Fig. 2

Vascular phenotype of vasc1–1 and vasc1–2. a Illustration of spike (including peduncle), last leaf, last node and penultimate internode. Blue arrow shows where cross sections were made. b Cross sections in WT stem. c Vasc1–1. d Vasc1–2. e Vascular bundle (VB) of WT. VB and phloem area from WT are delineated in orange and blue, respectively (bottom). f Amphivasal VB in vasc1–1. VB and phloem area from vasc1–1 are delineated in orange and blue respectively (bottom). g Three anastomosed VBs in internode from vasc1–1. h VB from vasc1–1. i Magnification of h in the phloem area. White arrows show abnormal phloem cells. Blue arrows show enlarged lignified mestomes cells adjacent to phloem area. j, Two anastomosed VBs in vasc1–1. k Small VB inserted into the phloem tissues of large VB (vasc1–1). l Misplaced VB in vasc1–2. m VB in vasc1–2. Arrow show abnormal phloem tissues. n Scanning Electron Microscopic picture of m. o Focus on phloem area of (n). All sections were stained with phloroglucinol-HCl except n and o. p Number of VBs in WT and mutants penultimate internodes as shown in b. Letters above histograms indicate significant differences (p < 0.05) between genotypes after Tuckey’s pairwise test (n = 17). q Percentages of amphivasal or anastomosed VBs in the WT, vasc1–1, vasc1–2. (r) Ratio of phloem area versus the whole VB area in typical collateral shaped VBs in WT, vasc1–1, vasc1–2. Letters above histograms indicate significant differences (p < 0.05) between genotypes after Tuckey’s pairwise test (n = 6 plants, each section comprised from 17 to 24 VBs)