“…Hybrid plants grown in solutions containing 4.0 milligram atoms of nitrogen per liter had medulla parenchyma cells in the third internode larger than those of either parent at the same level on the plant. Plumular meristem size in heterotic maize was found to be no greater than that of the larger parent while, in one pedigree, nuclear size in the plumular meristems of the hybrid was significantly greater than in the larger parent (Bindloss, 1938). Whaley (1939b) found no relationship between volume of the meristem and degree of hybrid vigor in the embryo or during development of tomatoes.…”