Nitric-oxide inhibits nyctinastic closure through cGMP in Albizia lophantha leaflets

Rhythms in Plants

“…The involvement of nitrous oxide (NO-the gaseous signalling molecule with well-established physiology in animals) in nyctinastic leaf closure (closure upon the regular light-to-dark transition) was explored in the classic system of leaflets with tertiary pulvini of Albizzia lophanta floating on various experimental solution combined with systematic pharmacological treatment based on the animal system paradigm (Bergareche et al 2014). NO levels were manipulated by applying, in the experimental solutions, NO donors, NO scavengers and an inhibitor of NO synthase, and an inhibitor of a plant-specific pathway of NO production via nitrate reductase (ibid.).…”

“…In Albizzia lophanta leaflets, Ca 2+ also enhanced leaflet closure, i.e. enhanced extensor shrinking, which suggests that Ca 2+ does not participate in NO inhibition of leaflet closure (Bergareche et al 2014). Could NO inhibit leaflet closure by a two-prong effect: causing swelling of the extensor via cGMP without Ca 2+ and causing flexor shrinking (concomitant with extensor swelling) via 8-nitro-cGMP and elevation of cytosolic Ca 2+ levels in flexors?…”