Fig. 2From: Overexpression of MfPIP2-7 from Medicago falcata promotes cold tolerance and growth under NO3 − deficiency in transgenic tobacco plantsAnalysis of transgenic tobacco plants (lines 3-1, 4-2 and 7-2) overexpressing MfPIP2-7 in comparison to the wild-type control (WT). Fifteen μg of DNA from each plant line were digested with HindIII for DNA hybridization (a). Relative expression of MfPIP2-7 was determined by qRT-PCR (b). Survival rate was determined at 3 d post recovery at room temperature after plants were treated by freezing at −3 °C for 6 h (c). Photographs were taken before freezing (upper) and 3 d post recovery at room temperature after freezing treatment (lower, d). Ion leakage was measured to calculate the temperature that resulted in 50 % lethal (TL50, e). Means of three independent samples and standard errors are presented; the same letter above the column indicates no significant difference at P < 0.05Back to article page