Activity of the CycB1;1:GUS marker of cell divisions in the leaves of WT and the tae mutant at different stages of ontogenesis. (a–c) 7-day-old seedlings of WT (a) and tae mutant grown at 22–24°С (a, b) and 18–20°С (c) express the transgene in the apex and base of the first true leaves ((b) the arrow points to fully colored rudiments of the second pair of true leaves). (d–f) 14-day-old WT (d) and tae (e, f) mutant plants grown at 22–24°С (d, e) and 18–20°С (f) express the transgene in the apex; leaves of WT (d) and mutant (e) at 22–24°C, reaching a size of 1 mm, stop the expression of the transgene; at 18–20°C (f) in the leaves of the mutant, the expression of the transgene is detected in leaves 5–10 mm in size, in young upper leaves (the tab shows a greater increase), the expression of the transgene is detected not only at the base, but also in the center of the leaf primordium; (g–h) mature leaves of flowering mutant plants grown at 18–20°C (arrows indicate expression concentrated along veins and areas where outgrowths begin to develop). The cotyledons are marked with an asterisk. Bars correspond to 0.1 (a‒c), 1 mm (d–f), and 1 cm (g, h).