ABSTRACT

The tolerance of higher plants to herbicides seems to resemble that to air pollutants. It influences the tolerance of some weeds to paraquat, affecting how much of the herbicide they absorb into leaves. Plant tolerance to herbicides is intimately related to the mode of action of the herbicide. To clarify the tolerance mechanism of higher plants to environmental stresses, it is very important to know how plants are damaged by environmental stresses. The final tobacco plants had a greater tolerance to paraquat and a higher superoxide dismutase content than the control plants. Many workers have a great interest in determining whether high tolerance to air pollutants may be found in plants which are genetically enriched in active-oxygen-scavenging enzymes. Higher plants suffer severe damage from air pollutants. Typical injuries are bleaching of leaves and inhibition of photosynthesis. Most investigators have been interested in clarification of these phenomena.