Influence of Humidity and Red-Infrared Radiation on Spore Discharge byDrechslera turcica-- Additional Evidence
- 1 January 1980
- journal article
- research article
- Published by Scientific Societies in Phytopathology®
- Vol. 70 (3) , 192-196
- https://doi.org/10.1094/phyto-70-192
Abstract
The influence of atmospheric humidity and red-IR radiation on release of conidia from maize [Zea mays] leaf lesions was studied in a series of experiments using a special spore release apparatus. Temperature and air velocity were kept constant in all experiments. A low air velocity (0.5 m/sec) was selected to minimize the possibility of wind removal. Irradiation of sporulating maize leaf lesions with red-IR radiation greatly increased spore release at lowered relative humidities (RH), but not when the air was saturated. Numbers of spores liberated from irradiated specimens always greatly exceeded those released in darkness under the same conditions. Even short exposures (1-2 min) of IR at constant low relative humidity caused massive release of conidia. A water filter (20 cm deep) used to remove heat had little effect on spore release. When visible wavelengths were eliminated by filters, the IR alone (> 800 nm) triggered spore release. Experiments confirmed earlier reports that spore release may be initiated by either lowering or raising the atmospheric humidity. When the humidity was lowered and raised in a cyclical manner, a characteristic bimodal pattern of spore liberation occurred. The first major peak of spore release always coincided with humidity reduction and a 2nd peak resulted from the raising of the humidity. The number of spores released by these humidity changes was higher when the changes occurred at fairly low humidities and was less near saturation. Though spore release triggered by humidity changes in darkness was less than in specimens exposed to red-IR radiation, when the humidity was repeatedly cycled (lowered and raised) in darkness, the number of spores released progressively increased for each successive cycle.Keywords
This publication has 3 references indexed in Scilit:
- An Apparatus for Precise Control of Humidity, Temperature, Air Flow, and Light in Spore Discharge StudiesPhytopathology®, 1980
- Patterns of conidial release by Helminthosporium turcicum on sweet corn under controlled environmental conditionsCanadian Journal of Botany, 1977
- An Electrostatic Theory to Explain Violent Spore Liberation by Drechslera turcica and Other FungiMycologia, 1976