本研究以綠（桃園2號）、黃及紫三種不同顏色甘藷葉片為材料，探討其葉片之吸收及反射光譜特徵，及比較添加5氨4酮－戊酸(ALA)後其葉綠素(Chl)含量及Chl a/b比值之變化，及葉綠素合成途徑之三種吡碄（PPIX、MGPP及Pchlide）之含量及其莫耳百分比之變化。結果顯示，三種甘藷葉片之Chl合成速率是：紫色＞綠色＞黃色。綠色及黃色甘藷葉片之吡碄莫耳百分比分佈相似，紫色甘藷葉片則展現不同的形態。黃色甘藷葉片對Chl a及Chl b合成的調控能力不如其它二種甘藷葉片。這三種甘藷葉片似乎可在黑暗中合成Chl。ALA對三種甘藷葉片Chl合成途徑之Pchlide莫耳百分比並無影響，對綠色及黃色二種甘藷葉片之MGPP莫耳百分比則有顯著抑制，而對三種甘藷葉片之PPIX莫耳百分比則有顯著促進。因此，這三種不同顏色甘藷葉片擁有不同的調控Chl合成之能力，而自我調適以面對環境變遷之機制也明顯不同。而這些調控機制迄今仍是謎，有待進一步研究。
This study used green, yellow and purple varieties of sweet potato as materials to explore their absorptance and transmittance spectra characters, and to compare the change of Chl content and Chl a/b ratio, and the three porphyrin contents and their mole percentages, including PPIX, MGPP and Pchlide. The chlorophyll synthesis rate was in the order of purple>green>yellow. The mole percentages of porphyrins in green and yellow sweet potatoes leaves were similar to each other, but were quite different in leaves of purple sweet potato. The regulation capacity of chlorophyll content and a/b ratio in green and purple sweet potatoes leaves were better than those in yellow sweet potato leaves. Supplementation of δ-aminolevunilic acid (ALA) did not influence the mole percentage of Pchlide in leaves of these three sweet potatoes, but it did inhibit the mole percentage of MGPP in leaves of green and yellow varieties and promoted the mole percentage of PPIX in leaves of all varieties. Results suggest that the capacity in regulating chlorophyll quality and quantity and the adaptation to environmental change of these three sweet potatoes leaves may be different. The regulatory mechanism needs further investigation.
