Canadian Forest Service Publications

Low light intensity predisposes black spruce seedlings to infection by Botrytis cinerea. 1995. Zhang, P.G.; Sutton, J.C.; He, B.; Hopkin, A.A. Canadian Journal of Plant Pathology 17:13-18.

Year: 1995

Issued by: Great Lakes Forestry Centre

Catalog ID: 34462

Language: English

Availability: PDF (request by e-mail)

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Abstract

Seedlings of black spruce [Picea mariana] were kept in low light intensities for 0-42 days and inoculated with Botrytis cinerea (106conidia/mL). Infection was assessed indirectly by estimating sporulation incidence of the pathogen on 6-mm segments of theneedles. Sporulation incidence in seedlings kept in light (400-700 nm) intensity of 0 and 7 umol-nr2-s"1 was 0.7% and 0.4% after 6 and 12 days of the preinoculation treatment, increased to maximum levels of 45.6% and 32.5%, after 21 and 27 days, and declined after 27 and 39 days, respectively. Sporulation incidence was zero in seedlings kept at 15 and 30 umol-nv2^"1 for up to 24 and 39 days before inoculation, and <6.3% and <0.4% after 30 and 42 days, respectively. Botrytis cinerea sporulated on needles only when light intensity was sufficiently low that the chlorophyll content fell below 1.3-1.4 ug/6-mm segment. In studies in canopies of seedlings in greenhouses, sporulation incidence decreased as light intensity increased and reached zero when the mean intensity at noon on sunny days was near 10 umolm~2s"'.We conclude that light (400-700 nm wavelength) intensity of <10 umolm^s"1 predisposed the needles to infection by B. cinerea.