影響魚腥草機能性成分之因子

魚腥草(Houttuynia cordata Thunb.)富含營養及機能性成分，具開發及應用潛力。為提升魚腥草產量以及品質，本研究擬探討組織與葉片節位與機能性成分之關係，以及光質、氮肥濃度與外施水楊酸及茉莉酸甲酯對魚腥草生育及機能性成分之影響。在組織與葉片節位，將魚腥草分為上位葉、中位葉、下位葉、莖及根。結果顯示，下位葉之DPPH自由基清除率最高，且總酚類物質含量最豐，根則最低。綠原酸也是於葉中含量最豐。總結以上，根部為機能性成分較少的部位，下位葉則為組織中機能性成分含量最豐富的部位。在光質的部分，試驗結果顯示各光質處理不會造成植株外觀和生長的差異，且對生物量沒有顯著影響，然而藍光處理能增加抗氧化物質的含量，總酚類物質以及綠原酸含量均比其他處理增加約30%。因此在不影響品質的狀態下，建議於室內或是溫室補光栽培魚腥草，可以使用藍光做為光源，以增加抗氧化物質。在氮肥濃度的部分，未施加氮肥處理對植物生長效果最差，但在缺肥的逆境下，抗氧化物質濃度有上升的現象。施加氮肥處理之間於生長與抗氧化物質含量沒有顯著差異，推論可能是處理時間不夠造成，不過10、15 mM處理在抗氧化指標上，有較高的測值，對比一般肥料的氮磷鉀比例也較相近。另外，過高的氮濃度反而造成抗氧化物質下降。因此在不影響產量以及固定其他肥料配方比例狀態下(磷為6 mM、鉀為4mM含微量元素)，建議氮肥濃度為10-15 mM，以增加抗氧化物質。最後探討外施藥劑影響。不同濃度的水楊酸(0、0.25、0.5、1及2 mM)，對生長指標包含植體鮮乾重、SPAD、NDVI及葉綠素螢光測值均沒有顯著性差異，但1 mM以上的施用會使葉片生長較慢。無論澆灌或是噴施，不同濃度沒有顯著性的差異。抗氧化指標的部分，總酚類物質含量以外施0.5 mM水楊酸為最高，噴施或澆灌沒有差異，而綠原酸含量沒有差異。因此考慮到施用方便性以及植株狀態，推薦以澆灌0.5 mM水楊酸為最佳。不同濃度的茉莉酸甲酯(0、0.25、0.5、1及2 mM)施用，觀察植株外觀，各濃度間與施用方式都沒有太大差異，但高於1 mM組較易受蟲害和感病。植物的乾鮮重、SPAD、NDVI及葉綠素螢光測值，不同濃度以及施用方式，也都沒有顯著性差異。抗氧化指標方面，噴施組不同濃度處理間沒有差異，澆灌組則以2 mM處理總酚類濃度及含量較佳。綜合以上結果，外施藥劑於魚腥草，建議以澆灌方式。水楊酸濃度為0.5 mM；茉莉酸甲酯濃度為2 mM。採取的葉片節位或組織，栽培時的光質、氮肥濃度或是外施化學物質均會影響魚腥草生育及機能性成分，本論文藉由相關試驗建立栽培魚腥草之最適條件，期望能提升於藥草產業的潛力以及總體效益。

關鍵字

魚腥草；抗氧化；光質；氮肥；外施藥劑

並列摘要

Houttuynia cordata Thunb. is rich in nutrient and functional constituents, and it’s valuable for industrial application. In order to improve the quality and yield of pig thigh, the antioxidant activity in different tissues and leaf position were studied and followed by the effect of light quality, nitrogen concentration and exogenous salicylic acid and methyl jasmonate application on growth and endogenous compounds of pig thigh. First of all, in the part of different tissues and leaf position, the samples were divided to five parts, upper leaves, middle leaves, lower leaves, stem and root. Results showed that the DPPH scavenging activity and the total phenolic compounds were highest for lower leaves and lowest for root. Chlorogenic acid was highest in leaves. To sum up, lower leaves contained more functional constituents and less for root. Secondly, in the part of light quality, results showed that there was no significant difference for the plant growth and biomass for all treatments. Blue light increased total phenolic compounds and chlorogenic acid for 30% compared to other treatments. Blue light is suggested to be the light source for indoor cultivation and supplement light for greenhouse to improve functional constituents. Thirdly, in the part of nitrogen concentration, results showed that there was no effect on plant growth without nitrogen fertilization. The antioxidant indices were higher due to the stress of nutrient deficiency. There was no significant difference for growth and antioxidant indices for treatments of different nitrogen concentration applications because the period of treatment maybe was too short. The antioxidants were highest for 10 and 15 mM treatments which were similar with normal fertilization formula. Furthermore, the antioxidants were decreased for higher nitrogen concentration applications. To sum up, the nitrogen concentration fertilization without adjustment for other elements in formula (6 mM phosphate, 4 mM potassium, trace element added) is suggested to be 10 to 15 mM to improve functional constituents. The last part of this study is about the effects of exogenous salicylic acid and methyl jasmonate application on growth and endogenous compounds. In the salicylic acid experiment(0、0.25、0.5、1 and 2 mM), there was no significant difference for plant fresh weight, dry weight, SPAD, NDVI, and Fv/Fm value. The development of leaves was retarded for 1 mM and higher concentration. The total phenolic compounds were most for 0.5 mM treatment. There was no significant difference between foliar application and drench. In methyl jasmonate experiment(0、0.25、0.5、1 and 2 mM), there was no significant difference for application concentration and method in plant growth indece. The total phenolic compounds were most for 2.0 mM treatment with drench. The results suggest that the optimum exogenous application of salicylic acid is 0.5 mM for drench and methyl jasmonate 2.0 mM for drench. The functional constituents were affected by the different tissues and leaf position. Moreover, the growth and the functional constituents of pig thigh were also affected by light quality, nitrogen concentration and exogenous salicylic acid and methyl jasmonate application. This study established the optimum cultivation conditions for pig thigh cultivation and elevated the overall benefit of medical industry.