REGULATION OF NH4-N UPTAKE IN BLUEBERRY PLANTS AND CITRUS NATSUDAIDAI
The capacities to regulate NH4-N uptake were compared between blueberry plants (Vaccinium ashei Reade cv. Tifblue) and Citrus natsudaidai Hayata. Plants of both species were grown in N-free nutrient solutions for 3 days and then transferred to nutrient solutions at various concentrations of NH4-N. Blueberry plants showed the increase in NH4-N uptake rate 8 to 24 h after NH4-N application. At NH4-N concentrations above 200 μM, NH4-N uptake rates decreased to the initial value 24 h after NH4-N application, and then increased. In contrast, Citrus natsudaidai seedlings showed constant NH4-N uptake rates during the experiment. These results indicated that blueberry plants were able to repress NH4-N uptake periodically when they were exposed to high external NH4-N concentrations, but were not Citrus natsudaidai.
Sugiyama, N. and Hirooka, M. (1993). REGULATION OF NH4-N UPTAKE IN BLUEBERRY PLANTS AND CITRUS NATSUDAIDAI. Acta Hortic. 345, 157-162