樹木淺層藥劑注射技術之研發與應用

由於環境的限制，當都市林樹木發生病害時，通常較難以實施化學性的藥劑噴灑進行醫療，此時注射技術的運用是一個很好的替代方法。此方法具有 (1) 能有效地使用化學物質， (2) 減少潛在的環境暴露， (3) 當以土壤澆灌無效或難以使用葉面噴灑時有用，(4)適用於人口稠密地區等優點。以治療為目的在樹上進行鑚孔並注入藥劑的相關研究在19 世紀初期已有相當進展，運用上除了防治病蟲害以外，也擴及到營養改善、生長調節劑控制、抗病誘導等方向。對於注射操作過程所需考慮的注射位置、孔徑、深度、角度、壓力、封口、季節、藥劑、及追加注射等注意事項，隨著研究以及新事證出現，皆使得注射之技術不斷提升。本研究旨在研發符合本土運用之樹木注射技術，依照不同樹皮形式，先以100(#) 粗砂紙或直徑 3.5 公分木工取孔刀刨除木栓層，再用直徑 1 公分電鑽，刮除韌皮部露出木質部，用 2 平方公分防水膠帶貼合木質部和形成層切口後再行鑽孔注射。注射是以 0.4 公分直徑的鑽頭鑽孔，深度為 1 公分，插入刻度滴管後以矽利康搭配透氣膠帶完成封口進行滴管輸液。標準步驟為「表皮和木栓層研磨衛生處理含酒精消毒、直徑 1 公分電鑽刮除韌皮部和形成層露出木質部後貼上防水膠帶、直徑 0.4 公分電鑽鑽出深度 1 公分之注射孔、插入刻度塑膠滴管並固定、以中性矽利康封口、透氣膠帶密合防漏、注入藥液、插入尼龍繩排出氣泡、套上銀黑塑膠布保護套」，經測試防漏效果甚佳，觀察藥液之吸收也十分便利。而所費時間約 10 分鐘，是一可以接受之淺層注射技術。此為樹木解剖及生理學基礎下，符合科學、經濟、實用的樹木淺層醫療注射技術，可為專業操作者參考採用。研究調查出各樹種淺層注射主要吸收日數與劑量為：鳳凰木 2 日 9.47 毫升，楓香 8 日 24.4 毫升，龍眼 4 日 31.41 毫升，光蠟樹 5 日 37.7 毫升，莿桐 3 日 25.7 毫升，烏桕 8 日 21.3 毫升，朴樹 5 日 66.97 毫升，山櫻花 6 日 51.47 毫升，櫸樹 6 日 54.03 毫升，樟樹 7 日 56.83 毫升，榕樹 4 日 5.67 毫升，濕地松因春天松脂分泌旺盛全無吸收。當植物不再吸收時，便需將注射滴管拔除，並以封口塗劑確實將拔除滴管後遺留之孔洞封填密合，讓根壓水分順利協助藥劑運送至目標作用區域，也避免刻度滴管妨礙到注射口之癒合。三種淺層注射於木質部吸收之比較，發現基本上以弦向 45 度向下 2 公分之吸收速率最大。證明樹木的外圍生長輪吸收效率高，因此注射鑽孔不用深。而韌皮部無法吸收注射藥劑，且不同的藥劑劑型和濃度對韌皮部會有不同程度的傷害反應。注射藥劑向下運行，是藉由樹木體內橫向疏導系統，將木質部藥劑運送至韌皮部後，再由韌皮部篩管向下運送。因此，注射時應避免藥劑接觸到韌皮部和形成層以促進注射傷口癒合。利用益收和能夠抑制乙烯生合成的艾維激素對樹幹進行注射，並以水做為參考對照，以驗證 CODIT 可能的啟動因子是否即為乙烯，結果證明注射艾維激素的樣本，有較大的傷害反應。而不同樹種注射 3 個月後之傷口癒合反應調查結果，刺桐最佳，光蠟樹次之，其他樹種緩慢。原注射點追加注射實驗，觀察榕樹之吸收反應，結果證明樹木似有產生區隔化。對於必須週期性注射的操作建議，可採用本研究研發之淺層注射技術，搭配長效期藥劑，以兩年為期，每次注射皆在最外圍生長輪操作，如此便可有效降低注射過程可能對樹木造成的傷害，讓藥劑有效的吸收運行至作用目標區，達到樹木注射醫療照護目的，及衍生出的最大效益。

