The epidermis of barley leaves is a dynamic intermediary storage compartment of carbohydrates, amino acids and nitrate
- 1 September 1994
- journal article
- Published by Wiley in Physiologia Plantarum
- Vol. 92 (1) , 31-36
- https://doi.org/10.1111/j.1399-3054.1994.tb06651.x
Abstract
Sugars, amino acids and nitrate were measured in the epidermis of barley seedlings and compared with whole leaf levels. I. Under all conditions, concentrations of glucose and fructose were lower in the epidermis than in the remaining leaf tissues; levels were lowest at the end of the dark period (0.2–1.4 mM) and increased under conditions of inhibited assimilate export (3–6 mM). 2. Epidermal sucrose concentrations were very low (« 0.2 mM) even in excised leaves which had accumulated assimilates. 3. Similar to the sugars, amino acids were also less concentrated in the epidermis than in whole leaf extracts. However, the amino acid profiles showed cell type‐specific differences. 4. Nitrate was accumulated in the epidermis. The epidermal pool decreased during nitrate starvation. Since no nitrate reductase activity was associated with the epidermis, nitrate was mobilised from the epidermis and metabolized presumably in the mesophyll. These results suggest that the epidermis functions as a regulated intermediary storage compartment of the leaves and that stored substances are readily available for remobilisation.Keywords
This publication has 19 references indexed in Scilit:
- Compartmentation and transport of zinc in barley primary leaves as basic mechanisms involved in zinc tolerancePlant, Cell & Environment, 1994
- Intercellular Compartmentation of Ions in Barley Leaves in Relation to Potassium Nutrition and SalinityJournal of Experimental Botany, 1993
- The uptake of glucose, fructose and sucrose into the lower epidermis of leaf discs of pea (Pisum sativum L. cv. Argenteum)New Phytologist, 1993
- Purification and compartmentation of α-mannosidase isoenzymes of barley leavesPhytochemistry, 1992
- Amino Acid and Sucrose Content Determined in the Cytosolic, Chloroplastic, and Vacuolar Compartments and in the Phloem Sap of Spinach LeavesPlant Physiology, 1991
- Fructan Metabolism in Grasses and CerealsAnnual Review of Plant Biology, 1991
- Fructan Metabolism In Grasses And CerealsAnnual Review of Plant Biology, 1991
- Amino Acid Transport across the Tonoplast of Vacuoles Isolated from Barley Mesophyll ProtoplastsPlant Physiology, 1990
- Low CO2 Prevents Nitrate Reduction in LeavesPlant Physiology, 1989
- Measurement of Subcellular Metabolite Levels in Leaves by Fractionation of Freeze-Stopped Material in Nonaqueous MediaPlant Physiology, 1984