Figure 10.

Vascular anatomy of inflorescence stems in various secondary development mutant and transgenic lines.

(A–E) Xylem (xy) and phloem (ph) are intercalated in the pxy mutant, and the phenotype is enhanced by the pxl1 and pxl2 mutations. (A) WT Col; (B) pxy; (C) pxl1 pxl2; (D) pxy pxl1; (E) pxy pxl2. F–J) wox4 and wox4 wox14 double mutants have less secondary development but show no vascular organisation defects. (F) WT Col; (G) pxy; (H) wox4; (I) wox4 wox14; (J) pxy wox4. K–O) In comparison to wild type and pxy, erf109 erf018, pxy erf109 and pxy erf109 erf018 vascular tissue demonstrates a reduction in size. x is xylem, pc is procambium, ph is phloem. (K) WT Col; (L) pxy; (M) pxy erf109; (N) pxy erf018; (O) pxy erf109 erf018. P–T) Vascular organisation is perturbed in pxy and the phenotype is more severe in pxy er lines. (P) WT Col; (Q) pxy; (R) er; (S) pxy er; and (T) er erl1 erl2. U–W) Brackets enclose cambial cells; arrowheads mark phloem (Ph) cells directly touching xylem (Xy) cells. The dotted line in (W) indicates discontinuity of xylem regions. (U) WT Col; (V) epfl4 epfl6; (W) epfl4 epfl6 tdr. X–Z) Compared with WT, mol1 and rul1 show increased and decreased secondary growth, respectively. Brackets enclose cambial cells. (X) WT Col; (Y) mol; (Z) rul. AA–EE) Vascular bundles of rev-10d (BB) and rev-δmiRNA (CC) stems are often radialized and amphivasal, with xylem tissue (arrowheads) surrounding phloem tissue (ph). Vascular bundles in kan1 kan2 kan3 stems (DD) also exhibit an amphivasal pattern, with xylem (arrowheads) surrounding phloem (ph). rev phb phv displays a radialized amphicribral vascular bundle, where phloem (arrowheads) is surrounding xylem tissue (xy). (AA) WT Ler; (BB) the semidominant gain-of-function REV allele, rev-10d; (CC) miRNA resistant rev-δmiRNA; (DD) kan1 kan2 kan3; (EE) rev phb phv. FF–HH) Gaps in the bp vascular ring (arrows) are associated with stripes of ectopically lignified epidermal/cortical tissue. Arrowheads mark premature lignification of phloem fiber cells in primary vascular bundles. bop1 bop2 bp is similar to wild type. (FF) WT Col; (GG) bp; (HH) bop1 bop2 bp. Scale bars (A–E) (F–J) (K–O) (P–T) (X–Z) 50 µm; (U–W) 40 µm; (FF–HH) 100 µm. (A–E) reprinted with permission from Fisher and Turner, 2007; (F–J) from Etchells et al., 2013; (K–O) from Etchells et al., 2012; (P–T) from Etchells et al., 2013; (U–W) from Uchida and Tasaka, 2013; (X–Z) from Agusti et al., 2011b; (AA–EE) from Emery et al., 2003; (FF–HH) from Khan et al., 2012b. Copyright © 2007 Elsevier (A–E), © 2013 Development (F–J, P–T), © 2012 Etchells et al. (K–O), © 2013 Uchida and Tasaka (U–W), © 2011 Agusti et al. (X–Z), © 2003 Elsevier Science Ltd. (AA–EE) and © 2012 American Society of Plant Biologists (FF–HH).