Studies on the pollination of pepper. III : The occurrence of abortive pollen (Agriculture)

トウガラシの授粉に関する研究の一部として不稔空虚な花粉粒の発現についての調査を行なつた。不稔花粉発現率は, 春秋の比較的低温の時期には5∿10%にすぎないが盛夏期には50%に達する。人為的にさらに高温下におくと不稔花粉は一層増加し, 高温の影響によつて発現することが明らかである。また開花15日前頃の気温と平行的関係にあることから, 不稔の機構は高温による花粉母細胞の分裂異常によるものと推察される。種間差異をみると, トウガラシの不稔花粉発現率はナス・トマトに比較してはるかに高く, 盛夏期での不結実および授粉能率低下の原因のひとつとなつているものと思われる。品種間では在来品種が洋系品種より発現が少なかつた。窒素施肥の多少は影響がみられないが, 相当生育してのちに供給が急減した場合には一時的にかなり高率の不稔がおこつた。樹令すなわち播種期による影響はほとんどみられなかつた。This paper deals with the occurrence of abortive pollen grains of pepper in its growing season and the relation to some environmental factors. The ratio of abortive pollen grains increased and reached to fifty per cent in hot season while about ten per cent in other season, and much increase of them was observed when the plants had been placed in artificially high temperature condition. The above facts show that the abortive pollen are caused by high temperature. High temperature seems to affect the meiotic division of pollen mother cells to be irregular, because the percentage of abortive pollen grains was closely related with the temperature of 13-17 days before anthesis. Percentage of abortive pollen grains of pepper is so much higher than that of egg-plant, tomato or cucumber in hot season, and, in pepper, percentage of abortive pollen of foreign varieties is higher than that of native varieties. The effect of nitrogen nutrition was not clear unless the abrupt deficiency of nutrition happened after many flower buds were developed. From the results mentioned above, in pepper, it may be considered that one cause of the deterioration of pollinating efficiency is due to high percentage of abortive pollen occurring in hot season.departmental bulletin pape