The strategy of the genesis of the male generative sphere of the winter‐flowering shrub Jasminum nudiflorum Lindl. (Oleaceae) under the conditions of the Southern coast of Crimea

Abstract

Aim. Analysis of the dynamics of growth and development of anthers of the winter‐flowering shrub Jasminum nudiflorum in the conditions of the Southern coast of Crimea in connection with the determination of an adaptive strategy for the genesis of the male generative sphere of the species.Material and Methods.  The  stages  of genesis  of  Jasminum nudiflorum anthers were determined during the weekly analysis of temporary and permanent  preparations  of  buds  collected  from  June  to  December 2018–2020. The dynamics of the growth of anthers was determined by calculating the relative growth rate (R), based on the actual data of their lengths.Results. The genesis of J. nudiflorum anthers takes 6–7 months and is characterized by alternating periods of decreasing and increasing growth intensity. A high positive correlation was established between the lengths of J. nudiflorum anthers and their development stages (r=0,94). The premeiotic period lasts from the 2nd decade of June to the 3rd decade of August. In it, it is possible to distinguish the resting phase, which falls on the 3rd decade of July – I decade of August, after which the growth and differentiation of anther tissues is activated. During the period of microsporogenesis (1st – 2nd decades of October), the growth intensity reaches its maximum values. The average daily air temperature during this period is +16...+18°C. In the post‐arctic period (2nd decade of October – 3rd decade of December), when the differentiation of the gametophyte occurs, there is a decrease in the relative growth rate of anthers. In winter, the anthers are at the stage of vacuolated microspores, which can tolerate short‐term freezing without reducing the quality of pollen.Conclusions. The strategy of the genesis of the male generative sphere in the winter‐flowering shrub is characterized by alternating periods of increase and decrease of the intensity of their growth, which are timed to certain stages of development and seasons of the year and are adaptive in nature, aimed at reducing the influence of stress from meteorological and climatic factors, which is important for the production of a fertile gametophyte.