(A) Chloroplast responses to blue light in wild-type and transgenic N. tabacum cv. Samsun expressing plastin-GFP. The curves show changes in transmission of red measuring light (ΔT) through dark-adapted leaves exposed to continuous weak blue light (wBL, 0.4 Wm-2, 45 min) and strong blue light (SBL, 10 Wm-2, 45 min). ΔT [+] and ΔT [-] denote amplitudes of accumulation and avoidance responses respectively. Representative responses for about seventy tests carried out with three-month-old wild-type (a) and transgenic (b) tobacco plants. Curves c and d are representative of two-month (c) and one-month-old (d) plants. (B) Actin organization in immature mesophyll of transgenic (one-month-old) plants grown in vitro. Bar, 10 μm. (C) RT-PCR. (1) control, non-transformed plant, (2–4) three plants of T1 generation, (5–7) three plants of T3 generation. (D – G) Parameters of blue light-controlled chloroplast responses in mature leaves of transgenic N. tabacum. (D, E) Amplitudes: ΔT(+) of weak (wBL, 0.4 Wm-2), and ΔT(-) of strong (SBL, 10 Wm-2) blue light responses. (F, G) Velocities: V(+) of wBL, and V(-) of SBL responses. Averages of 7–14 measurements. Error bars represent SD. Asterisks denote the significance of differences (p-value calculated with the unpaired t-test, * p = 0,05–0,001; ** p = 0,001–0,0001; *** p < 0,0001).