Fig. 6From: Adaptation of cucumber seedlings to low temperature stress by reducing nitrate to ammonium during it’s transportationEffect of low temperature on nitrate reductase (NR) and nitrite reductase (NiR) activities of cucumber seedlings. (A) NRAmax, the maximum activity of nitrate reductase; (B) NRAact, the actual activity of nitrate reductase; (C) NiR activity, the activity of nitrite reductase. Error bars represent the standard error of the mean (n = 3). Different lower-case letters indicate a significant difference (P < 0.05)Back to article page