Changes in the autofluorescence of the pollen wall during microsporogenesis and chemical treatments

Measurements were made of the spectral maximum, the intensity, and fading of the autofluorescence spectrum during microsporogenesis and of pollen after some chemical treatments in Gasteria, Pinus, Physostegia, and some other plants. Mainly the sporopollenin of the sexine and the footlayer of the pollen wall showed autofluorescence which appeared to be specific for each pollen species. The cytoplasm showed sometimes autofluorescence during the initiation of the pollen wall formation. The spectral maximum increased in wave-length and the percentage of fading decreased before the formation of the intine, but also when the intine of the pollen wall is removed. The exine of the pollen wall of Pinus disappeared gradually after treatment with a mixture of acetic acid and hydrogen peroxyde. The pollen wall of Gasteria showed a higher resistance to the chemical treatments compared with Pinus pollen.