Authors: Anders Kjær Francel Verstappen Harro Bouwmeester Elise Ivarsen Xavier Fretté Lars P Christensen Kai Grevsen Martin Jensen
Publish Date: 2012/11/24
Volume: 237, Issue: 4, Pages: 955-966
Abstract
The concentration of the lifesaving antimalarial compound artemisinin AN in cultivated Artemisia annua A annua plants is relatively low and thus research in improving the content is important In the present study external stress was applied to adult plants of A annua and the effect was examined on the concentrations of AN and its immediate precursors in leaves and these concentrations were related to densities and sizes of the glandular trichomes GT Plants were stress treated weekly five times by sandblasting or spraying with salicylic acid chitosan oligosaccharide H2O2 and NaCl solutions Contents of ANrelated compounds ANc were analysed in leaf samples from an upper and a lower position of the plants and GT were quantified and measured In lower leaves several stress treatments had significant negative effects on concentrations of ANc whereas the ratios between compounds showed an increased conversion to AN In the upper leaves no changes were observed compared to controls Linear relations were found between the concentrations of metabolites and the density of GT in both upper and lower leaves and size of GT in lower leaves Results suggested that older and younger leaves may respond differently to applied stress A part of the plants were infected by powdery mildew and this caused significantly different compositions of the ANc compared to uninfected plants In conclusion changes in concentrations of ANc seemed largely to be related to changes in GT densities and sizes
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