Effect of nitrogen concentration on endosperm DNA content and cell number in wheat ears grown in liquid culture

Endosperms from grains from wheat ears grown in liquid culture at high N concentrations commencing at 7 days post-anthesis attained cell numbers within 90% of those obtained by grains from intact plants of comparable age. The endosperm DNA content of grains f~om cultured ears increased as the nitrogen concentration increased in the culture medium. Cell numbers, however, were only significantly affected when the cultured ears were deprived of exogenous nitrogen. The increase in endosperm DNA content as nitrogen concentration in the culture medium increased is explained by endoreduplication of nuclear DNA, a phenomenon previously observed in the aleurone of some other cereals.