(第31號)稻穗傾垂後再立穗的原因研究(第一報-於民國56年發生部份)

Abstract

於民國56年秋，在臺南市安南區及其附近7鄉鎮的三年輪作水田（夏作），首次大規模發生稻穗傾垂後再立穗的現象。 因在8月29日子夜，輕度颱風娜拉的中心掠過臺灣北部後幾天，再度挺起的稻穗顯然增多，所以大家認為颱風為害的。 然而筆者乃以(1)颱風為害，(2)螟蟲加害，(3)穗頸稻熱病等的害及(4)在出穗後罹患嚴重的窒息病，且使稻穗受了二價鐵等的中毒等再立穗直接原因的4種假說作為研究目標，而以再立穗發生情況及水稻栽培環境等將近20項目，對代表地點詳加追究；並採集病株樣品，用顯微組織化學方法檢驗中毒情況，及稈、節的貯藏澱粉向穗部轉流作用受阻情形；且對穗部檢查病菌存在與否的結果，其要點如下： A mysterious phenomenon that the sagged rice panicles lifted up again was observed in the 3-Year-Rotational Rice Cropping Plots of Tainan Area, South Taiwan, in 1967. The total damaged area was 1,778 hectares. This rare sterility of rice panicle caught the farmer’s attention several days after the weak typhoon, and therefore was considere as typhoon damage by the farmers in the area. The above interpretation was, however, questioned by the author so the following four hypothetic causes of the occurrence of the “relifting-head” were taken as the bases for this research to detemine the real cause: