• 作者： 林安秋
• 作者服務機構： 國立臺灣大學農學院農藝學系
• 中文摘要： 本研究旨在究明氣溫與日照強度對水稻光合成物質之轉運與分配之影響，供為探討本省第二期稻作結實不良之原因為目的。結果摘要如下： 1. 水稻於抽穗期行 C 光合作用後，隨即移至人工控制氣候室內培育，在自然光照條件下1日後的結果，葉部之 C 放射活性百分比以高溫區（晝一夜溫，30°-25°C）為最低，中溫區（25°-20°C）次之，低溫區（20°-15°C）為最高，二供試品種之結果一致。又遮光60%處理結果，仍以高溫區為最低，但中、低溫區，則二供試品種之結果不一，臺南五號品種以低溫區為最高，但臺中在來一號品種則以中溫區為最高。由此可見，葉部之 C 光合成物質在高溫下，易轉運而出。 2. 自然光照下，二供試品種1日後的結果顯示，高溫區約50%之 C光合成物質已自葉部轉運至稻稈中，但中溫區僅為20%左右，低溫區則為10%以下，而後隨時間之延長，中、低溫區由葉部轉運至稻稈中之量亦增，然而，10日後仍較高溫區為低。由此可見 C 光合成物質由葉部轉運至稻稈中之速度以高溫區最速，中溫區次之，低溫區為最慢。又轉運量之趨勢亦然。 3. 水稻成熟後穗部之 C 光合成物質蓄積量，在自然光照下的結果，以中溫區為最高，高溫區次之，低溫區為最低。又遮光處理結果，以高溫區為最多，中溫區次之，低溫區最為少，二供試品種之結果一致。 4. 水稻收割後，各葉位之 C 光合成物質蓄積量，並無一定傾向，大體上，以上位葉之分配較下位葉為高。 5. 綜上結果，高溫條件下 C 光合成物質之轉運速度快，轉移量多，收穫期之葉部積蓄量較少，故穀粒中之蓄積量亦較多。但低溫條件下的結果，則正與此相反。可見，中溫以上條
• 英文摘要： The purpose of this study was to clarifythe effect of air temperature and light intensityon translocation and partition of C-assimilatesin rice plants, so that to elucidate the causesof low yield of the second rice crop in NorthernTaiwan. The results were summarized as fol-lows: 1. The distribution of C-assimilates inthe rice leaves after one-day C-labelling andtemperature treatment under natural solar radi-ation condition was the lowest at high airtemperature (30°～25°C, day-night temperature),and the highest at low temperature (20°～15°C).Two cultivars showed the same trend. Thesimilar result was obtained at high temperature,however, no regular trend was observed atmedium or low temperature under 60% ofshading. 2. The translocation of C-assimilatesfrom the leaf to the culm after one-day treat-ment was about 50% of total labelling at hightemperature, 20% at medium temperature, and10% at low temperature. Then, it was increasedafter ten days at medium and low temperatures.Thus，the translocation of C-assimilates fromthe leaf to culm was faster at high temperaturethan that of low temperature. 3. The accumulation of C-assimilates inthe panicle at harvest time under natural solarradiation condition was higher at mediumtemperature than the other treatments, and low-temperature was the least. While it was muchmore at high temperature, and low temperaturewas still the least under 60% of shading. Twocultivars had same results. Thus, the optimumtemperature for the accumulation of C-assimilates to the panicle seems to be at mediumtemperature (25°～20°C). 4. The partitoning of C-assimilates inthe leaves at harvest time did not show anyregular trend. In general, it was much more atupper leaves than the lower ones. 5. In conclusion, C-assimilates was trans-located from the leaf to culm or panicle muchmore at high temperature, while at low tem-perature, lesser of that was translocated to culmand panicle but more of that was accumulatedin the leaf. Thus, the high temperature (30°～25°C) is beneficial for the translocation andaccumulation of the C-assimilates to thepanicle. No clear trend of the effect of lightintensity on translocation and distribution wasfound in this experiment. It may be consideredthat the air temperature is more responsiblefor translocation of C-assimilates than thelight intensity.
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