植物工廠水耕栽培綠葉紫蘇之研究

紫蘇(Perilla frutescens (L.) Britton)為唇形科(Labiaceae)一年生之辛香類草本植物，其嫩葉所含揮發性精油具有特殊香氣，可供生食與調味，並為臨床常用中草藥之一。我國自日本進口綠葉紫蘇之售價高，若於植物工廠水耕栽培，則可省力地、穩定量產清潔、安全之綠葉紫蘇，故本研究探討水耕栽培綠葉紫蘇之適當環境條件，期降低進口昂貴綠葉紫蘇之需求。綠葉紫蘇(穗耕種苗公司，產品編號A697-902)於日夜溫25℃/20℃、光強度200 μmol•m-2•s-1之T5日光燈管及日夜週期16 hr/8 hr下，以非循環式水耕系統育苗，連續採收葉片至植株開花。於臺灣大學生物資源暨農學院附設農業試驗場園藝組溫控於28℃以下之溫室內，利用Johnson、Kim與Yamasaki養液栽培之單株產量，以夏作連續採收6週為最高，分別是32.7、36.5與30.1 g，春作採收6週之12.7、13.4與15.4 g次之，冬作僅可採收3週之8.4、8.2與8.7 g最低；而每期作三種養液之產量間皆無顯著差異，故挑選配製最便利之Kim為最適配方，進行後續試驗。於39、52與78 plants•m-2三種栽培密度中，連續採收5週之單株產量以密度39 plants•m-2之12.1 g為顯著最高，但78 plants•m-2之單位面積總產量820.2 g•m-2為顯著最高，故以78 plants•m-2為最適栽培密度，進行後續試驗。2012年3 - 4月在臺大生農學院附設人工氣候室自然光玻璃溫室內，以日夜溫35℃/30℃、30℃/25℃、25℃/20℃、20℃/15℃及15℃/13℃栽培綠紫蘇，連續採收3.5週之單株產量以35℃/30℃處理之9.4 g為顯著最高，但其第1次採收葉片之NO3-含量4890 mg•L-1亦顯著最高；而25℃/20℃處理之單株產量7.6 g雖較低，但第1次採收之NO3-含量僅2823 mg•L-1，且其葉長、葉鮮重、株高與根長皆為顯著最高，故以25℃/20℃為最適日夜溫。於人工氣候室26℃人工光源室內，以不同光強度之紅光、藍光、綠光、紅藍光、紅綠光、藍綠光與紅藍綠光之發光二極管(light-emitting diode，LED)及T5日光燈管栽培，其中光強度100 μmol•m-2•s-1之紅藍光與115 μmol•m-2•s-1之紅藍綠光LED，其單株產量分別為顯著最高之12.5 g與12.7 g。另於臺大人工光型植物工廠內，日夜溫25℃/20℃與光強度100 μmol•m-2•s-1下，在日長12 hr時，8R1B、7R2B、6R3B、7R1G1B與2CW6R1B之LED及T5日光燈管中，以6R3B之單株產量6.2 g、單株採收葉片總數7片與單株根重5.4 g皆為顯著最高；而日長16 hr時，四種光源中，7R2B、6R3B與7R1G1B之單株產量皆高於對照組T5日光燈管，而7R2B之葉重、SPAD讀值與根重皆為顯著最高。於2012年1月19日(春初)及2012年4月6日(春末)在臺大太陽光型植物工廠內，以Kim養液、栽培密度56 plant•m-2及循環式水耕種植綠紫蘇，春末種植、連續採收4週單株產量7.6 g顯著高於春初種植、連續採收5週之6.7 g；且二者所採收葉片之SPAD讀值均顯著高於市售葉片；而春末種植之紫蘇醛含量顯著高於春初種植者。故綠紫蘇適合利用Kim養液與栽培密度78 plants.m-2，在臺灣夏季水耕栽培於控溫28℃以下之溫室內。於人工光型植物工廠，則適合以日夜溫25℃/20℃、100 μmol•m-2•s-1之7R2B LED及日長16 hr栽培，單株可採收葉片總鮮重11 g。而相較於營養生長期之葉片，自開花植株之小葉所萃取精油中含有較高量之紫蘇醛與檸檬烯。

