Influence of hydrogen fluoride fumigation on the water economy of soybean plants.

The influence of hydrogen fluoride fumigation on water economy was studied using soybean (Glycine max [L] Merr.). Fumigation caused partial stomatal closure in 1 hour and practically complete closure within 4 hours. The transpiration rate was greatly reduced by fumigation, while the leaf temperature was increased. Water potential increased after 1 day but fell drastically when necrosis occurred. Effects of interrupted fumigation during the day were somewhat less severe in all respects than those of continuous fumigation; nighttime fumigation caused only minor effects. Fluoride uptake was also much less from nighttime than from daytime fumigations.