Figure 4.

Northern-blot analysis of mRNA derived from vegetative and reproductive tissues, anthers, and pollen. Vegetative tissues include: root, young leaf (sink leaf), old leaf (source leaf), and stem. Reproductive tissues (open flowers) include: sepal, petal, stigma, style, ovule, and nectary. Also shown are anthers with male generative gametophytes at successive developmental stages: meiosis; tetrad; unicellular; bicellular, late bicellular, and mature (immediately before anther dehiscence); and mature dehisced and germinated pollen (after 13 h of in vitro germination).