芒果炭疽病潛伏與乙烯相關性之研究

Relationships between the latent infection of mango (Mangifera indica L.) anthracnose and ethylene

張錦興(Chin-Hsing Chang)

指導教授 ： 楊雯如 ； 林宗賢

國立臺灣大學/生物資源暨農學院/園藝學研究所/博士(2012年)

https://doi.org/10.6342/NTU.2012.00479

摘要

愛文芒果是臺灣近年來極力推動外銷的果品，然炭疽病一直是產業上棘手的問題，因此本研究謹就臺南地區愛文芒果於果實生育期間進行田間接種，配合乙烯與其作用抑制劑1-MCP處理，探究芒果炭疽病害侵染與潛伏感染的情形，期以提供防治策略之參考。試験結果顯示：愛文芒果小果期以105conidia/mL炭疽病孢子懸浮液濃度無論於田間或以離果接種皆可有效侵染發病；保濕(100% R.H.)10分鐘以上、或當果皮受傷或被乳汁汚染則罹病容易。自花期至果實成熟期皆易受炭疽病菌侵染與潛伏，尤其以盛花期接種炭疽病菌致使2/3以上的花穗無法著果，隨後能著果之果穗其落果率高達61.1%，成熟期果實採收其罹病最嚴重，說明愛文芒果炭疽病防治最關鍵時期為盛花期，基本田間防治工作應於盛花期前開始。
芒果果實於不同生育期採收後接種，若處理乙烯則促進侵染發病、1-MCP處理則抑制病害發展，切片觀察乙烯促進孢子附著、形成附著器與侵入釘，1-MCP處理則否，推測可能是乙烯處理促進病害而1-MCP處理抑制病害的原因。小果期接種炭疽病菌後定期採收處理乙烯與1-MCP探討其對潛伏病害的影響，發現處理乙烯促進後熟度、罹病率、罹病面積，1-MCP處理抑制罹病率，卻無法抑制罹病面積擴大。同時，無論果實採收後接種(侵染)或果實接種後採收(潛伏)試驗處理，小、中果期果實採收後後熟晚而發病早，成熟果期採收後後熟早而發病晚，後熟與病害二者發生時序不一。測定果實接種後經乙烯或1-MCP處理其呼吸率與後熟度曲線與對照組無顯著差異，證明乙烯或1-MCP處理不影響果實呼吸率與後熟度而影響罹病情形，但促進果實後熟度有助病情發展，說明乙烯直接促進芒果炭疽病菌侵染，並影響果實後熟度而改變其侵染行為。最後，另以成熟果配合溫湯與1-MCP處理，但仍無法達到完全防治炭疽病的效果。
綜合上述，愛文芒果在採後階段對炭疽病的反應複雜，各種防治處理效果不易呈現，建議應著重在採前的田間管理最為重要，特別是盛花期之前。

關鍵字

芒果 ； 炭疽病 ； 盛花期 ； 果實生育期 ； 乙烯 ； 侵染 ； 潛伏感染

並列摘要

Of all the problems in the mango industry, anthracnose is the most difficult one to solve. To improve mango anthracnose management in Taiwan, it is an important issue to understand the critical timing when anthracnose pathogen invades mango panicles. Also, the anthracnose pathogenesis affected by ethylene may be a clue to solve this problem. In this study, panicles and fruitlets of ‘Irwin’ mango were inoculated with conidial suspensions at different developmental stages and treated with ethylene or the reaction inhibitor, 1-MCP.
The concentration of anthracnose conidial suspension used in the experiment was 105 conidia/mL and fruitlets whether detached from trees or not were always infected. Fruits in 100% RH for more than 10 minutes, with wounds or latex contamination on the peel all favored the infection of anthracnose.
Invaded panicles at the full blooming stage resulted in 67.2 % of panicles without setting any fruit and 61.1 % of the fruitlets dropped in the remaining. The highest latent infection rate in the unripe fruits while the highest infection rate and largest infected area presented in the ripe fruits during the postharvest stage. The results were indicated that full blooming stage was the critical stage for C. gloeosporioides management, and suggest that controlling the pathogens population of field before full blooming stage should be emphasized in routine practice.
Fruitlets at different developmental stage inoculated by conidial suspensions, the infection was promoted by ethylene treatment but inhibited by 1-MCP treatment. The observation of mango tissue slices indicated that ethylene but not 1-MCP induces the attachment of anthracnose spores and the formation of appressoria and penetration peg. Ethylene was suggested to be the inducement in anthracnose pathogenesis and the infection would be ceased by 1-MCP. Fruits inoculated at fruitlet stage, harvested at later different developmental stages and treated with ethylene had higher infection rate, larger infected area and faster ripening rate, and the fruits treated with 1-MCP had lower infection rate but similar infected area to ethylene treatment. Lesions began to develop on the fruits harvested at fruitlet stage was prior to fruits ripening but developed later than ripening on the fruits harvested at mature stage. No significant difference was observed on the respiration rate of mango fruits treated or untreated with ethylene,1-MCP after inoculation, neither after fruit ripening. The results showed ethylene did play an important role in latent infection, but some phenomena such as ingredients changes, flesh softening and respiration rate rising, the character of mango fruits physiology induced by ethylene, shall be involved. Since the more fruits ripened, the more infection symptom developed on the mango fruits’s peel. The following conclusion can be drawn from this study that ethylene promote the mango anthracnose infect directly, and then induces the fruit ripen that made anthracnose infected more easily. Another experiment was undertaken on mature Irwin mango by both 1-MCP and hotwater treatment in simulated shipping condition, and it was not effective to free from the threat of anthracnose.
Due to the complex reaction in Irwin mango to defend the invasion of anthracnose, it is suggested that the better timing to control the disease is on preharvest stage, especially before full blooming stage, rather than on postharvest stage.

並列關鍵字

mango ； anthracnose ； blooming ； fruit development ； ethylene ； pathogenesis ； latent infection

參考文獻

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