Images
Taxonomic characters
- can be distinguished from V. spermatosphaera by its larger gonidia, and from V. tertius by visible differences in gonidial chloroplast morphology (Nozaki and Coleman 2011)
- molecular phylogenetic analyses of the five chloroplast genes and the internal transcribed spacer (ITS) regions of nuclear rDNA indicated that
V. ovalis is closely related to Volvox spermatosphaera and ⁄ or Volvox tertius (Nozaki and Coleman 2011)
- belongs to the section Merrillosphaera
Morphology / Structure
- ovoid or elliptical, with an expanded anterior region
- 1,000–2,000 somatic cells that are not linked by cytoplasmic bridges
- 8–12 gonidia in the posterior region (gonidia measure 50–55 lm in diameter)
- no visibly asymmetric cleavage divisions (gonidia of the next generation are not recognizable embryos prior to inversion) (Nozaki and Coleman 2011)
Life history
- sexual spheroids could not be observed
Ecology
- isolated from a pond near College Station, Texas.
Availability in culture collections or research labs
Media and growth conditions in culture
Nozaki and Coleman 2011:
"The culture was at first maintained in media lacking major organic compounds [e.g.,C medium (Ichimura 1971, Kasai et al. 2009), AF-6 medium
(Kato 1982, Kasai et al. 2009)] because of bacterial contamination. After isolating unhatched juvenile spheroids from the parent by a micropipette to remove the contaminating bacteria, the culture was maintained in VTAC medium (modified Volvox medium; Nozaki et al. 1989, Kasai et al. 2009). "
"The cultures were grown in screw-cap tubes (18 · 150 mm) containing ca 11 mL medium at ca 25C on a 14:10 light:dark schedule under cool-white fluorescent lamps at an intensity of 110–150 umol/m2/s."
Sequence Information
Links to other databases
Miscellaneous
The strain ‘‘Volvox ovalis’’ was established by Dr. Elenor R. Cox (Texas A&M University), using a water sample collected
in a pond near College Station, Texas, sometime before 2000 (Nozaki and Coleman 2011).
Selected References
A NEW SPECIES OF VOLVOX SECT. MERRILLOSPHAERA (VOLVOCACEAE, CHLOROPHYCEAE) FROM TEXAS
Author(s): Nozaki H, Coleman AW
Source: JOURNAL OF PHYCOLOGY Volume: 47 Issue: 3 Pages: 673-679 Published: JUN 2011
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