Histological changes in the structure of one-year sprouts of Pinus sylvestris L. as a reflection of the structural adaptation of the species during its introduction

Abstract

Comparative anatomical studies of one-year sprouts Pinus sylvestris L. made it possible to obtain data on the features of vegetative organ formation, histological changes and the persistence of structural features by the influence of environmental factors. It is noted that the parameters of histological structure and cytological indexes of one-year sprouts are strongly influenced by the hydrothermal coefficient (HTC) of growing conditions. The structure of the one-year sprouts of Pinus sylvestris L., growing in sufficient humidification (HTC=1.6) conditions, is characterized by the greatest thickness of cortex, phloem and xylem, the largest radius of pith, the maximum diameter of resin canals, while having the smallest size of external protective tissues. Histological studies of the geographical cultures of Pinus sylvestris L. of the central forest-steppe revealed, that being in the same growth conditions, the anatomical structure of one-year sprouts significantly changes. Histological and cytological indexes of the anatomical structure of the one-year sprouts of Pinus sylvestris L. populations from the dry steppe increase by 33%, from the broad-leaved forest zone decrease to 30%. Thus, structural adaptation of the assimilation apparatus to new growing conditions occurs, which determines in general the productivity and stability of the woodlands of Pinus sylvestris L.