Figure 2.

Time course of gravistimulated Ivr2 transcript accumulation in maize stem pulvini. Maize plants were gravistimulated for the time indicated and were harvested into upper and lower halves. Total RNA was isolated and hybridized with an Ivr2 cDNA probe, radioactivity stripped, and the membrane was rehybridized with an 18S rRNA probe. Ivr2 and 18S hybridization signals were quantified using a densitometer, and Ivr2 expression levels in each treatment were normalized to the 18S loading control. Transcript accumulation in gravistimulated samples is expressed relative to the vertical control (set to 1). The experiment was repeated at least three times and a representative result is shown with the corresponding northern (inset).