Transcript profiles of P. densata conserved miRNAs. Samples are needles and stems of 2-month-old seedlings. The expression levels of all miRNAs by real-time PCR were relative to that of 5 S rRNA and normalized. Error bars represent the standard deviations of three PCR replicates of a single reverse transcription reaction. The normalized miRNA levels in stems were arbitrarily set to 1.