavour precursor accumulated in rapidly growing roots and shoots. Onion bulb tissue and callus tissue from a long established cell clone and a newly initiated clone were examined under the electron microscope. The major structural component in the onion bulb cells, which was absent in the callus, was a larger number of vesicles in the cytoplasm and central vacuole. Since callus does not produce the onion flavour precursor compounds, possibly, in normal onion tissue, the vesicles are part of the flavour producing system, either as a store for the flavour precursors or for the degradative enzyme alliinase; in this way both parts of the system may be spatially separated until the tissue is damaged or cut.