Phosphorus in plant physiology P content of plants Approximately 0.2% of plant dry weight is P Plants require a relatively large amount of P. The phosphate concentration in the cytosol is maintained at fairly constant concentrations in the 5 to 8 mol/m3 regardless of the external phosphate concentration except under severe P deficiency. By contrast is the vacuolar phosphate concentration
THE CELL WALL Before traversing the plasma membrane(p. m., ions must first cross the cell wall and contact the p. m the bulk flow of soil solution coul theoretically carry inorganic ions into the cell wall and through the apoplastic pathway. The thickness of a cell wall is in the range of 500 to 1000 nm. It is porous
Scope of this lecture Root functions: for plant, soil and ecosystem Root structure and pathways for uptake of nutrients the symplast and apoplast Root architecture(结构) and morphology(形态) Responses of roots and root systems to environmental stress Root hairs and their functions Introduction to combined strategies for efficient
Acknowledge I expresses thanks to Assoc. Prof. rob Reid of Adelaide university of Australia, Dr Jeff Gale, foreign teacher of northwest A&F University of China, and Prof. Zhang Fusuo, Prof. Li Xiaolin of China Agriculture University, Prof Liu Yuanyin of Northeast agriculture Unversity and other authors who provide materials for me, or whose materials, such as photographs and figures etc, I used in the lectures
Concept of organic fertilizers Organic fertilizers-that are derived from the wastes and residues of plants or animals. Such as manure, sewage sludge etc. Some consist of unprocessed plant materials(such as tree leaves, grass clipping, crop residues, and green manure crops)
Plant K A. Potassium content of plants 1.20-50gkg-1 2. Plants take up large amount of K. Only N is taken up more. 3. In some plants (sugar beets and potatoes) K uptake is greater than N uptake
Calcium in physiology Uptake and translocation Higher plants often contain apprecia ble amounts Ca and generally in the order of about 5-30 mg Ca/g dry matter The high Ca2+ concentrations related with the high Ca2+ levels in media not related with the Ca2+ uptake
