Use of an (n, α) nuclear reaction to study the long-distance transport of boron in trifolium repens after foliar application.

The growth of white clover (Trifolium repens L.) is severely inhibited by boron starvation, but a foliar treatment with boric acid can transitorily alleviate the deficiency symptoms. The (10)B(n ,α)(7) Li nuclear reaction has been used to study boron transport in the plant after foliar application. More than 98% of the boron supplied remained at the point where it was applied to the leaves, and less than 2% was useful to the growth of the treated plant. This small "efficient" portion of boron was quite mobile. It was distributed to the different parts of the plant, then was transferred from the oldest parts to the newly formed leaves. Physiological and agronomical implications of these data are discussed.