Zum Ionenhaushalt einiger Plantago-Arten

Abstract

Summary Shoot samples of P. maritima L., P. major L. ssp. major , P. lanceolata L., and P. media L. were collected from different natural habitats and analysed for their content of following compounds: K, Na, Ca, Mg; Cl, SO 4 , NO 3 , PO 4 ; organic acids and total anions. The results revealed „physiotypical‟ peculiarities as well as ecological aspects. Regarding the pattern of mineral cations the halophyte P. maritima strongly accumulates Na and Mg on saline soils east of the „Neusiedler-see‟ Lake in Austria. On calcareous habitats enhanced levels of soluble Ca are stored in addition to K by all species under investigation. Concerning the content of inorganic anions, the non-halophytic members P. major ssp. major and P. lanceolata tend to store Cl and SO 4 to a larger extent than do glycophytic species of other families. In P. media the accumulation of inorganic anions is generally less markedly pronounced. The Cl/SO 4 -ratio in the cell sap of P. maritima largely depends on the salt content of the substrate: on salt-rich habitats high intake of SO 4 is remarkable, whereas on soils low in salt Cl is prefered. Striking differences could be detected in the qualitative pattern of organic acid components: P. media produces high levels of malonate which contribute to charge balance in the shoot; in P. major ssp. major isocitrate is the dominant organic anion; P. lanceolata stores malate, citrate, and fumarate; P. maritima contains mainly malate. At least two physiological features of the Plantago species investigated may be of ecological significance: the ability to accumulate high concentrations of soluble Ca as osmotically active ion within the vacuole might enable the plants to cope with xerothermic limestone soils; on the other hand, the general physiological disposition to store larger amounts of Cl and SO 4 might assist the adaptation to saline environments.