Inhibition of photosynthesis in Melia azedarach and Ligustrum lucidum induced by manganese toxicity using OJIP chlorophyll a fluorescence transient

Using Chlorophyll Fluorescence to Study Photosynthesis*

Each quantum of light absorbed by a chlorophyll molecule rises an electron from the ground state to an excited state. Upon de-excitation from a chlorophyll a molecule from excited state 1 to ground state, a small proportion (3-5% in vivo) of the excitation energy is dissipated as red fluorescence. The indicator function of chlorophyll fluorescence arises from the fact that fluorescence emission...

Potent limonoid insect antifeedant from Melia azedarach.

Systematic fractionation of a fruit extract from Argentine Melia azedarach L., which was monitored by an insect antifeedant bioassay, led to the isolation of meliartenin, a limonoid antifeedant, which existed as a mixture of two interchangeable isomers. At 4 microg/cm2 and 1 microg/cm2, the isomeric mixture was as active as azadirachtin in strongly inhibiting the larval feeding of Epilachna pae...

Early stage toxicity of excess copper to photosystem II of Chlorella pyrenoidosa-OJIP chlorophyll a fluorescence analysis.

Acute toxicity of excess Cu on the photosynthetic performance of Chlorella pyrenoidosa was examined by using chlorophyll a fluorescence transients and JIP-test after exposure to elevated Cu concentrations for a short time period. High Cu concentration resulted in a significant suppression in photosynthesis and respiration. The absorption flux (ABS/RC) per PSII reaction center increased with inc...

Fatty Acid Composition and Toxicity of Melia azedarach L. Fruits against Malaria Vector Anopheles stephensi

      The fruit of Melia azedarach L. (Meliaceae) was extracted with hexane, and its fatty acids methyl ester was analyzed using GC/MS. Thirteen components representing 85.1% of the total extract were identified. The major components identified were methyl palmitate (18.8%), methyl linolenate (16.1%) and methyl linoleate (9.8%). The fruits’ extract had a LC50 of 5.5 ppm agai...

Anti-moulting activity in Brazilian Melia azedarach.