關鍵字

養液；栽培密度；溫度；光質；發光二極管；光週期；硝酸根離子

並列摘要

Perilla (Perilla frutescens (L.) Britton) is an annual culinary herb of Labiaceae. The young leaves of perilla contain volatile essential oil with special aroma, and are eaten raw, or used as flavor and Chinese herbal medicine. Hydroponic cultivation in plant factory can labour-savingly produce clean and food-safe perilla leaves. This research aimed on optimal environmental conditions for hydroponically cultivating green-leafed perilla to decrease the demand for expensive imported products. Green-leafed perilla (Spike Seeds, A697-902) were sown under non-circulating hydroponic system at 25℃/20℃ with 200 μmol•m-2•s-1 of T5 fluorescent lighting and 16hr photoperiod. After transplanting, leaves were continuously harvested until flowering. Experiment of nutrient solutions were conducted in the greenhouse controlled below 28℃ of the Horticulture Section, the Experimental Farm, College of Bioresources and Agriculture, National Taiwan University. Yields per plant after harvesting for 6 weeks of green-leafed perilla treated with Johnson, Kim and Yamasaki nutrient solutions were 32.7, 36.5 and 30.1 g in summer, followed by 12.7, 13.4 and 15.4 g in spring, and 8.4, 8.2 and 8.7 g in winter, respectively. Non-significant difference existed among yields of 3 nutrient solutions in each season. Kim solution is selected for easier preparation and applied in the following experiments. Among planting densities of 39, 52 and 78 plants•m-2, 39 plants•m-2 exhibited the highest yield per plant of 12.1 g after harvesting for 5 weeks. However, 78 plants•m-2 showed the highest yield per unit area of 820.2 g•m-2. Green-leafed perilla plants were then treated by day/night temperatures 35℃/30℃, 30℃/25℃, 25℃/20℃, 20℃/15℃, and 15℃/13℃ in the natural light-glass rooms of NTU Phytron from March to April, 2012. Treatment of 35℃/30℃ showed the highest yield per plant of 9.4 g after harvesting for 3.5 weeks, but also the highest leaf NO3- content 4890 mg•L-1in the first harvest. However, the treatment of 25℃/20℃ exhibited the highest length and fresh weight of leaves, plant height and root length with yield of 7.6 g•plants-1 and NO3- content of 2823 mg•L-1. In the artificial light room of NTU Phytotron with 26℃ and 16 hr photoperiod, green-leafed perilla were treated by red, blue, green, red-blue, red-green, blue-green, red-blue-green of light-emitting diode (LED) and T5 fluorescent light. Red-blue LED with 100 μmol•m-2•s-1 and red-blue-green LED with 115 μmol•m-2•s-1 showed the highest yield per plant of 12.5 g and 12.7 g, respectively. In the closed type plant factory with 25℃/20℃ and 12 hr photoperiod, green-leafed perilla plants were treated by LED of 8R1B, 7R2B, 6R3B, 7R1G1B and 2CW6R1B and T5 fluorescent light (as control). 6R3B exhibited the highest yield per plant of 6.2 g, most harvested leaves of 7, and highest root fresh weight of 5.4g. While under 16 hr photoperiod, yields per plant of 7R2B, 6R3B and 7R1G1B were significantly higher than that of control. 7R2B also exhibited the highest fresh weight, and leaf SPAD value and root weight. Green-leafed perilla plants were grown in semi-closed type plant factory on Jan. 19th (early spring) and Apr. 6th, 2012 (late spring). Yield per plant in late spring was 7.6 g which was significantly higher than that in early spring. Length, width, fresh weight and SPAD value of leaves of green-leafed perilla plants grown in semi-close plant factory were significantly higher than those sold in the supermarket. Perillaldehyde contents in the leaves produced in late spring were higher than those in early spring. In conclusion, Kim nutrient solution and planting density 78 plants.m-2 were suitable for growing green-leafed perilla in the greenhouse controlled below 28℃ in the summer of Taiwan. In the closed type plant factory set with 25℃/20℃, 16 hr/8 hr, and 100 μmol•m-2•s-1 of 7R2B LED, 11 g of fresh leaves per plant could be harvested. The essential oil extracted from small leaves in the flowering plants contained higher perillaldehyde and limonene contents than those in the vegetative growth stage.