Studies on sunflower rust. V. Culture ofPuccinia helianthithroughout its complete life cycle on detached leaves of sunflower (Helianthus annuus)

摘要

Detached leaves of sunflowers on various substrates in petri plates retained some green color for 36 days at day and night temperatures of 22 and 20 deg;C respectively, and for 55 days at a continuous temperature of 10 deg;C. Water agar proved best of the substrates tried. Uredia developed in 9 to 10 days after inoculation with urediospores at 22minus;20 deg;C, and in 14 to 20 days at 10 deg;C. Telia developed in 14 to 20 days after inoculation at 22minus;20 deg;C, and in 22 days at 10 deg;C. Teliospores produced at 22minus;20 deg;C could not be induced to germinate. Those produced at 10 deg;C began to germinate 15 days after formation. Several complete cycles from teliospore to teliospore were produced on detached leaves. The time required per cycle averaged about 80 days.