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> COLORATUM , Vaartaja, Mycologia 57:417 (1965). Figs 24-26<br />
COLONY MORPHOJ..,OGY: Colonies on CMA forming an indistinct<br />
chrysanthemum growth pattern; no development of aerial mycelium.<br />
MYCELIUM: Main hyphe 3-6 (av. 4) um wide. SPORANGIA:Filamerrtous,<br />
terminal Or intercalary, slightly inflated. Zoospores formed at room<br />
temperature, vesicles up to 55 urn diam. OOGONIA: Terminal, or occasionally<br />
intercalary, globose Or pyriform, smooth sometimes with papilla, 17-23 (av. 19.7<br />
± 0.8-95% C-I) urn diam. AN<strong>THE</strong>RIDIA: Diclinous and monoclinous, 1-<br />
4/ oogonium, clavate, crooknecked, antheridial stalk sometimes branching into<br />
two branches with a septum at the branching point, one antheridial cell is borne<br />
at each branch. OOSPORES: Aplerotic, 12-19 (av. 16.2 ± 0.7-95% C.I) .urn<br />
diam, wall 1-2 (av. 1.7 ± 0.2-95% C.l.).um thick. Ooplast 6-11 (av. 7.7)um diam.<br />
TEMPERATURE-GROWTH RELATIONSHIPS: Minimum 5 0C, optimum<br />
250C, maximum 300C. Daily growth rate on CMA at 25 0C 13.8mm.<br />
MA TERIAL EXAMINED: ex Raphanus sativus L., Ram AlIa' (FCCAU<br />
/03.6); ex Lens culinaris Medik, Nablus (FCCAU 103·7); ex soil, Bethlehem<br />
(FCCAU 103.1), and several other isolates.<br />
OCCURRENCE: Infrequntly isolated from diseased roots and stream water,<br />
and rarely from soil (found in 15% of the soils sampled).<br />
<strong>PYTHIUM</strong> CONIDIOPHORUM Jokl, OSlo bot. Z. 67:33-36 (1918) Figs 27-<br />
29<br />
COLONY MORPHOLOGY: Colonies on CMA forming a diffuse pattern; no<br />
development of aerial mycelium. MYCELIUM: Main hyphae 3-6.um wide, no<br />
catenulate appressoria ever observed. SPORANGIA and zoospores not formed.<br />
HYPHAL SWELLINGS: Terminal and intercalary, globose, dark, granulated,<br />
usually germinating by several germ tubes, 16-30 (av, 21.8±0.8-95% Cd.uim<br />
diam. OOGONIA: Mostly terminal, occasionally intercalary, smooth, 7-16 (av.<br />
13.1 ± 0.5-95% C.l.),um diam. AN<strong>THE</strong>RIDIA: Absent. OOSPORES: Plerotic,<br />
wall 1-2.5 (av. 1.8± 0.2-95% C.l.),um thick. TEMPERATURE-GROWTH<br />
RELATIONSHIPS:Minimum 0-5 0 C, optimum 200 C, maximum 30-35 C. Daily<br />
growth rate on CMA at 25 0 C 12mm.<br />
MATERIAL EXAMINAD: ex soil, Bethlehem (FCCAU 115.1);and ex<br />
stream bed, Nablus (FCCAU 115.2; FCCAU 115.3).<br />
OCCURRENCE: Rarely isolated from soil (found in 2% of the fields sampled<br />
and stream bed.<br />
24
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