090518-Effects of Temperature on Germination of Peronospora parasitica Conidia and

[이지연]

J. Phytopatbology 146, 137-141 (1998)

Effects of Temperature on Germination of Peronospora parasitica Conidia and
Infection of Brassica oleracea
p. N. ACHAR
Author's address: Department of Microbiology. University of Durban Westville, X54001. Durban 4000. South Africa

Abstract
The effect of temperature on germination of a South African isolate of Peronospora parasitica, and infection
of Brassica oleracea was studied. The optimum condition for germination was 2O'C at 100% relative humidity. The
percentage germination obtained was 80-98% and 70- 80% between 15 and 25 C at 100% relative humidity,
after a 12 and 6h incubation period, respectively. Optimum temperature for germ tube growth was also 20 C.
The temperature range for maximum infection of seedlings of a highly susceptible cabbage cultivar and subsequent
disease development in vitro was 15-25 C and 90-100% infection was achieved after 48 h of incubation.
At < 15 C and 26-30 C infection percentage was decreased to 40-50% and 35-40%, respectively. No disease
incidence was recorded at temperatures above 35 C. A scanning electron microscope study of the infection
process showed that penetration of cotyledons by germ tubes was mostly via stomata and occasionally directly
throtigh the cuticle. Results are discussed in relation to the need for future studies of P. parasitica in South
Africa.

South African isolate of Peronospora parasitica와 Brassica oleracea 간염의 발아 온도 효과를 연구했다. 발아 20도 최적온도는 100% 상대습도이었다. 발아률은 100%상대습도에 80-98%, 70- 80%와 15, 25 도 사이에서 획득했다.또한 germ tube 생장의 최적온도는 20도 였다. 이병성이 높은 배추 품종과 15-25도, 90-100% 기내안에서 충분히 병 발달된 육묘의 최고 감염 온도 범위는 48시간 incubation 후에 획득했다. 15도 26-30도 감염율은 각각 40-50%와 35-40%에서 감소 되었다. 35도 이상 온도는 병 발병률이 기록되지않았다. 주사전자 현미경 감염 과정의 주사전자현미경 연구는 세균관에 의하여 cotyledon의 침투가 stomata를 통해 그리고 때때로 직접적으로 circle을 통해서 주로 이었다는 것을 보여주었다. 결과는 남아프리카에서 P. parasitica의 미래 학문을 위한 필요에 관하여 토론된다.