雨水花園可食植物耐淹水指標、篩選及延緩逆境方法之探討

雨水花園透過匯流周遭雨水以減少逕流洪峰，若能將可食植物融入雨水花園中，並利用雨水花園本身蒐集的雨水灌溉作物，可增加雨水花園作物的多樣性及增加功能。能應用在雨水花園的植物需具一定耐淹水能力，並能適應乾溼交替。本研究考量欲探討植物耐淹水指標，以及判斷植物是否耐淹水的篩選方法，後續思考到未來雨水花園栽種不同植物之可能性，並確認其適合之種植苗齡，以及針對不耐淹水植物的降雨前維護管理措施，透過香草植物淹水之生長及抗氧化系統變化，接著以此為基礎去建立雨水花園可食植物篩選方法，進而延伸到維護管理雨水花園的概念，去探討植栽株齡選擇及減緩逆境方法。首先挑選綠薄荷、甜薰衣草及水八角進行淹水試驗，對照組作正常澆水處理，淹水處理組為將植物淹至水面高於土面2 cm，進行淹水4天並恢復正常澆水6天，期間測量其性狀及生理指標，挑選具耐淹水潛力者以應用於雨水花園。結果顯示，水八角之莖伸長率、SPAD-502數值及NDVI數值皆呈現較高數值，可推斷其適合短暫淹水的環境，其次為綠薄荷而甜薰衣草較不耐淹水。在抗氧化酵素活性皆無顯著差異的情況下，水八角和綠薄荷的H2O2及MDA測值在淹水處理下第4天和第10天相較對照組無顯著上升；而甜薰衣草則顯著上升，顯示其處於氧化逆境。因此水八角及綠薄荷的耐淹水性較佳，較適合應用於雨水花園。而MDA相較於其他抗氧化酵素活性容易出現顯著差異，可做為後續篩選耐淹水植物指標之一。接下來挑選貓薄荷、到手香、貓鬚草、檸檬香蜂草及甜羅勒進行10天淹水試驗。另外挑選穴盤苗拔葉萵苣、皺葉萵苣進行不同水質的淹水試驗，探討淹自來水、添加鹽份之自來水及低氧處理之自來水三種水質的影響。結果顯示，貓鬚草、甜羅勒兩者較適應淹水逆境，貓薄荷、到手香及檸檬香蜂草較為不耐淹，其中又以檸檬香蜂草最不能適應，而兩種苗期萵苣皆不耐淹水。而隨著淹水時間加長，植物的逆境反應愈加明顯，對照試驗期間各天相對觀賞品質對相對MDA濃度的相關分析可以發現淹水後期及回復時的決定係數較高，此時測量較具代表性。另一方面，淹鹽水及淹去氧水相較自來水更有逆境表現。以去氧處理的自來水能能使淹水逆境表現更明顯，後續可以經此處理的水來進行淹水試驗。為判斷適合苗齡，選擇3種菊科蔬菜，苗齡分別約為1個月和3個月，同時進行淹水4天並回復正常澆水6天處理，測量其生長狀況，並比較苗齡是否影響耐淹水能力。另外，從第三章挑選較耐淹水的水八角，及第四章較不耐淹之到手香、檸檬香蜂草及貓薄荷，進行淹水前施用生長調節劑模擬雨水花園於降水事件前的維護管理，觀察施用生長調節劑對於耐淹及不耐淹植物之影響。結果顯示，2種萵苣的1個月苗對於水分較為敏感，但於回復正常澆水後，其能保持一定生理機能，3個月齡苗淹水起初較穩定，但於回復正常澆水後出現較激烈的逆境反應，而苦苣不論是1個月或3個月大小的苗皆適應淹水環境。而添加生長調節劑對於耐淹水的植物無太大影響，但不耐淹的植物不論是添加水楊酸或是褪黑素皆有良好的緩解逆境效果，但生長調節劑對於不同植物有不同的反應，各種植物適用種類需要後續更多研究來探討。台灣面臨著降雨不均的情況，雨水花園的設立能暫時貯留雨水來延遲逕流並增加生態功能，透過以上研究，期能對雨水花園產業有所貢獻，使之能加深應用在台灣的都市中。

