The Effect of an Increase in Light Intensity on the Utilization of Leaf Primordia in Osmunda cinnamomea L.

Abstract

Bud histories, that is, alternating sequences of bud scales and leaf bases remaining on the stem of the fern, Osmunda cinnamomea L., were determined in order to investigate the effects of an abrupt increase in light intensity on leaf primordial utilization. Studies of these increases in light intensity were made on plants growing under natural conditions. Increase in light intensity occurred in 1965 at the site of a newly developed road and also in 1968 at the site of a selective logging operation. Following an increase in light intensity, there is an increase in leaf primordial utilization. This increase occurs in both the bud scale and leaf fractions of the set. That these increases come from a large reservoir of leaf primordia that were initiated several years prior to their utilization indicates that they should be considered strictly as utilization events and not initiation events. Leaf initiation, however, increases as well.