Nucleic acid content and viability of the wheat seeds

Abstract

The viability of the wheat embryos is evidenced by: 

a) their capacity for germinating in a short time and to develop normal plantules,

b) the notable increase undergone by the DNA and the RNA during the germination,

and c) the ascending course followed by the DNA and the RNA in the plantules.

All these features are manifested the more conspicuously, the higher the level of the DNA and RNA in the seeds in repose.

It could admit the existence of a viability critical DNA level in the embryos in a State of rest. This level has been referred to the seed as a whole, in view of the difficulties attendant on the separation of the embryo and the endosperm when the seed is in repose; moreover, in view of the influence that inight be exercised by the endosperm on ambryonal germination. In wheat seed of recent crop this critical level we have found to be 54 ng per seed.

The DNA and the RNA of high viability degree embryos increase during germination, in very much higher proportion to their diminution in the endos­perm, thus indicating an independant synthetic formation in the former, apart from and in addition to that which migrates from the latter. The DNA and the RNA notably diminish in non-viable embryos, as does any other reserve substance.