紅光與遠紅光比例對草莓花序誘導之影響

Abstract

本研究室已建立相對短日型草莓於植物工場果實生產的環境參數，包括花序誘導期及一般的高溫長日栽培期。‘桃園一號’及‘長柄’草莓的花序誘導期參數為溫度22/17℃、光週長13小時8週，使用的光源為螢光燈(R/FR 5.11)。在完全人工光型植物工場內生產草莓，光照及溫度控制之所需之能量為產業成敗關鍵；因此，提高能量使用效率為重要課題。本研究旨在評估LED光源與提高紅光和遠紅光比例(R/FR > 5.11)對草莓生產的優勢。 提高LED栽培光源的R: FR比例，可促進草莓的花序形成率，尤其在誘導溫度略高於合適溫度時。在光週長13小時、22/17℃下，R: FR比例高於5之螢光燈及LED處理花序形成率皆可達到100%；提高誘導溫度至25/20℃時，LED (R/FR 5.48)處理僅剩60%花序形成率，提升LED的R: FR比例至18.48時，花序形成率可回升至90%。然而，在25/20℃下，螢光燈之花序形成率仍維持100%。 在適當的誘導溫度下，提高栽培光源的R: FR比例，可以降低相對短日型草莓對長日的敏感性。在誘導溫度22/17℃、光週期為14及15小時下，螢光燈(R/FR 5.11)、LED (R/FR 5.48)及LED (R/FR 18.48)的花序形成率分別為53%和0%、100%和0%、100%和13%。試驗結果也顯示螢光燈栽培之植株對光週期變化的敏感度高於R: FR比例相近之LED處理植株。 綜合花序誘導結果，在植物工場中使用高R: FR比例之LED光源，可略微提高誘導溫度以降低溫度控制成本，延長光週可增加植物光合產量，有助於產量提高，具節能及提高產能的雙重意義。再者，以23W LED燈管取代28W螢光燈，功率消耗減少18%，更為節能，且發熱量也低，空調運作量增幅少。高R: FR比例LED光源的效用可拓展至其他需冷性作物的生產及研究。

The environmental parameters for fruit production of facultative short-day strawberry cultivars in the plant factory has been previously established in our laboratory. The floral production parameters of ‘Taoyuan No.1’ and ‘Changbin’ strawberry was 22/17℃ under 13 hr of illuminating by fluorescent light (R/FR 5.11) for 8 weeks. In fully artificial light-type plant factories, energy cost for lighting and temperature control is the key factor for the success of the production industry; therefore, promoting energy efficiency cannot be more important. This study aimed to evaluate the advantage of using LED or raising R: FR ratios (R/FR >5.11) for strawberry production. Raising R: FR ratio of LED may enhance flowering percentage particularly when temperature is slightly higher than the adequate range for floral induction. In 22/17℃, 13-hr lighting with R: FR ratio above 5, the floral induction rate was 100% whether lighting with fluorescent or LED. As the inductive temperature raised to 25/20℃, the floral induction rate reduced to 60% under LED (R/FR 5.48), whereas raising R: FR ratio to 18.48 may resume the plants floral induction rate to 90%. However, all plants at 25/20℃ under fluorescent light flowered. Raising R: FR ratio of LED may alleviate the sensitivity to photoperiod of facultative short-day strawberries. At adequate inductive temperature, 22/17℃, the floral induction rate of 14- and 15-hr daylength for the 3 light sources, fluorescent light, LED (R/FR 5.48) and LED (R/FR 18.48) were 53% and 0%, 100% and 0%, 100% and 13%, respectively. The result also showed that facultative short-day strawberries under fluorescent light was more sensitive to higher photoperiod than LED with the similar R:FR ratio. In conclusion, LED with higher R:FR ratio could effectively induce flowers at temperature slightly above adequate, and thus reduce cost for temperature control. In addition, LED with higher R: FR ratio may also increase productivity for cultivating under prolonged daylength. Moreover, replacing 28-Watt fluorescent tubes by 23-Watt LED tubes decreased 18% of energy consumption, and the resulted heat emission was also lower, which added less burden on temperature control. The effect of high R: FR ratio LED may possibly apply to other chilling required plants.