Phenotypic plasticity of Stratiotes aloides L. (Hydrocharitaceae)
The purpose of the research was to determine the diversity of Stratiotes aloides L. specimens in lake populations. The research material was collected from 6 Polish lakes and from five depths in each lake. A total of 19 qualitative and quantitative features of S. aloides were examined. The modified Shannon-Wiener index of S. aloides for six lakes and the analysed means, minimums and maximums were calculated, ANOVA analysis of variance for 6 lakes and 5 depths, the percentage increase for specimens between various levels was calculated, PCA analysis was performed, and the correlations between the examined features were discovered. S. aloides in Polish lake populations demonstrates high and very high diversity, which was confirmed by the overlapping scopes of quantitative features at individual depths and different values of quantitative features at the same depths in different lakes. S. aloides forms specimens with various numbers of emergent, submerged and arched leaves, depending on the degree of the specimen immersion in water. S. aloides have been found to have the smallest variation coefficient at depth 1-2 m. At any other depth, the variation coefficient is greater. Changing the depth results in increased coefficient variation. It is also disclosed that emergent leaves appear at level 0.5-1 m, while leaves that form deeper are submerged leaves. Studies have shown that lake populations of Stratiotes aloides form individuals with different numbers of emergent and submergent leaves, and not only in two forms.