Abnormal Stomatal Opening in Coconut Palms Affected with Root (Wilt) Disease

Abstract

Studies on the stomatal regulation in the root (wilt) affected coconut palms (Cocos nucifera L.) revealed that the diseased palms had low stomatal resistance compared to the healthy palms, irrespective of their age. The same trend was observed whether the determinations were made at different times of the day (6–18 h) or under irrigated and unirrigated conditions or in different seasons (‘dry’ and ‘wet’). Thus, the stomatal regulation was significantly impaired in the diseased palms resulting in excessive water loss compared to the healthy palms. Results are discussed with the available literature on other similar disease caused by fungi, bacteria and mycoplasma-like organisms in different plants.