THE EFFECT OF LEAD IONS ON THE GROWTH OF WHEAT, BARLEY, AND CUCUMBER SEEDLINGS

The responses of winter wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and cucumber (Cucumis sativus L.) seedlings to lead nitra te were studied as functions of lead rates (concentration and duration of treatment), seedling age, and the presence of other salts. An incr ease in the lead nitrate concentration from 10(-6) to 10(-2) M and tre atment duration from one to seven days resulted in greater inhibition of plant growth. The shoots were more tolerant to lead than the roots. The toxicity of lead nitrate was greatly reduced by the presence of o ther salts. The plant species studied showed species-specific quantita tive differences in their responses to lead ions with respect to plant age.