Figure 3.
Nuclear methylation changes in pollen during different stages of its development. Column A shows the FITC fluorescence from the anti-m5C antibody. Column B shows the TRITC fluorescence from the anti-histone antibody. Column C shows a false-color image composed of the FITC image (green channel), the TRITC image (red channel), and pollen autofluorescence (blue channel). The nuclear color shows the ratio of antibody staining: the more green it is the more hypermethylated the nucleus, the more red it is the more hypomethylated the nucleus. (Bars = 10 μm.) The terms amphihaploid and amphidiploid refer to the fact that tobacco is a stable hybrid of two different species, Nicotiana tomentosiformis and Nicotiana sylvestris. Although this means that it is technically tetraploid, it behaves as if it were a diploid organism. Row 6 also shows a phase-contrast micrograph of a germinating pollen grain to indicate the position of the pollen tube (which is not fluorescent). The arrow in row 6 indicates the beginning of the vegetative nuclear fragmentation.