Abstract
It was found that triazine herbicides exerted, when applied for a longer time, an increasing inhibitory effect on dry and fresh weight yields, transpiration and growth of the seedlings of flax, beet and buckwheat. At the same time enhanced accumulation of free amino acids and decrease of simple sugar values was noted in the aboveground parts of the test plants. The results are interpreted as the secondary effects of the inhibitory action of triazines on plant photosynthesis. The toxicity of the tested chemicals to flax, beet and buckwheat decreased in the following order: atrazine, simazine, propazine, atratone, prometone and prometryne. Flax was more resistant to triazines than beets and buckwheat.