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Lettuce

Lactuca sativa L.

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Symptoms induced in controlled conditions (fumigation with ozone)

cv. Cogollo de Tudela

Chorotic lesions produced by ozone exposure on lettuce cv. Cogollo de Tudela lesions join together appearing like a continuous chorosis (A). Sometimes bifacial necrosis are observed in small areas of old leaves (B)

cv. Romana del Prat

Ozone symptoms on lettuce cv. Romana del Prat appears on the tip of the oldest leaves as a chlorotic stippling (B and D). It can be easily distinguished with comparing with healthy leaf (C). Ozone lesions join together and the tip of the leaf turn into chlorotic completely (A and B). Chronic exposures to ozone produces bronzing or reddish lesions (E).

cv. Iceberg El Toro

Lettuce cv. Iceberg El Toro shows slight small chlorotic stippling on the old leaves of the plant (A and B). Small necrosis spots can be observed occasionally (B).

© 2009 Fundación CEAM © 2009 Copyright of the photos: their authors