SEASONAL RHYTHM OF INTRODUCED HAWTHORN SPECIES DEVELOPMENT IN MARI EL REPUBLIC

Abstract

The study of growth and development regularities of introduced species in new ecological conditions is of great importance for exotics availability evaluation. Knowledge of a specific seasonal rhythm gives the main ideas about exotic species relation to new living conditions and allows to  understand how complete is the matching of the phases of their growth and development to the local climate, weather and soil conditions. The purpose of the research was to reveal the regularities of seasonal development of introduced hawthorn (Crataegus L.) in ex situ culture in Mari El Republic. The task in hand was to analyze weather conditions of vegetative periods during observation period, to reveal peculiarities of  changing  of plants seasonal development phases depending on effective temperatures accumulation dynamics, to make a comparative analysis of the dates of  phenological phases changes  by the genus complex representatives. The objects of the research were the plants of 23 introduced hawthorn species of the Arboretum collection at the Botanic Garden-Institute of Volga State University of Technology (Yoshkar-Ola, Mari El Republic). Phenological observations were carried out  in 2005 - 2010 years in accordance with the technique of the Main Botanic Garden of the Russian Academy of Sciences for botanic gardens. The characteristic of weather conditions was provided according to BGI meteorological post. All data were processed by mathematical statistics methods. Species were divided by criterion хср.±σ into the early, average and late ones by the studied phenophases. All 23 studied introduced hawthorn species pass a full cycle of seasonal development in the Mari El Republic conditions. The sequence of phenological phases passing is as follows: buds breaking, beginning of shoots growth and leaves isolation, flower budding, beginning of shoots wooding, completion of shoots growth, beginning of flowering, completion of leaves growth and maturing, completion of flowering, fruits formation, completion of shoots wooding, fruits maturing, leaves coloration, leaves fall. A consecutive line of hawthorn species depending on the dates of seasonal development (from early to late) was made with the use of calculation of phenological distances and looks as follows: C. sanguinea, C. maximowiczii, C. nigra, С. chlorosarca, C. douglasii, C. pinnatifida, C. rivularis, C. almaatensis, C. chlorocarpa, C. arnoldiana, C. monogyna, C. punctata, C. chrysocarpa, C. grayana, C. volgensis, C. flabellatа, C. turkestanica, C. pringlei, C. horrida, C. submollis, C. macracantha, C. prunifolia, C. calpodendron. Close correlations were found between separate phenophases. The factor of year weather conditions has the greatest impact on development of vegetative bodies at the beginning of vegetation. A species specificity factor has the greatest  value at the end of vegetation. This factor has also the greatest impact on development of generative bodies (its influence increases in the course of phenophases passing by plants). Importance of year weather conditions factor, on the contrary, decreases by the end of a vegetative period.