The pH-related morphological variations of two acidophilic species of Desmidiales (Viridiplantae) isolated from a lowland peat bog, Czech Republic

Abstract

Morphological variation related to pH was investigated in two acidophilic desmid species (Euastrum binale var. gutwinskii and Staurastrum hirsutum) utilizing geometric morphometric methods. Clones isolated from acidic habitats were cultured using a range of pH values from 3.5 to 6.5. The plasticity of ensuing populations was quantified and illustrated by the general Procrustes superimposition of landmarks placed along the outline of cells and subsequent statistical analyses of shape data. In both species, there was a significant effect of pH on the morphology of cells. In Staurastrum hirsutum, the pH-related morphological change was accompanied by a decrease in the size of cells cultured at a higher pH. However, in Euastrum binale, cell size did not differ in relation to pH, but cell shape was characterized by a deepening of the incisions between cell lobes at higher pH. In both species, cell complexity based on surface-to-volume ratio was positively correlated with increasing pH. We conclude that by manipulating their surface-to-volume ratios, these desmid species can respond to pH variations in their environment.

DNA Content Variation and Its Significance in the Evolution of the Genus Micrasterias (Desmidiales, Streptophyta)

“…Some strains come from the personal collection of Jiří Neustupa [39] ( Table 1 ). They were grown in 50 mm plastic Petri dishes in a liquid oligotrophic medium used in the CAUP culture collection (OGM; [45] ). Storage cultures were kept at a temperature of 16°C, under an illumination of 20 ìmol.…”

Molecular evidence for the polyphyletic origin of low pH adaptation in the genus Klebsormidium (Klebsormidiophyceae, Streptophyta)

“…The limited data available indicate that pH conditions may play a major role in this regard: Novis (2006) highlighted a strong effect of pH on the morphologies of K. acidophilum and K. dissectum, showing that characters such as cell shape, chloroplast shape and amount of granules deposited in the cytoplasm varied considerably in different pH conditions. Variations in pH are also known to affect cell shape in other green microalgae, mainly determining an overall reduction of the cell surface relative to the cell volume (Coesel 1982, Černá & Neustupa 2010. This phenomenon is considered a functional response aimed at reducing osmotic stress.…”

“…This phenomenon is considered a functional response aimed at reducing osmotic stress. Algae living in low pH habitats are able to maintain a fairly constant, neutral, cytosolic pH over a wide range of external pH values (Gerloff-Elias et al 2005, Bethmann & Schönknecht 2009; the maintenance of a neutral cytosolic pH under low pH conditions is an energy-demanding process that involves considerable metabolic costs, and a reduced cell surface contributes to reducing these costs (Černá & Neustupa 2010). Due to lack of experimental data, we are not able to demonstrate similar effects in our Klebsormidium strains and to assess their morphological variation in different pH conditions; we expect, however, that variations similar to those reported by Novis (2006) are probably general phenomenon.…”

Effect of temperature on size and shape of silica scales in Synura petersenii and Mallomonas tonsurata (Stramenopiles)

“…Multivariate regression of shape data with temperature as the independent variable was then performed. To determine the effect of temperature on shape, with size-effect controlled, the allometric shape variation was separated (Debat et al, 2003;Č erná & Neustupa, 2010). First, we performed a multivariate regression of shape data on the centroid size (CS) of the scales.…”