Modifications of Root Geometry in Winter Wheat by Phosphorus Deprivation

Abstract

Summary The effects of phosphorus (P) deprivation on root geometry in winter wheat ( Triticum aestivum ) were studied. In the first week the plants were grown in complete nutrient solutions at 2P levels (10 μM and 1000 μM phosphate), and in the second week both concentrations of P were omitted in the nutrient solution for half of the plants. The plants were harvested on days 7,9, 11,13 and 14, dried and analysed for P. Lateral and seminal root length and number were determined. The low P plants had lower dry weights and lower P contents in the dry matter than the high P plants. P was retranslocated from shoot to root in the P deprived plants. In the deprived high P plants, a high P level in the root could be sustained until day 11, whereafter it decreased to about the same level as in the root of the low P plants. P affected mainly the number of laterals. After two weeks most of the parameters (lateral root number and length, dry weight, P content) determined for the different categories of plants could be ranked in the order: deprived low P