Figure 8.

Regulation of APR by salt in mutants deficient in hormone signaling. Arabidopsis mutants or transgenic lines deficient in cytokinin perception (ahk4), cytokinin accumulation (CKX), auxin signaling (axr1), and tir1 or GA-signaling gai plus the corresponding wild types (Col-0 or Ler) were grown in hydroculture and treated with 150 mm NaCl for 5 h. The relative mRNA levels for APR1 (A), APR2 (B), APR3 (C), and RD29A (D) in roots were determined by semiquantitative RT-PCR and standardized with actin 2/7 transcript. E, APR activity was measured in crude root extracts. Data are presented as means ± sds of three independent plants. All treatments were repeated at least twice with similar results. Different indices indicate values significantly different at P ≤ 0.05. Values marked with asterisks are significantly (P ≤ 0.05) different from nontreated plants.