Effect of inhibitors on synthesis of fatty acyl chains present in waxes on developing maize leaves

Abstract

Free fatty acids were identified as the fifth lipid class in wax from green leaf segments. They were not isolatable from the wax on yellow leaf segments, which also lacked aldehydes and appeared to have more esters and alkanes than primary alcohols. The chain length spectra of the alkanes and both ester moieties from yellow tissue are distinguishable from those of green tissue by the prominent amounts of shorter homologues, but the homologue distributions of the aldehydes and primary alcohols from the two types of tissue were similar. Tissue slices from yellow leaf segments incorporated 8.7% of the14C into wax lipids, whereas those from green segments were only half as efficient. In all wax fractions shorter homologues contained relatively more14C if they came from wax synthesized by yellow rather than green tissue. In wax from green tissue slices, 75% of the14C was in 32 carbon chains compared to 29% in that from yellow tissue slices. Pre-treatment of green tissue slices with 2.5 umol of Cl3AcONa inhibited total wax synthesis by 49%, primarily via blocking synthesis of C32 chains. While pre-treatment of yellow tissue slices with 2.5 μmol of triallate inhibited total wax synthesis by only 10%, C32 chain synthesis was reduced by 2,600 pmol (41%). In contrast to the Cl3AcONa inhibition, this reduction was to a large extent (1,700 pmol) compensated for by increases in C28 and C30 chain synthesis.