利用植物工廠繁殖水耕草莓走莖苗之研究

草莓(Fragaria × ananassa Duch)屬薔薇科(Rosaceae)，重要小漿果類，是分佈很廣的世界性經濟作物，性喜冷涼氣候。繁殖幼苗期正值臺灣高溫雨季，在田間栽培經常遭受病蟲害侵襲，而需使用大量農藥。目前組織培養苗出瓶、上盆、健化後，還需要繁殖走莖苗，才能定植於田間。於密閉式植物工廠栽培，可隔絕病蟲害，並週年穩定生產無農藥、健康之苗株。本研究目的探討在植物工廠的動態浮根式水耕系統栽培下，建立由組織培養苗定植做母本繁殖走莖苗的技術，藉以高效率穩定的產出健康走莖苗，供田間栽培。本研究第一階段建立草莓的水耕步驟，以‘白草莓’組織培養苗出瓶，在繁殖架的潮汐式灌溉栽培盤上健化，然後定植在成長架的動態浮根式水耕溝槽中組培母株(TC)，再將其走莖壓條於隔壁的繁殖溝槽養液中，當走莖發根即剪下種植於2.5吋(5.5公分)軟盆的椰纖中，放在潮汐式灌溉栽培盤上生長。結果從走莖萌出至壓條需11.1±1.3天，發根時間為2±0.6天，當走莖根長2 cm、有2片成熟複葉時，剪下上盆的操作流程，總共22.5±1.3天，成活率為97%。兩個月繁殖試驗期間，平均每株TC產出11.7±0.1株走莖苗。試驗二繼續觀察TC的生長勢和產能，並與由壓條繁殖的走莖母本(Runner) 比較；另外進行走莖繁殖處理包括壓條方法(連續，Continue；單株，Single)和發根介質種類(椰纖，Coir；或養液，Non)，共4個處理。2個月繁殖處理結果顯示，從TC連續壓條產出27.7±7.1、單株壓條產出27.5±4.9株走莖苗，而Runner連續產出21.8±1.72、單株產出18.2±3.43株走莖苗。在不同壓條方式下，以連續壓條與單株繁殖之走莖苗，在剛從母本分離時，其葉片數分別為(3.0和2.0片)、根長(7.89和5.59 cm)、走莖數(2.7和1.4 條)、葉面積(165.32和86.95 cm2)、地上部鮮重(6.76和3.23 g)、乾重(1.21和0.60 g)及地下部鮮重(0.69和0.35 g)、乾重(0.05和0.02 g)均具顯著差異。在後續1週、3週及5週的採樣調查中，各調查項目的趨勢與剛分離之幼苗一致，均為連續壓條高於單株壓條處理。尤其以Runner母本以連續壓條使用介質(Runner + Continue + Coir, RCC)處理所得苗株之性狀，於各時期，走莖數、地上部鮮重及葉面積均顯著多於單株處理。同時在植體營養元素含量中，RCC之苗株於剛分離時，其碳氮比(C/N：16.3 %)較低，磷含量為341.0 ppm，較其他7處理顯著高，以後各週植株亦呈現相同趨勢，顯示出連續壓條之苗株有較佳之生長勢。使用椰纖介質的處理組，將填充介質之軟盆置於穴盤中，可阻擋光線照射到養液，未使用介質者，穴盤中的養液暴露於光線照射之中，造成養液滋生青苔並附著於植株根系上，進而影響植株生長。使用介質之連續壓苗方式可獲得生長勢較佳的苗株。

關鍵字

草莓；走莖苗；壓條繁殖；養液栽培；植物工廠

並列摘要

Strawberry (Fragaria × ananassa Duch), belongs to Rosaceae family, is a world-wide important economical small fruit plant, prefers cool climate. In Taiwan, daughter plants are propagated during the hot rainy season. They are often attacked by pests and diseases in the field and a large amount of pesticides are applied. The tissue culture plantlets need to be potted and hardened, and then are used to produce runner plants for transplanting to the field. If it is cultivated in a closed plant factory and isolated from external pests and diseases, it can stably produce pesticide-free and healthy daughter plants year-round. The objective of this study was to develop the technique of propagating strawberry daughter plants, using tissue cultural explants as stock plants, in a closed walk in growth chamber, on the dynamic root floating hydroponic system, in purpose of efficiently producing healthy runner plants for the field cultivation. The first stage was to establish the strawberry hydroponic method.‘White strawberry’tissue cultural plantlets were potted and laid in trays on the propagating rack using ebb-and-flow irrigation system for hardening. Then they were transplanted, to the troughs on the growth rack using Dynamic Root Floating circulating system, as tissue culture stock plants (TC). Their runners were rooted by layering in the troughs next to them with nutrient solution. The rooted runner plants were removed and potted in the 5.5 cm containers with coir fiber and returned to the propagating rack. The results showed that it took 11.1±1.3 days from runner emerging to processing layering. Rooting took 2±0.6 days. The runner was removed from the stock plant and potted when its root was 2 cm long and with 2 mature compound leaves. It was totally 22.5±1.3 days for each prapagating runner plants with 97% surviving rate. After 2 months of experiment, each TC produced 11.7±0.1 daughter plants. The second stage, continue to observe the productivity of TC plants. Meanwhile daughter plants were added to be stock plants (Runner). Two factorial experiments were conducted to compare effects of layering methods (Continue: C and Single: S) and rooting substrates (Coir: C and Non-solution only: N), which were 4 treatments. The results from 2 months of propagation, TC+C treatment produced 21.8±1.72 daughter plants, and TC+S 18.2±3.4 plants. Comparing C and S layering methods, daughter plants at separation from stock plants, their leaf number (3.0 and 2.0), root length (7.89 and 5.59 cm), number of small runners (2.7 and 1.4), leaf area (165.32 and 86.95 cm2), shoot fresh weight (6.76 and 3.23 g) and dry weight (1.25 and 0.60 g), root fresh weight (0.69 and 0.35 g) and dry weight (0.05 and 0.02 g) were significantly different. The growth 1, 3 and 5 weeks thereafter had the similar trend. The daughter plants from Runner+Continue+Coir (RCC) treatment had the highest growth. Among the plant tissue nutrient contents at separation from stock plants, RCC daughter plants had lower C/N (16.3%), higher P 341.0 ppm than other treatments. The trend persisted through the study, showed that young plants produced from layering grew faster. Treatment without coir had algae growing in the plug cell and on roots, which affected the plant growth. Coir rooting substrate could block lighting into the nutrient solution and offered a more stable environment for roots, which resulted in better quality daughter plants.