Figure 6. ABA accumulates after wounding under dry conditions and affects resistance to B. cinerea.

Leaves were wounded and maintained for 1.5 h under high humidity in tightly covered well-watered trays (humid) or in uncovered trays at room conditions (dry) prior to measurement of ABA or luciferase activity. (A) Measurement of ABA in ng mg⁻¹ fresh weight of plant tissue in unwounded or wounded plants, incubated under humid or dry conditions (n = 6; ±SD). Different letters above each bar represent statistically significant differences (Dunn's test; P<0.05). (B) Expression of pAtLTI23T::LUC or pAtHB6T::LUC in wounded leaves incubated either under humid or dry conditions compared to unwounded plants. The wounds inflicted by the forceps (arrows) show a stronger expression of the LUC gene in plants incubated under dry conditions. The experiment was repeated 3 times, one typical result is represented. (C) Effect of exogenous ABA treatment (leaf discs were floated on 100 mM ABA, 1 d prior to wounding). After wounding, ROS (measured as DCF-DA fluorescence) and growth of B. cinerea (Bc) (leaf discs were floated on water and inoculated; Trypan blue staining was carried out 2 d after inoculation) were determined (the experiment was carried out 3 times, one typical result is represented).