Ammonium and Nitrate Accumulation in Containerized Southern Highbush Blueberry Plants

Abstract

Ammonium and uptake and partitioning were monitored in `Sharpblue' southern highbush blueberry plants ( Vaccinium corymbosum L. interspecific hybrid) using 10% 15 N-enriched N. Shoots and roots were harvested at 0, 6, 12, 24, and 48 hours after labeling. The rate of -N uptake was higher than that of -N uptake, averaging 17.1 vs. 8.6 g N/g plant dry weight per hour during the 48-hour period for -N and -N plants, respectively. At the end of the 48 hours, -N accumulation averaged 79 mg N/plant compared to 40 mg accumulated by the -N plants. Similarly, the translocation rate of -N to shoots was higher than translocation of -N to shoots (7.7 vs. 1.9 g N/g shoot dry weight per hour, respectively) during the 48 hours. Shoot accumulation of -N averaged 40 mg N/plant at the end of 48 hours, while accumulation in shoots of -N plants averaged 10 mg N/plant. Short-term uptake and translocation to shoots appears to be limited relative to uptake and translocation in southern highbush blueberry when plants are previously fertilized with NH 4 NO 3 .