氮肥種類與施用量對紫花紫錐菊生長及咖啡酸衍生物含量的影響

Abstract

紫錐菊 (E. purpurea) 為菊科紫錐菊屬多年生草本植物，原產地於北美洲，為歐美地區相當風行的藥用植物之一，且市場對其相關產品的需求日益提高。紫錐菊是少數被研究證實具有增強及刺激人體免疫系統的功效之植物，所含的活性成分包括多醣體、咖啡酸衍生物及烷醯胺，而其中最具有指標性的為咖啡酸衍生物，如卡夫塔酸 (caftaric acid)、綠櫞酸 (chlorogenic acid)、洋薊酸 (cynarin)、紫錐菊苷 (echinacoside) 和菊苣酸 (cichoric acid)。由於紫錐菊在臺灣的肥培管理資料不多，目前研究皆未考慮其咖啡酸衍生物的含量，且紫錐菊在臺灣的收穫適期目前也沒有明確的定論。本研究以紫錐菊為材料，探討不同種類的氮肥與施用量對紫錐菊的乾重、氮磷鉀吸收、總酚類及咖啡酸衍生物的影響，同時比較紫錐菊在不同生長階段成分含量的差異。試驗採完全隨機設計，處理分別為控制組 (Control, 0 g N plot-1)、化學肥料 (Chem 1, 0.40 g N plot-1)、兩倍化學氮肥 (Chem 2, 0.80 g N plot-1)、三倍化學氮肥 (Chem 3, 1.20 g N plot-1)、有機質肥料 (Org 1, 0.80 g N plot-1)、兩倍有機質肥料 (Org 2, 1.60 g N plot-1) 和三倍有機質肥料 (Org 3, 2.40 g N plot-1)，共七種處理，每處理四重複。於幼苗移植盆栽後第150和180天分別採收根部和地上部植體與土壤進行分析。結果顯示施用有機質肥料在紫錐菊採收後能增加土壤有機質含量，且具有較高的總氮、可萃取磷、鈣、鎂及錳的含量，能保持土壤肥力並維持土壤pH值。此外，全部肥料處理對紫錐菊的乾重皆沒有顯著影響。紫錐菊在開花期後仍會吸收氮、磷、鉀、鈣及鎂，並將根的鉀轉移至地上部。施用高量化學肥料會使植物體中氮和鈣的濃度較高；而施用有機質肥料有助於紫錐菊對磷和鉀的吸收，但會降低植物體中的氮濃度，不過會使紫錐菊之酚類及咖啡酸衍生物的濃度增加。綜上所述，考量紫錐菊之活性成分含量以及土壤的永續經營，施用有機質肥料為較佳的肥培策略。其中以有機質肥料處理 (Org 1) 可得到最高的酚類 (18.3 g kg-1) 及咖啡酸衍生物 (36.1 μmol g-1) 濃度。

E. purpurea, also known as the purple coneflower, is a native North American perennial medicinal herb and widely used to treat cold, sore throats, upper respiratory infections, and some inflammatory conditions for hundreds of years. The main bioactive compounds responsible for the pharmacological actions are caffeic acid derivatives (CADs), such as caftaric acid, chlorogenic acid, caffeic acid, echinacoside and cichoric acid. Few researches have investigated the relationship between the fertilizer management and the content of bioactive compounds of E. purpurea in Taiwan. The aims of this study were: (1) to investigate the effects of different nitrogen (N) fertilizers and application rates on the growth and caffeic acid derivative contents of E. purpurea; and (2) to evaluate caffeic acid derivative contents of E. purpurea in two different growth stages. The study was conducted under completely randomized design with four replications. The treatments were Control (0 g N plot-1), Chem 1 (0.40 g N plot-1), Chem 2 (0.80 g N plot-1), Chem 3 (1.20 g N plot-1), Org 1 (0.80 g N plot-1), Org 2 (1.60 g N plot-1) and Org 3 (2.40 g N plot-1). The samples of plants (shoots and roots) and soil were taken and analyzed at 150 and 180 days after transplanting (DAT). The results showed that the application of organic fertilizer could maintain pH at a relatively constant level and increase the concentrations of total N, organic matter, Mehlich Ⅲ extractable phosphorus (P), calcium (Ca), magnesium (Mg) and manganese of soil after harvesting. Moreover, there was no significant difference on the dried weight of E. purpurea in all treatments. After blooming stage, E. purpurea would uptake considerable amount of N, P, K, Ca and Mg, and transported great amount of K from roots to shoots. The high application rate of chemical fertilizer could increase the N and Ca concentrations of the plant. The application of organic fertilizer would enhance the uptake of P and K, but decrease the production of phenol and caffeic acid derivatives in E purpurea. In summary, to consider the content of bioactive compounds and sustainable development of soil, the application of organic fertilizer is a better strategy for cultivating E. purpurea. The highest concentrations of total phenol (18.3 g kg-1) and coffeic acid derivatives (36.1 μmol g-1) were found in Org 1.