A possible role for boron in higher plants

Abstract The influence of boron on flavonoid metabolism in leaves of tomato plants (Lycopersicon esculentum Mill, cv. Marglobe) was investigated. A significantly higher rate of total flavonoid was observed from a B‐deficiency in the nutrient medium. This effect was noted during the last periods of culture cycle. On the other hand, B deficient leaves showed a total absence of flavonols usually present in this tissue. The qualitative differences among various levels were a higher flavone: flavanone ratio, whereas B excess treatment shows the opposite effect. These results suggest a role for B in higher plants as a regulator of flavonoid biosynthesis.