Amino Acids as Sources of Nitrogen for the Growth of Isolated Oat Embryos

Brown (I906) has described the results of an early investigation on the ability of mature, isolated cereal embryos to utilize organic forms of nitrogen. He reported that ammonium sulphate, aspartic acid, glutamic acid, potassium nitrate and asparagine, at concentrations supplying equivalent quantities of nitrogen, showed progressive increases in their capacity to increase the dry weight and nitrogen content of barley embryos cultured for a period of one week. Out of these nitrogen sources only asparagine produced an increase in the growth in length of the roots, while all, with the possible exception of ammonium sulphate, produced an increase in the length attained by the shoot system. Phenylalanine, tyrosine and leucine were distinctly inhibitory to growth. So far as the author is aware, there have been no other recent reports of comparable studies on the ability of isolated cereal embryos to utilize organic forms of nitrogen for growth. The purpose of the present investigation was to assess the value of amino acids as sources of nitrogen for the growth of mature oat embryos isolated from their endosperm. Particular attention has been given to interactions occurring between amino acids in their effects on the growth of the embryos. A note on some of the experiments described has appeared elsewhere (Harris, I953a).