Zinc regulation in Blackbeans (Phaseolus vulgaris (L.))

Abstract

Blackbeans (Phaseolus vulgaris (L.) var ‘Black Turtle') were grown on a Lakeland soil in a factorial growth chamber experiment with 0 and 8 ppm added Zn; 0, 20, 40, 80, and 160 ppm added P; and under two temperature regimes ‐ a 28°C/23°C (day/night) temperature and a 20°C/15°C (day/night) temperature. Blackbeans were also grown at two field sites in Southern Manitoba which were selected for their low supply of available zinc. Zinc, at 0 and 15 kg/ha, and phosphorus, at 0, 100, 200, 400, and 800 kg P₂0₅/ha vere disced into the soil in a factorial experiment.

Blackbean zinc uptake was much greater at the higher temperature, while phosphorus uptake was not similarly affected by temperature. Blackbean phosphorus uptake was regulated by the plant when sufficient Zn was present but was not regulated at low plant Zn levels. At low blackbean Zn levels, plant uptake of phosphorus further decreased blackbean Zn uptake. Blackbean Zn uptake was not affected by phosphorus concentration as long as Zn levels remained sufficiently high.