Content of Metals in Leaves of Ulmus campestris L. Influenced by Tetraneura ulmi de Geer (Aphidoodea, Eriosomatidae)

1988

S. 179-191

14 Abb., 9 Lit. Ang.

Unselbständiges Werk

200031008

Results based on comparison of concentrations of measuredmetals in leaf tissues of Ulmus campestris L. and in the gall biomass, which d evelop on blades due to sucking activities of fundatrix and virginogenic of thespecies Tetraneura ulmi, are similar to results obtained with comparison of me tal content in willow leaves and their gall which parasitize on them due to 2 species of the genus Pontania, as well as in the biomass of poplar leaves and their gall tissues which develop on leaf-stalks due to sucking activities of Pemphigus spirothecae. Metals are classified in 3 groups: a) The 1st group shows a lower ion concentration in gall tissues and a higher concentration in the leaf biomass (Mg, Fe, Ca, Al, Mn, Sr and Cd). b) The 2nd group of metals tends to a somewhat lower ion concentration in gall biomass contrary to blades (Na, Ni, Pb, Zn). c) The 3rd group shows a similar content both in gall and leaf tissues of host woody plants or tends to a higher level in galls than in leaves (K, Cr, Cu). Changed concentrations in galls contrary to their content in leaves may be regarded as a result of biological processes influenced due to so far not fully known biophysical, biochemical, general physiological mechanisms. The point is in fact, that leaf tissues are used for a development of galls with trophic favourable tissues, or better, with trophic suitable concentrations of measured elements. The same is true for this case, i.e. if metal concentrations in galls and leaves are approximatively the same, the matter will be with a high probability an equilization of concentration levels due to biological processes, with results concerning photosynthesis in leaf tissues on one hand, and growth of gall tissues on the other hand, being influenced and regulated by aphides' sucking. A level of biologically very important metals may increase, with regardto demands of aphides in galls contrary to leaves; a level of toxic metals in galls contrary to leaves may decrease. A content of highly concentrated bioelements in leaves may be decreased in galls, while demands of insects which use galls for their development are substantially lower.