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Abstract為了解光化學反射指數(photochemical reflectance index, PRI)與光系統II (PSII)效能間之關係受到葉綠素含量(Chl)及溫度之影響情形，本研究以不耐低溫的芒果為材料，選取不同葉綠素含量的葉片為對像，探討在不同溫度下的黎明及中午，其PSII效能、葉黃素循環色素 [violaxthanin (V)、antheraxanthin (A)及zeaxthanin (Z)]、PRI及Chl之關係。結果顯示，於不同光環境及溫度條件下，芒果葉片之葉黃素循環色素之總量[violaxthanin (V)+antheraxanthin (A)+zeaxanthin (Z)]與相對含量[V/(V+A+Z), A/(V+A+Z), Z/(V+A+Z), (0.5A+Z)/(V+A+Z), (A+Z)/(V+A+Z)]均與其葉綠素含量呈顯著的相關關係。顯示葉綠素含量較多之葉片，由於可吸收較多的光能，需要較高的葉黃素循環色素來消散過多的光能。而黎明或中午之PSⅡ效能與葉黃素相對或絕對含量間之相關皆不顯著，但扣除葉綠素後，其PSⅡ效能與葉黃素相對含量間便呈顯著之負相關，其中越是低溫的黎明，會累積越多的A及Z則葉片之Fv/Fm值越低。 PRI因能反應葉黃素循環色素之去環氧化態程度，亦受到葉綠素含量多寡之影響，然本研究首見，計算PRI之531及570 nm兩波段之反射率與葉綠素含量間之關係又會受到溫度之影響，即Chl較低之葉片其R531及R570均在低溫下較高，但是溫度越低，則R531及R570隨葉綠素增加而降低之幅度愈大，導致葉綠素含量較高之葉片在高溫下，其R531及R570有較高之趨勢。進一步探討PSII效能與PRI之關係，發現芒果葉片之PSⅡ效能與PRI間並無顯著之相關關係。但發現葉綠素含量相近之葉片，其PRI大致隨PSⅡ效能之升高而增加，唯PRI變化幅度以冷季較大暖季較小。由以上結果得知，PSⅡ效能與PRI之關係受到Chla+b及溫度之影響。利用複迴歸分析獲得PSII效能與PRI及葉綠素、溫度之關係，並發現此關係可用作現場植物PSII效能之推估。
The aim of the present study was to understand the influence of chlorophyll concentration (Chl) and temperature to the relation between photochemical reflectance index (PRI) and PS II efficiency. Mango, a chilling sensitive fruit tree, leaves with differential Chl were used to investigate. The result indicated that the amount of [violaxthanin (V)+antheraxanthin (A)+zeaxanthin (Z)] and relative concentration of [V/(V+A+Z), A/(V+A+Z), Z/(V+A+Z), (0.5A+Z)/(V+A+Z), (A+Z)/(V+A+Z)] of xanthophyll cycle pigments of mango leave were closely related to Chl. This was due to the leaves with high Chl can absorb more energy, and need to dissipate more excessive light energy. The PS II efficiency and PRI, both measured at predawn and noon, did not relate to the amount and relative concentrations of xanthophyll cycle pigments, but it showed significant negative correlation between PS II efficiency and xanthophyll cycle pigment concentrations per unit Chl (fig 11). Besides, more large amounts of Z and A accumulate at the predawn of lower temperature, and leading to lower Fv/Fm. PRI can reflect the degree of xanthophyll de-epoxidation and be effected by Chl. Results of the present study indicated that both of reflectances of 531 and 570 nm (R531 and R570) increased with Chl; the decrease rate of R531 and R570 were both higher at low temperature conditions. Both of R531 and R570 were influenced by Chl and temperature. The leaves with higher Chl showed higher R531 and R570 under high temperature condition. Results of the present study also showed that even there was no significant correlation between PS II efficiency and PRI, but PRI always followed PS II efficiency compared to the leaves with same level of Chl, and the variation of PRI in winter was higher than that in warm season. This result indicated that the PRI-PS II efficiency relationship was influenced by both Chl concentration and temperature. According to the multiple regressing analysis, PS II efficiency closely correlate to the PRI, Chl and temperature. We used the estimated multiple regressing equation to estimate the PS II efficiency, and to merge the data measured at predawn and noon of cold and warm days. Results indicated that model predictions fitted the measured data well value, indicating that the, multiple regressing model could be used to estimate PS II efficiency.
中文摘要．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．5 英文摘要．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．7 目錄．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．9 圖目錄．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．10 表目錄．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．12 符號表．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．13 前言．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．15 前人研究．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．17 材料與方法．．．．．．．．．．．．．．．．．．．．．．．．．．．．．20 結果．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．25 討論．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．52 參考文獻．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．57
TypeThesis and dissertation