Effects of Metal Chelators on Leaf Senescence in Maize and Hydrangea

摘要

The senescence of maize and hydrangea leaves after being detached and kept in the dark was studied in terms of the loss of chlorophyll. Chlorophyll was more rapidly degraded in maize than hydrangea during the incubation period in the dark. The loss of chlorophyll in the dark was effectively inhibited in both plants byα,α′-dipyridyl ando-phenanthroline at concentrations between 0.01 and 0.1 mM. Three other chelators of iron produced lesser inhibition and only at higher concentrations. EDTA prevented the loss of chlorophyll in maize leaves at concentrations above 10 mM, but did not do so in hydrangea leaves.Detached leaves floated on EDTA,α,α′-dipyridyl oro-phenanthroline solutions and exposed to light exhibited a marked bleaching. The bleaching was partially inhibited by applying ascorb