RNAi downregulation of
P. deltoides PdGAUT12.1
expression leads to increased phloem and vessel size. Cross sections (1 μm) of three-month-old stems of wild-type WV-94 (A-C, J-L) and PdGAUT12.1-KD transgenic lines AB30.1 (D-F, M-O) and AB30.8 (G-I, P-R) stained with toluidine blue. A Cross section of the 10th internode of stem from a wild type WV-94 plant. B, C Higher magnification of Figure A. J cross section of 20th internode of a WT stem. K, L Higher magnification of Figure J. D Cross section of the 10th internode of a stem from transgenic line AB30.1. E, F Higher magnification of Figure D. M Cross section of 20th internode of stem from AB30.1. N, O Higher magnification of Figure M. G Cross section of the 10th internode of a stem from AB30.8. H, I Higher magnification of Figure G. P Cross section of the 20th internode of stem from AB30.8. Q, R Higher magnification of Figure P. S,T Distance across phloem in stem cross section (S) and xylem vessel cell lumen diameter size (T) from A, D, and G of the 10th internode from wild type and transgenic lines. U, V Distance across phloem in stem cross section (U) and xylem vessel cell lumen diameter size (V) from J, M, and P of 20th internode of 20 WT and transgenic lines. Red arrows show ray cells and the area of cross sections exposed to higher magnification. ep: epidermis, co: cortex, sc: sclerenchyma fibers ph: phloem, c: cambium, xy: xylem, r: xylem ray cells, xp: xylem parenchyma, v: xylem vessel, p: pith. Bar = 50 μm, A to C, D, E, G, H, L; 100 μm, J, K, M, N, P, Q; 70 μm, F, I, O, R. Error bars represent SE. *P < 0.05, **P < 0.001.