Microscopic observation of pyrenoids in Order Ulvales (Chlorophyta) collected from Qingdao coast

Abstract

Pyrenoids found in green algae Order Ulvales have taxonomical significance. Their morphology, microstructure, and the location and number in the cells have been widely used as identification criteria. As these traits can be affected by environmental conditions, it is necessary to look for other different characteristics. Here pyrenoids in several algae species collected along the Qingdao coast were studied for such purpose. The morphology and distribution of pyrenoids in the cells, as well as their change in different parts of the frond and at different times were studied with light microscope. The results are as follows. Pyrenoids appeared to be spherical or oval in observed Ulvales' algae cells. They were embedded in chloroplasts with the number of 1−3 per cell on average. The number of pyrenoids for Ulva pertusa could change drastically with continuing culture and could reach up to 10−20 per cell in late-growth stages. Generally, the pyrenoids in the marginal part were more observable than those in the central part for Ulva pertusa. In addition, the basal part of frond had more distinct pyrenoids with an average diameter of 2.42 µm for Enteromorpha linza. For some species the pyrenoids were difficult to be observed while dark treatment made them more distinguishable. The apoptosis rate of pyrenoids in different species varied under continuing dark treatment, which could be used to identify different species. Pyrenoids disappeared faster in E. linza than those in E. intestinalis.

Ulva flexuosa subsp. pilifera (Chlorophyta, Ulvophyceae) from the Wielkopolska region (West Poland): a new observation on the ultrastructure of vegetative cells

“…Chloroplasts in Ulva cells from the Malta Reservoir, containing up to 4 pyrenoids, are similar to thalli described from other freshwater locations. Griffiths (1970) and Teng et al (2011), paid particular attention to the number of pyrenoids per cell as an identification feature. It appears that the number of pyrenoids as a criterion for the classification of algae is of rather limited value due to difficulties with effective examination of pyrenoids under a light microscope (apex cells are often too small to observe the presence or absence of pyrenoids).…”

Morphological and ultrastructural studies on Ulva flexuosa subsp. pilifera (Chlorophyta) from Poland

“…The chloroplasts in Ulva cells, from our samples were similar to the chloroplasts in the thalli from other freshwater sites, which have been found by other authors to contain up to four pyrenoids. The number of pyrenoids per cell has been treated as a distinctive feature for identification by Griffiths [17] and Teng et al [35]. The applicability of this criterion, however, appears to be rather limited on account of the difficulty with which the pyrenoid can be effectively investigated with a light microscope (i.e.…”

Diversity of CO2 Concentrating Mechanisms in Macroalgae Photosynthesis: A Case Study of Ulva sp.

“…CCM increases the concentration of CO 2 near Rubisco using an inorganic carbon pump, the synergy of one or more CA, and the packaging of Rubisco into pyrenoid [53]. Pyrenoids are found in almost all algae except Chrysophyta [53] and are relatively rare in algae with thallus but have been observed in Ulva, Monostroma, and Porphyra [54,55]. Some algae lacking pyrenoid increase the acquisition of CO 2 by acidifying the extracellular environment, effluxing active protons, or exporting CA to periplasm [56].…”