Morphology, cytology and taxonomic remarks of four species ofStigeoclonium(Chaetophorales, Chlorophyceae) from Argentina

Abstract

Four species of Stigeoclonium from Argentina were studied by means of transmission electron microscopy and light microscopy. For species identification, we collected data related to the prostrate system and zoospore germination. We also determined the chromosome number for each species. Stigeoclonium aestivale showed a more developed erect system than the prostrate one, zoospore germination was predominantly of erect type and the chromosome number was 8. Stigeoclonium tenue presented well developed, erect and prostrate systems, zoospore germination was initially of the prostrate type and the chromosome number was 5. In Stigeoclonium variabile the prostrate system predominated over the erect one, zoospore germination was strictly of the prostrate type and the chromosome number was 3. Stigeoclonium farctum presented a more developed prostrate system than the erect one, zoospore germination was strictly of the prostrate type and the chromosome number was 8. The ontogeny of the zoospore germination was related to the final relative development of the prostrate and erect portions of adult thalli.

Discovery of two novel highly tolerant NaHCO3 Trebouxiophytes: Identification and characterization of microalgae from extreme saline–alkali soil

“…JB10 strongly resembled Stigeoclonium tenue in morphological description (Fig. 2j) [31]. Two symmetrical raphes of JB16 were present on both valves (Fig.…”

Karyological, morphological and phytochemical characteristics of medicinal plants Sophora flavescens Aiton grown from seeds collected at different localities

“…Several morphological characteristics (plant height, number of primary branches, seed weight and root dry weight) and the microscopic observations of root, stem and leaf tissues, as well as some phytochemical characteristics (total phenol, flavonoids, matrine, oxymatrine and antioxidant activity) of field-grown S. flavescens populations collected from different localities were compared. The karyological information is useful for in species identification and analysis of hybrid populations (Michetti et al, 2010; De Souza Almeida et al, 2007), and currently little information on karyotypes of the S. flavescens species is available even though it is reported to be a diploid (2n = 18) (Marhold, 2009). Therefore, attempts were also made to examine detailed karyotypes of the four populations.…”

A Comprehensive Study of the Life Cycle of a South American Population of Stigeoclonium Tenue (Chaetophorales, Chlorophyta)1

“…To date, there is only one study on a chaetophoralean alga ( Stigeoclonium helveticum ) that integrates morphological, cytogenetic, and life cycle data (Simons and van Beem 1987). There have been various studies on S. tenue , including one dealing with some aspects of its asexual reproduction (Michetti et al. 2002, 2010).…”

“…Species identification. The species was identified taking into consideration the morphology of both erect and prostrate vegetative systems together with the nature of zoospore germination and the characteristics of the subsequent thallus development (Michetti et al. 2010).…”

“…Zoospore germination was initially prostrate and immediately followed by the formation of the erect system (not illustrated). Zoospore germination and the subsequent thallus development have been recently documented (Michetti et al. 2010).…”