Figure 6.

Effects of the duration of NO₃⁻, NO₃⁻ plus NH₄⁺, and NO₂⁻ pretreatment on HvNRT2 transcript abundance. Lane 1, Plants grown in nitrogen-free medium; lanes 2 through 4, 10 mm NO₃⁻-supplied plants; lanes 5 through 7, 10 mm NH₄⁺ and 10 mm NO₃⁻-co-supplied plants; and lanes 8 through 10, 10 mm NO₂⁻-supplied plants for times shown. Twenty micrograms of total RNA was introduced into each lane and probed with HvNRT2.3 internal fragment and washed at medium stringency. Northern blot was probed with the 25S ribosomal subunit to ensure equal loading of RNA.