Abstract
Living-pollen grains of angiosperm Styrax japonica were heated at 65 to 285℃ for 24 hours under the atmosphere in the laboratory to investigate the changes in physical and chemical properties of pollen by artificial heating experiments. It was shown that the heated pollen-grains have decreasing trends in weight, size, the atomic H/C ratio and brightness (stTAI) with increasing heating temperature, but an increasing trend in atomic N/C ratio as was known for fern spores and gymnosperm pollen. The decreasing trend of the atomic H/C ratio in the heating experiments indicates that hydrocarbon generation from pollen wall, sporopollenin, should take place in the range of heating temperature between 132 and 242℃. It is concluded that the features of angiosperm pollen, especially its brightness (stTAI) may be useful as a possible indicator for organic maturation like those of other kinds of plants.
