Effects of Non-Ionizing Radiation on Expansion of Disks From Leaves of Dark-Grown Bean Plants

Abstract

The effects of and interactions of visible and untraviolet radiant energy on the expansion of disks cut from the primary leaves of dark-grown bean plants were investigated. Blue and red light were equally effective; both were negated by far red light Blue and red light interact in inducing expansion of disks when presented simultaneously or sequentially. Polarization of blue, red, or of far red light in any plane relative to the leaf surface increased the effectiveness of the radiant energy by 1 order of magnitude. Ultraviolet radiations induced leave expansion not under phytochrome control. Leaf disk expansion induced by any of the above radiations was due primarily to cell division.