關鍵字

淺層藥液注射；注射吸收；傷口恢復； CODIT啟動因子

並列摘要

Urban trees are very important for improving the environmental quality of a city. They may also be a risk to the resident when they are infected by tree diseases. The purpose of a tree therapy is to keep the health of the trees and the environment so as to avoid the risk from diseased trees. However, because of the limitation of space, when the urban trees are infected they can not be cured by conventional methods as those of wild trees. At such circumstance a trunk injection is more appropriate for cure the disease. The trunk injection has many advantages including: (1) higher efficient utilization of the pesticides; (2) lower pesticide exposure; (3) a better choice when soil drenching or shoot spraying are not available; (4) suitable for residential areas. The history of trunk injection for a tree could be traced to early 19th century, when people used it to fuse the nutrition, inject a growth regulator, induce disease resistance, or conquer a disease. The injection technology was gradually improved as scientists tried more and more on the appropriate injection point, hole size, depth, angle, pressure, season, chemicals, and the timing for re-injection. This study is therefore aimed to develop a suitable shallow-layer injection technique for use at our urban environment. The trunk surfaces were polished with sand paper or a 3.5 cm drill knife to remove the cork layer and disinfected with alcohol. A 1 cm drill was used to remove the phloem layer and expose the xylem layer then a 0.4 cm radial hole was drilled for 1 cm deep for inserting a scaled PE dropper for infusing the solution. The standard operating procedures are: surface polishing and disinfection, hole drilled by an electrical drill, inserting a scaled PE dropper, sealed with sterile cotton and neutral silicon gel, to avoid leakage by a breathable tape, filling with solution, to remove air bubble by a nylon cord, and covering the dropper with a silver-black plastic envelop. The solution leakage can be completely avoided and the infusion can be quantitatively observed with this device. It takes only about 10 minute for an operation and is an acceptable injection technique for physiological or therapeutic studies for urban trees. The infusion rates for major trees measured by this technique expressed as numbers of uptake days and uptake volume are: 2 days /9.47 mL for flame tree, 3 days /19 mL for fragrant maple, 4 days /31 mL for longan tree, 3 days /34 mL for Formosan ash, 3 days /34 mL for India coral tree, 3 days /34 mL for tallow tree, 4 days /49 mL for Chinese hackberry, 6 days /52 mL for Taiwan cherry, 5 days /42 mL for Taiwan zelkova, 7 days /54 mL for camphor tree, 3 days /5 mL for banyan tree. Only the pine tree did not uptake solution because of the strong excretion of pine resin. The infusion rates measured in three injection methods at different angle/depth on trunks of banyan trees by this technique were compared with each other. Results showed that a tangential hole at 2 cm deep can uptake more than a radial hole at 6 cm deep, each with uptake days and volume of 4 days/11.3 other than 4 days/ 11.2 mL, respectively. This result proves that the transfusion at young wood region play the most important role for a tree. Therefore it is not necessary to inject into deep wood for a therapy injection. The phloem is proved to not be able to infuse directly the solution, but the solution is moved to the crosswise or lateral xylem cells first then move to the downward phloem tubes. The phloem in wound hole will be hurt by the solution especially when the concentration of chemicals is too high. The CODIT (Compartmentalization Of Decay In Trees) concept was also proposed and testified in this study, using an ethylene-producing Ethephon and an ethylene inhibitor aminothoxyvinglycine to infuse in the trunks of banyan trees and Taiwan zelkova. Results showed the injected hole of Taiwan zelkova with aminothoxyvinglycine did not show CODIT response and were injured with wood cracking symptoms. The recovery of the wound holes of 12 tree species were compared after three months. Results showed that the flame tree recovered the best, followed by the Formosan ash, and all the others. All the results exhibit that this shallow-layer injection technique is appropriate for trunk injection with long-acting fungicides that have the greater advantage and lower damage to the trees and urban environment.