Figure 7.

Respiratory burst oxidase homolog D (AtRBOHD) mediates melatonin-induced accumulation of cytoplasmic free Ca²⁺ ([Ca²⁺]_cyt) in Arabidopsis response to cold stress. (A) Fluorescence images. (B) Fluorescence intensity. The protoplasts from leaves of wild-type (WT) Arabidopsis or Atrbohd mutant were incubated with Fluo-4 acetoxymethyl (AM) ester at 37 °C in the dark. After 30 min, the protoplasts were treated with melatonin (10 µM) and then placed at 4 °C for 5 min (cold stress, CS). Data in (B) are expressed as means ± standard deviation (SD, n ≥ 7). The different letters mean significant difference at p < 0.05 according to Turkey’s test. CK, control.