Variability Of Morphological Features Of Needle Juniperus Excelsa M.-BIEB. In Mountain Crimea

In the course of the studies, within the population of J. excelsa in the Crimean Mountains, 2 types of needles were identified: scaly and acicular. Most individuals (81%) have scaly species-specific needles, which are of two types – green and glaucous. It has been established that the tip of the needles of J. excelsa can be of several types – entire pointed, serrated and forked. The degree of bifurcation varies from narrowly bifurcated (divergence angle up to 5°) to widely bifurcated (angle – 30°). With the same frequency, these tip shapes are found in both scaly and acicular needles. In order to identify the adaptive ability of the vegetative organs of J. excelsa, an integral indicator was calculated – the total area of the assimilating apparatus. It was revealed that the western part of the range is characterized by a two times smaller total area of the assimilating apparatus than the southern and eastern parts, where this figure is 99.87 мм2. These territories turns to be the closest in terms of soil and climatic conditions to the main Mediterranean part of the range. Acicular needles are more susceptible to external factors than scaly needles. As a result of assessing the degree of leafiness of the shoot with acicular needles, a significant inverse relationship (r = −0.32) on its length was established, which was not the case for the scale-like needles of J. excelsa. The indicators of shoots leafiness of individuals of the western and eastern groups differ by two times. The strength of the influence of the regional factor is the maximum value for the needles of J. excelsa – 69.63%. In general, the acicular type of needles shows much more adaptive features, as a result the total area of the assimilating apparatus increases. Thus, the acicular needles of J. excelsa can be considered as one of the mechanisms of adaptation to soil and climatic conditions at the northern border of the range.

, , acicular needles, scaly needles, needle tip, Crimean Mountains, abiotic factors, adaptation