Spring Shoot Growth in Douglas-Fir May Be Initiated by Gibberellins Exported from the Roots

Abstract

Plant cell membranes were examined in thin sections by electron microscopy. Numerous membrane continuities appeared between chloroplasts and other organelles of the fern Pteris vittata L., and occasionally in the leaves of the tomato Lycopersicon esculentum Mill. A number of these continuities had not been reported earlier or had been seen only infrequently.