Figure 3.

Ultrastructural aspects of the spongy parenchyma cells of P. caerulea leaves after 60 days from the first treatment with plant biostimulants; (a1,b1,c1): C, control (no treatment with plant biostimulants, treated only with water); (a2,b2,c2): T₁, foliar treatment with Trichoderma consortium suspension, 10⁶ cfu/mL, equiv. to 10¹¹ spores/ha; (a3,b3,c3): T₂—foliar treatment with Trichoderma consortium suspension, 10⁸ cfu/mL, equiv. to 10¹³ spores/ha; (a4,b4,c4): T₃, foliar treatment with a reference product, consisting of plant extracts, essential oils and fatty acids in an oil/water emulsion, and extract of the seaweed Ascophyllum nodosum, equiv. to 3 L/ha. Ch—chloroplast; Va—Vacuole; St—Starch grains; N—nucleus; a,b,c—different magnifications.