以膜熱穩定性技術評估菊花開花之熱延遲

Abstract

摘 要 (Abstract) 本論文研究主要期望建立一套適用於菊花作物的膜熱穩定性技術，並了解菊花開花熱延遲與膜熱穩定性之相關性，進而應用此技術選拔對開花熱延遲鈍感之菊花實生苗。 以25 - 70℃水浴處理夏及秋冬菊葉片，結果葉片之熱傷害值與水浴溫度呈現S曲線變化，夏菊和秋冬菊之S曲線反折溫度分別為50℃與45℃，並能區別品種熱穩定度差異。秋冬菊以1 - 2、3 - 4、5 - 6、7 - 8及9 - 10不同節位之葉片並給予45℃水浴溫度處理，以上層展開葉片較能區分品種間之熱相對傷害值，以完全展開葉第3 - 4節位為適當之取樣材料。 以50℃熱處理0 - 30分鐘時間處理時，葉片熱傷害值變化隨著熱處理時間延長而增加。以熱處理30分鐘下，夏菊品種間葉片熱傷害值差異最大。以50℃處理30分鐘來檢測在15/13℃~35/30℃溫度下生長之夏菊品種之葉片熱穩定度，結果葉片熱傷害值變化隨著生長溫度增加而降低，且在20 - 35℃下生長之植株葉片有熱馴化之效果。 於春夏季以20/15℃~30/25℃處理下，大部菊花品種在30/25℃下，有明顯開花延遲，其中‘白丁字’和‘金風車’未到達開花階段；於秋冬季種植時，在‘雙色紅’和‘卡若里’品種在25/20℃處理下，就有開花天數延遲。在春夏季時定植時，菊花花苞發育第一階段(自短日到見苞小於 2mm)時間明顯高於其他發育階段，到最後開花延遲。在秋冬季種植時日長由12.5-11.5小時變化，結果在菊花花苞發育階段，以第三階段(花苞大於1公分到顯色)發育所需時間較長。 在春夏季種植時，將夏菊四個品種葉片熱傷害值與在30/25℃、25/20℃及20/15℃下生長開花延遲天數進行

Summary Techniques for rapid and easy identification of heat tolerant genotypes in chrysanthemum were studied. The relationship between flowering delay in chrysanthemum and CMT as a measure of heat tolerance, was used to select flowering heat-delay insensitivity in chrysanthemum cultivars and seedlings. Relative injury (RI) was calculated to assess genotypic differences in CMT for chrysanthemum by measuring the electrical leakage from 25 to 70℃. Sigmoid response curve relationships were apparent between the RI values of all chrysanthemum leaf tissues under different water bath temperatures. A single temperature treatment at 50℃ resulted in RI values near the midpoint of the response curve for summer-grown chrysanthemum cultivars, as compared to 45℃ for winter-grown chrysanthemum cultivars. Leaves 1-2 to 9-10 from top were taken to measure their RI values, and genotypic differences were greatest in full-expanded leaves 3 to 4 when using CMT test. RI increased with increasing duration from 0 to 30 minutes at 50℃ water bath treatment, and the 30-min treatment exhibited the greatest genotypic differences. RI value tended to decrease with increasing temperature from 15/13℃ to 35/30℃, summer-grown chrysanthemum grown at temperatures 20 to 35℃ showed heat acclimation. CMT is a useful screening procedure for selecting heat tolerance of chrysanthemums, with 45℃ and 50℃ for 30 minutes for selecting summer-grown and winter-grown chrysanthemum cultivars respectively. Most cultivars planted grown at 30/25℃ in spring and summer seasons exhibited flowering heat delay, especially for cultivars White Ting-Tzu and Repulse did no flower within 120 days, as compared to those at 25/20 or 20/15℃. But cultivars Remix and Kaa Luoh-Lii exhibited flowering heat delay at 25/20℃ in autumn and winter seasons. Floral development spent long time on phase I, as compared to other phase in chrysanthemum planted in spring and summer season, were delay flowering at experimentation end. Floral development spent longer on phase III in chrysanthemum at daylength from 12.5 to 11.5 hours planted in autumn and winter season. Planted in spring and summer season, clear linear relationships existed when regressing the RI value on the heat delay of days to flowering in four summer-chrysanthemum cultivars planted in two day/night temperatures between 30/25℃ and 25/20℃, or 30/25℃ and 20/15℃ in phytotron conditions. Planted in autumn and winter season, linear relationships existed when regressing the RI value on the heat delay of days to flowering in five summer- and six winter-chrysanthemum cultivar planted in two day/night temperatures between 30/25℃ and 25/20℃, or 30/25℃ and 20/15℃ in phytotron conditions. The CMT of two cultivars Chiu-Yang and Tsai-Yun was measured with leaf and petal discs electrical leakage from 25 to 70℃. Similar sigmoid response curve relationships were apparent between the RI values of two chrysanthemums leaf and petal tissues under different water bath temperatures. RI values were calculated for open-pollinated seedlings from three chrysanthemum cultivars Tsai-Yun, Rong-Hung and 9721 by measuring leaf electrical leakage. Four groups could be classified according to their RI values in leaves by CMT, including group I ( 1 to 30% RI ), group II ( 31 to 50% RI ), group III ( 51 to 70% RI) and group IV ( 71 to 99% RI ). Seedlings of chrysanthemum cultivars Tsai-Yun and Rong-Hung contained groups II to IV, as compared to groups I to III in cultivar 9721. Positive linear correlations existed between floral development stage and their associated groups after planting. Faster floral development was coincident with low RI plants.