Ecotypes or phenotypic plasticity—The aquatic and terrestrial forms of Helosciadium repens (Apiaceae)

Abstract

Morphological and ecological differences of two forms of Helosciadium repens are known and described in the literature: aquatic and terrestrial. However, their taxonomic status is currently unknown. The question whether they are genotypically adapted to specific environmental conditions or are those differences a result of phenotypic plasticity is addressed in this study. SSR and ISSR data were used to uncover genotypic differences. Data from drought stress experiments (system water content and relative water content of leaves) were used to evaluate the response to water as an environmental factor. The stomatal index of both forms grown under different water treatments was analyzed. The principal component analysis of the ISSR data revealed no clustering that would correspond with ecotypes. The diversity parameters of the SSR data showed no significant differences. The aquatic populations showed a tendency toward heterozygosity, while the terrestrial ones showed a bias toward homozygosity. Both forms responded similarly to the changes in water availability, with newly produced leaves after drought stress that were better adapted to repeated drought stress. Stomatal indices were higher in plants from aquatic habitats, but these differences disappeared when the plants were grown in soil. The observed responses indicate that the differences between forms are due to phenotypic plasticity.

Genetic diversity of Helosciadium repens (Jacq.) W.D.J. Koch (Apiaceae) in Germany, a Crop Wild Relative of celery

“…Therefore, the set of MAWPs from BY also include two aquatic populations, which represent 40% of the BY candidates. Recently, Herden and Friesen () compared both forms genetically and morphologically and found no evidence for taxonomic division.…”

Functional Niche Partitioning Occurs over Body Size but Not Nutrient Reserves nor Melanism in a Polar Carabid Beetle along an Altitudinal Gradient

“…Selecting relevant traits to measure adaptive adjustments is also not an easy task, especially when effects can also be due to other physiological, chemical, or potential phylogenetic signals that may exist between morphotypes. Here, it is unlikely that the sole process in action would consist of the simple phenotypic expression of organisms in response to different environmental factors, as in the heterophylla of plants or the different colorations of domestic cats [ 5 , 74 , 75 , 76 , 77 ]. Our results thus suggest that the populations of A. pacificum sampled along the altitudinal gradient have been subjected to selection for given trait values, whereby having an increased body size and higher melanism at elevated sites seems to provide a phenotypic advantage.…”

Kruipend moerasscherm (Helosciadium repens) in Zeeland : ecologie en beheer van een Europees beschermde plantensoorten

“…De deelpopulaties raakten van elkaar geïsoleerd. Uit Duitsland is bekend dat sterk geïsoleerde populaties een verschillende genetische samenstelling hebben (Herden & Friesen, 2019).…”