25.12.2013 Views

Download (3398Kb) - ePrints Soton - University of Southampton

Download (3398Kb) - ePrints Soton - University of Southampton

Download (3398Kb) - ePrints Soton - University of Southampton

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

and the data were presented as histograms with mean and standard deviation for each<br />

stage <strong>of</strong> development. Zygotes looking normal with fertilization membranes but no<br />

cleavage were classified as uncleaved. Embryos with irregular cleavage or with blebs<br />

in the cytoplasm were classified as "abnormal" (Fig. 3.6).<br />

250 µm<br />

Fig. 3.6. Embryos <strong>of</strong> Marthasterias glacialis (Linnaeus) that underwent irregular<br />

cleavage and two zygotes that remained uncleaved after 48 h <strong>of</strong> being cultured at 200<br />

atm and 20° C. (Micrograph by Francisco Benitez)<br />

3.2.3- Temperature/pressure effects on larvae.<br />

Embryos were cultured for 20-30 days at 15 o C and 1 atm until they became<br />

swimming bipinnaria. Three replicate cultures <strong>of</strong> larvae were subjected to each <strong>of</strong> 16<br />

pressure/temperature combinations, which included temperatures <strong>of</strong> 5, 10 15 and 20 o<br />

C and 1, 50, 100 150 and 200 atm. At least 50 developing larvae from each culture<br />

were examined after 24 h and the stage attained noted (Fig. 3.7).<br />

55

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!