Upward movement of minerals from roots mostly occurs through xylem alongwith the

Upward movement of minerals from roots mostly occurs through xylem alongwith the ascent of sap. It is confirmed (1) Ringing experiment, involving removal of phloem containing bark, does not disturb mineral uptake till the roots in active. (ii) Tracer technique (Stout and Hoagland, 1938) using radio-active mineral shows that the mineral passes upward exclusively through xylem if the bark is separated from it by paraffin paper. Export of minerals from leaf occurs throug phloem. Phloem can pass mineral both in upward and downward directions.