The influence of different forms and concentrations of nitrogen on total nonstructural carbohydrate allocation and growth in Digitaria eriantha.

Abstract

Digitaria eriantha plants were grown under controlled conditions for a period of three months, during which time they were supplied with the following forms and concentrations of nitrogen: 50 mg/l NO3 - -N, 200 mg/l NO3 -N, 200mg/l NH4 +-N and a combined form containing both NO3 - -N and NH4 + -N with a nitrogen concentration of 200 mg/l. Control plants received no nitrogen. At monthly intervals both above and below ground components were assayed for soluble and insoluble carbohydrate contents. Dry mass and leaf areas were also measured. The nitrogen treatments were found to influence the allocation of photosynthates into either soluble or insoluble carbohydrates. In above ground tissue, the soluble carbohydrate component decreased with time, while the insoluble component increased with time. In root tissue the reverse trends were observed. Both dry mass and leaf area development were enhanced in plants supplied with nitrogen in any form. It was suggested that growth of D. eriantha was influenced by carbohydrate fluctuations.D. eriantha

Keywords: botany; carbohydrates; digitaria eriantha; dry mass; growth; leaf area; leaves; nitrogen; physiology; plant physiology; south africa