Phytophthora cinnamomi germinating on a Port Orford Cedar leaf


Leaf of Chamaecyparis lawsoniana, Port Orford cedar, baited with Phytophthora cinnamomi, causal agent of 'phytophthora dieback', showing a clump of agar, emerging hyphae, and scattered bacteria. Leaf was sourced from HSU campus, and P. cinnamomi was sourced from Chris Lee's personal culture collection, and incubated together in soil suspension for one week. Leaves were fixed in 1.5% glutaraldehyde in 50 µM cacodylate buffer and osmium tetraoxide, dehydrated in serial dilutions of 100% ethanol, and critical-point dried. Sputter coated in gold about 320 atoms thick. Imaged using Quanta 250 scanning electron microscope, working distance 13.9 mm, backscatter electron detector, 30 kV accelerating voltage, spot size 3.0, 300X magnification.

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