Figure 1.

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Photographs showing development of single-node cuttings of potato plants grown in vitro on various media after 10 d of culture. Each photograph, except D, shows one to five representative cuttings for a culture condition. A, Tuber-inducing treatment with 8% Suc in the nutrient medium. B, Noninducing treatment with 1% Suc. C, Noninducing treatment with 8% Suc plus 0.5 μm GA_4/7. D, A series of Suc concentrations: 8, 6, 4, 2, and 1% from left to right. E, 8% Suc plus 0.01 μm GA_4/7. F, 8% Suc plus 0.03 μm GA_4/7. G, 8% Suc plus 0.1 μm GA_4/7. H, 8% Suc plus 0.3 μm GA_4/7. I, 8% Suc plus 1.0 μm GA_4/7. J, Formation of secondary stolons after transfer of the cuttings from 8% Suc medium to 8% Suc plus GA_4/7 medium at d 5 (the bottom cutting) or at d 10 (the two top cuttings) and further culture for 5 d. K, Formation of secondary tubers by transferring cuttings first from 8% Suc medium to 8% Suc plus GA_4/7 medium at d 5 and then back to 8% Suc medium at d 10 and further culturing for 5 d. The short arrow points to the first tuber and the long arrow points to a secondary one. L, 8% Suc plus ABA. M, 8% Suc plus IAA. N, 1% Suc plus ABA; arrow indicates the short stolon. O, 1% Suc plus IAA. P, 8% Suc plus GA_4/7 plus ABA. Q, 8% Suc plus GA_4/7 plus IAA. R, 8% Suc (top line) and 8% Suc plus BA (bottom line).