| 摘要: | 菠菜是一種高經濟價值的蔬菜，屬耐寒的冷季節長日照作物，其生長和發育容易受到光質及光照因素影響使作物品質改變，進而可能導致植株提前開花結果。本研究目的為探討不同光波長及光週期對菠菜在室內栽培生長表現和生理的反應。 本研究光照設備採用LED，以白光(對照組)、紅光、藍光、紅藍光共四組光波長處理，以及長光週期(14 h)和短光週期(10 h)等條件因素，共計8種處理栽培菠菜。後收集植株的生長和開花參數及葉綠素螢光Fv/Fm、養分離子含量、葉綠素、類胡蘿蔔素、總酚含量及DPPH自由基清除效力等指標，加以判斷菠菜植株於各處理下的生長及生理影響。研究結果顯示在14 h光週期的紅光波長下，能有效提高菠菜的鮮重、乾重、葉面積，相反的以單藍光14 h栽培的菠菜則會顯著降低其鮮重、乾重、葉面積。於菠菜的第35天開花率結果中，可發現在10 h的短光週期處理下，其開花率均顯著低於14 h的開花率。其中紅光及紅藍光10 h兩組的開花率均達到完全抑制開花的效果，相反的在藍光10 h處理下卻會促進其波菜開花率，且與其它10 h處理有顯著差異。當菠菜在14 h光週期條件下無論光波長處理為何皆有開花跡象，然而紅光及紅藍光之開花率顯著低於其它14 h處理。 此外菠菜在藍光波長下栽培能有效提升其總葉綠素含量，如藍光10 h的總葉綠素含量最高，除了同為藍光波長的光週期14 h處理無顯著差異外，皆顯著高於其它處理組別。於菠菜營養成份中，光週期10 h的藍光處理硝酸鹽含量顯著最高，而當在光週期14 h藍光處理下其硝酸鹽含量則顯著最低，由此得知菠菜的硝酸鹽含量在藍光栽培下易受光週期影響，使其含量差異甚大。而菠菜的鈉及鉀的最高含量則可分別在白光14 h光週期和紅光10 h光週期兩組組別中觀察到，均顯著高於其它處理含量。針對多酚含量，結果發現在同光波長處理下，光週期14 h處理的總多酚積累均顯著高於10 h處理，其中的紅藍光無論是在10 h或14 h兩種光週期處理下，其含量分別和其它光波長處理相比均顯著最高。 由本研究的實驗結果可發現，光波長和光週期不只可以影響菠菜的生長，亦能改變其成份多寡。
Spinach is a high-value, long-daylength crop that thrives under cool conditions. Its growth and development can be adversely affected by light quality and photoperiod, which can directly result in poor crop quality and early flowering. The aim of this study was to investigate the effects of light wavelength and photoperiod on the growth and physiology of spinach plants grown indoors. Four light-emitting diode (LED) treatments were used: white LEDs (control), red LEDs, blue LEDs and red+blue LEDs. In addition, the spinach plants were grown under two photoperiod treatments: 10 h and 14 h. Data for vegetative growth, flowering, chlorophyll inflorescence (Fv/Fm), nutrient content, chlorophyll content, carotenoid content, total phenols, and DPPH activity were collected. Results showed that red LEDs with a 14-h photoperiod increased the fresh weight, dry weight, and leaf area of spinach, whereas these growth parameters were significantly reduced in spinach grown under blue LEDs with a 14 h photoperiod. With regard to flowering at day 35, results showed that regardless of the light wavelength, the flowering percentage of spinach was significantly lower in the 10 h photoperiod than those grown under a 14-h photoperiod. In particular, red LEDs and red+blue LEDs under a 10-h photoperiod were able to completely inhibit flowering. In contrast, flowering of spinach plants was stimulated in the blue LED treatment with a 10-h photoperiod, which was significantly higher than those cultivated in the other 10-h photoperiod treatments. Irrespective of the light wavelength, flowering was present in spinach plants when grown under the 14-h photoperiod treatment, however, those in the red and red+blue LED treatments produced significantly lower numbers of flowers. Results also showed that chlorophyll content of spinach increased when grown under blue LEDs. This was evident in the significantly higher chlorophyll content in spinach grown under both 10-h and 14-h photoperiods under blue LEDs, compared to the other LED treatments. Analysis of the nutrient composition of the spinach plants showed that when grown under blue LEDs with a 10-h photoperiod, the nitrate content was significantly higher than other treatments, however, when grown in the 14 h photoperiod under the same wavelength, their nitrate levels were the lowest of all treatments. This finding clearly demonstrated that, when grown under blue LEDs, the photoperiod is the key factor affecting nitrate levels in spinach. Furthermore, the highest sodium and potassium levels were found in the white LED treatment (14 h photoperiod) and red LED treatment (10 h photoperiod), respectively, which were significantly higher than all the other treatments. Analysis of the total phenol content revealed that under the same wavelength treatment, spinach grown under a 14-h photoperiod possessed a significantly higher total phenol content than those cultivated in a 10-h photoperiod. Moreover, the total phenol content of spinach exposed to red+blue LEDs in both the 10 h and 14 h photoperiods were significantly higher than all the other treatments in their respective photoperiods. The findings reported in this study demonstrated that not only are the growth and development of spinach plants affected by different light wavelength and photoperiod treatments, but their chemical composition is also significantly influenced. |