關鍵字

雨水花園；淹水逆境；可食植物

並列摘要

Rain garden collects the surrounding rainwater to temporarily store water. If the concept of edible landscape can be integrated into the rain garden and the rainwater collected by the rain garden can be used to irrigate crops, it will increase the diversity of rain garden crops and add more functions. Plants that can be used in rain gardens need to have the ability to withstand waterlogging and be able to adapt to alternating wet and dry conditions. This research considers to explore the index of plant tolerance to waterlogging and the screening method to determine whether the plant is tolerant to waterlogging, and then consider the possibility of planting different plants in the rain garden in the future. Moreover, the research confirmed its suitable seedling age for planting, and for plants that are not tolerant to live in rain garden and develop pre-rainfall maintenance and management. It measured through the waterlogged growth of herbs and the antioxidant activity, and then establish a rainwater garden edible plant screening method based on this. Finally it extend the maintenance and management of the concept of rainwater gardens to discuss plant plants age selection and methods of plant stress alleviation. Firstly, Mentha spicata L., Lavandula × heterophylla and Limnophila rugosa (Roth) Merr. were selected for the waterlogging experiment. The control group was treated with normal watering. The plants were submerged to the water surface 2 cm higher than the soil surface is the waterlogging treatment. Both properties and physiological indicators were measured during the period, and the one with the potential to withstand waterlogging were selected to be used in the rain garden. The results showed that the shoot elongation, SPAD-502 value and NDVI value of Limnophila rugosa (Roth) Merr. had higher values, indicating that it is suitable for short-term flooding environment, followed by Mentha spicata L.. And Lavandula × heterophylla is less resistant to flooding. There was no significant difference in antioxidant enzyme activity. And the H2O2 and MDA values of Limnophila rugosa (Roth) Merr. and Mentha spicata L. did not increase significantly compared with the control group on the 4th and 10th day under waterlogging treatment; while the Lavandula × heterophylla increased significantly, which means that it is in oxidative adversity. Therefore, Limnophila rugosa (Roth) Merr. and Mentha spicata L. have better water resistance and are more suitable for rain gardens. The MDA value are more likely to occur significant differences, so it can be used as one of the indicators for subsequent screening of waterlogging-tolerant plants. Next, select Nepeta cataria L., Plectranthus amboinicus (Lour.) Spreng., Orthosiphon aristatus (Blume) Miq., Melissa officinalis L. and Ocimum basilicum L. for a 10-day waterlogging test. In addition, two varieties of lettuce at the seedling stage were tested for different water quality to explore the effects of tap water, tap water with salt, and tap water treated with deoxidization. The results showed that Orthosiphon aristatus (Blume) Miq. and Ocimum basilicum L. are more adaptable to waterlogging. The other are less tolerant to flooding. Among them, Melissa officinalis L. is the least adaptable. Two species of lettuce are not resistant to waterlogging, too. With the waterlogging time increases, the stress response of plants becomes more obvious. The correlation analysis of the relative ornamental quality of each day during the control experiment on the relative MDA concentration shows that the coefficient of determination is higher in the late waterlogging period and at the time of recovery. At these times, the measurement is more representative. On the other hand, salt-added water and deoxygenated water are more stress-inducible than tap water. Tap water treated with deoxygenation can make the performance of waterlogging stress more obvious, and subsequent waterlogged experiment can be implemented with this kind of water. In order to judge the suitable seedling age, three kinds of vegetables are tested. The seedling age is about 1 month and 3 months respectively, and treated with waterlogging treatment at the same time, measured their growth status, and compared whether the seedling age can withstand waterlogging or not. In addition, select the Limnophila rugosa (Roth) Merr., which is more tolerant to flooding from Chapter 3, and the less tolerant species from Chapter 4, and apply growth regulators before waterlogging to simulate maintenance of rain gardens before precipitation events. The results showed that the 1-month seedlings of two kinds of lettuce are more sensitive to waterlogging, but after recovery they can maintain normal physiological function. The 3-month seedlings are stable at first at waterlogging, but appear oxidative stress after recovery. The addition of growth regulators does not have much effect on plants that are tolerant to waterlogging originally, but plants that are not tolerant to flooding have a good effect on alleviating stress whether they are added with salicylic acid or melatonin, but the impact of growth regulators are different from different plants. The response of various plants to applicable species needs more following research to explore. Taiwan is facing uneven rainfall event. The establishment of rainwater gardens can temporarily store rainwater to delay runoff and increase ecological functions. Through the above research, it is expected that it will contribute to the rainwater garden industry and make it more widely used in Taiwan's cities.