Structural and Biochemical Changes in Salicylic-Acid-Treated Date Palm Roots Challenged with Fusarium oxysporum f. sp. albedinis
Figure 6
Transmission electron micrographs of date palm root tissues treated with SA and infected by Fusarium oxysporum f. sp. albedinis (Foa). (a: ×5000) Preserved cell wall (Cw) in control roots (UU); (b: ×20000), (c: ×6000), (d: ×5000) Untreated inoculated roots (UI); note the marked cell wall degradation (c) as well as the alteration of the cytoplasm, which was reduced to vesicular remnants (d). (e: ×6000), (f: ×12000), (g: ×12000), (h: ×30000) SA-treated and infected plants; note the accumulation of the electron-dense material (ED) (f), which forms a coat (Co) in the vessel lumen (g) and osmiophilic droplets (OD) at sites of intercellular spaces of parenchyma cells (e). Note also the wall appositions (WA) (g) and the disruption of the Foa hypha near the electron-dense material (ED) (h). Cw: cell walls; Ve: vesicles; Co: coat; Cwd: cell wall degradation; Pl: plasmalemma; Pls: plasmodesmata; N: nuclei; Foa: Fusarium oxysporum f. sp. albedinis.
