Variability of male gametophyte traits in morphological forms of <i>Taraxacum officinale</i> Wigg. s.l. under conditions of technogenic soil transformation

Abstract

The paper studies endogenous, individual and group variability of the traits pollen grain fertility and size of fertile pollen grains among two morphological forms of Taraxacum officinale Wigg. s.l., growing in coenopopulations in the gradient of technogenic soil transformation. The study area is the Pritagil zone of the Middle Urals (Nizhny Tagil city, Sverdlovsk Region, N 58, E 60). It was found that the studied morphological forms of dandelion in most cases are characterized by average endogenous, individual and group variability of the trait pollen grain fertility and low endogenous and individual variability of the trait pollen grain size. The group variability for this trait is medium and low. The endogenous variability of pollen grain fertility and size among f. dahlstedtii on agrozems is slightly higher than on technozems. Among f. pectinatiforme the endogenous variability of pollen grain fertility is higher on agrozems only. An increase in the level of soil contamination on agrozems leads to a decrease in the endogenous variability of pollen grain fertility among both forms of dandelion. On technozems a similar reaction is expressed only among f. pectinatiforme. The analysis of the studied trait in the entire gradient of technogenic soil transformation indicates a significant influence of this factor only on the endogenous variability of pollen grain fertility among f. dahlstedtii. Despite the absence of statistically significant differences in the individual variability of the pollen grain fertility trait between dandelion forms, on average, the coefficients of its variation on agrozems are lower among f. dahlstedtii, and on technozems among f. pectinatiforme. The same conclusion applies to the individual variability of the trait size of fertile pollen grains. In general, among f. dahlstedtii the coefficients of variation of the studied signs of the male gametophyte are lower in agrozems than in technozems, among f. pectinatiforme the picture is reversed. On average, the proportion of plants with low (Cᵥ 11%) individual variability in pollen grain fertility among f. dahlstedtii out of all the studied coenopopulations is 43,3% versus 61,7% among f. pectinatiforme. The influence of technogenic transformation of the environment is manifested in an increase in the proportion of f. pectinatiforme plants with a low level of variability of the studied traits in the coenopopulations of the buffer and impact zones. Among f. dahlstedtii the reverse pattern is characteristic only for pollen fertility. The group variability of pollen grain fertility in both agrozems and technozems is higher among f. dahlstedtii. With an increase in pollution on agro-soils, this indicator increases among both forms of dandelion, and decreases in technozems. There is a tendency to increase the group variability of pollen grain fertility among plants of both forms of T. officinale on technozems. An increase in the level of soil contamination on agrozems leads to an increase in the group variability of the trait size of fertile pollen grains among f. dahlstedtii and a decrease among f. pectinateforme. On technozems the opposite effect is noted. In general, the group variability of the studied trait among plants of both morphological forms of dandelion on agrozems is higher than on technozems.