Fig. 4
Mature, yellowish galls of O. robiniae with starch, sections through a galls in fresh leaves. a Part of the leaf transforming into a gall (maturation phase). The cells of adaxial epidermis are colourless and clearly convex. Mesophyll cells are enlarged, with chloroplasts containing starch. The hyphae (arrow) on the edge of the leaf are visible. b Thicked wall in the central part of the mature gall. Whole mesophyll has been transformed into the colourless storage parenchyma (nutritive tissue) with amyloplasts containing big starch grains; free hand section, no stained. c, d Sections of the gall wall with starch after reaction with potassium-iodide (Lugol liquid), starch is stained on violet. c Section from the margin part of a gall wall. The cells of external epidermis (ed) are flattened and stretched. Not all cells of nutritive tissue are evenly filled with starch. d Section from the central part of the gall wall. The cells of nutritive tissue are tightly filled with starch, what well reveals the cell shapes. Abbreviation: eb - abaxial epidermis, ed. - adaxial epidermis, lc - larval chamber, m - mesophyll, s - starch, f - fungi (hyphae), vb - vascular bundle. Bar = 20 μM