| Abstract: | Farnesol accumulates in water-stressed plants of Sorghum, andhas been shown to induce closure of stomata in the Commelinabioassay. In the present study we have found that it inhibitsbicarbonate- and PGA-stimulated O2 evolution of isolated Pisumchloroplasts. Farnesol apparently disrupts the membranes ofisolated plastids and most of the effects that we have observedcan probably be attributed to this. Apart from nerolidol, relatedisoprenoid alcohols had no comparable effects, but the fattyacid linoleic acid appeared to cause damage of a similar nature.These compounds all caused stomata of Commelina to close. It is suggested that, while farnesol causes irreversible damageto membranes when applied exogenously in in vitro systems, itmight act in vivo as a regulator of membrane structure and soaffect the solute movements on which the turgor changes of guardcells depend. |
