Laticifers in Camptotheca acuminata Decne: distribution and structure.

In this paper, a system of laticifers in Camptotheca acuminata Decne (Nyssaceae) is described. Laticifers were already present in the leaf primordia of the shoot apex. In the mature leaves, laticifers were found in the midrib and in the larger veins, both in the parenchymatic region delimited by vascular bundles and in the cortex just external to the phloem. In the stem, laticifers were present in both the primary and secondary body, running parallel to the longitudinal axis. They were located in the pith and in the cortex proximal to the phloem. No laticifers were found in the roots. The histochemical analyses indicated that the main compounds accumulated in laticifers were phenols. Neutral lipids and fatty acids were also present. Ultrastructural observations showed osmiophilic globules both in the vacuoles and in the peripheral regions of the cytoplasm of the laticifer cells. Plastids were present, although altered, with some parallel membranes and lacking starch grains. The discovery in C. acuminata of a laticifer system, which had never been described for the order Cornales, could be of taxonomic value, also considering that this order has traditionally represented one of the most problematic groups of flowering plants.