Über die Salzsekretion hei Halimione portulacoides (L.) Aellen

Summary Salt secretion was studied in Halimione portulacoiaes cultured in nutrient solutions. The organ of secretion are bladders, found on both sides of the epidermis of the leaf. They are built similar to the bladders of the genus Atriplex , consisting of a small stalk cell, filled with protoplasm and a larger vacuolated final cell. At high salinity of the nutrient solution the secreted sap of the bladders always contains a higher concentration of ions than the sap (pressed sap) of the mesophyll cells. The content of ions both of the pressed sap of the leaf tissue and the secreted sap of the bladder cells is influenced by the concentration of salt of the nutrient solution. High concentrations of NaCl promote the accumulation and secretion of Na + - and Cl — -ions and high concentrations of KCl those of K + - and Cl — -ions. Between the Na + - and K + -ions antagonistic relations are to be found. The greatest differences in the concentration of the pressed sap and that of the secreted sap are to be observed at the Na + - and HCO 3 — -ions. Analysis of the procentual composition of the secreted sap showed, that among the cations Na + - and K + -ions and among the anions HCO 3 — - and Cl — -ions are dominant. Apart from these ions only Mg ++ -ions seem to be secreted against a concentration gradient. Ca ++ -, NO 3 — -, SO 4 —— - and HPO 4 —— -ions in the secreted sap are always to be found with smaller procentual shares than in the pressed sap of the leaf tissue. Anantomic analysis of the leaves showed numerous cristals of oxalate. Furthermore the chemical analysis also showed a high oxalat content of the leaf tissue, which is increased by a high concentration of NaCl of the nutrient solution, enhancing, however, the watersoluble oxalate only. High concentrations of CaCl 2 in the nutrient solution effects the total oxalate to be waterinsoluble.