The Effect of Growth in D2O on the Metabolism of Winter Rye

The metabolism of winter rye seedlings (Secale cereale, L. ev.Winter) cultured in 99.8 per cent D₂O was investigated. Comparedwith water-grown seedlings, the protein content was much lowerin the D₂O-cultured seedlings and the pattern of incorporationof [³H]leucine and [³H]phenylalanine into protein was substantiallydifferent. Seedlings cultured in D₂O incorporated [³H]thymidineinto DNA, but did not take up [³H]uridine. The results suggestthat some of the toxic effects of D₂O culture on higher plantscan be attributed to a partial block of protein synthesis.     

Changes Induced in Peroxidase Activity under Simulated Hypo-gravity

A new method of inducing and maintaining a hypo-gravity environment is described. Using this new technique (buoyancy compensation), the effect of reduced gravitational stress on dwarf marigolds (Tagetes patula) was studied. It was found that the specific activity of peroxidase was elevated significantly in gravity compensated seedlings. This effect, discovered with the buoyancy compensators, was confirmed with plants grown on traditional clinostats.