THE GENUS PYTHIUM - An-Najah National University
THE GENUS PYTHIUM - An-Najah National University
THE GENUS PYTHIUM - An-Najah National University
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<strong>PYTHIUM</strong> ECHINULATUM Matthews, Studies on the Genus Pythium,<br />
(Univ. of Carolina Press) p. 101 (1931). Figs 48-54<br />
COLONY MORPHOLOGY:Colonies on CMA forming a rosette growth<br />
pattern; no development of aerial mycelium. MYCELIUM:Main hyphae 3-7 (av.<br />
4.4),um wide. SPORANGIA: Subglobose to elongate, terminal or intercalary,<br />
sometimes 3 to 5 in a chain, (13-40)x( l3-33) avo 27x24..um diam. Zoospores<br />
produced at 5-20° C. OOGONIA: Terminal or intercalary, subglobose, 17-23 (av<br />
20.9± 0.5-95% c.i.) .urn diam, provided with conical pointed spines 8-14<br />
(av.11.0) AIm long. AN<strong>THE</strong>RIDIA: Typically hypogynous, 1-2/ oogonium.<br />
rarely monoclinous sessile. OOSPORES:Aplerotic (oospore vol. I oogonium vol.-<br />
0.69),single, sometimes 2/00gonium, 15-21 (av. 18.5± 0.4-95% C. I.),.um diam,<br />
wall 1-1.5 (av. 1.2± 0.1-95 % C.I.)llm thick. Ooplast 7-11 (av. 9.6)..um diam.<br />
TEMPERATURE-GROWTH RELATIONSHIPS:Minimum 5°C, optimum 20-<br />
30 0 C, maximum 35 0 C. Daily growth rate on CMA at 25 0C 8.4mm.<br />
MATERIAL EXAMINED: ex soil, Nablus (FCCAU 127.1), Jenin(FCCAU<br />
127.2), and Ram Alia" (FCCAU 127.3).<br />
OCCURRENCE:Seldom present in irrigated fields (found in 23% of these<br />
soils); it was absent in nonirrigated fields.<br />
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