二、四-地非致死劑量對玉米及胡瓜之毒性及殘留分析

蔣永正  蔣慕琰

農委會農業藥物毒物試驗所

   

本研究利用植株生長勢,葉綠素螢光反應,及植體藥劑殘留量測定,探討非致死劑量之二、四─地,對玉米及胡瓜之毒性,及免疫分析在藥害診斷技術之可利用範圍。二、四─地萌後噴施於2-3葉之胡瓜及玉米植株,定期調查植株藥害徵狀,株高、葉數、鮮重等生育性狀,及葉片葉綠素螢光變化,並配合植體殘留量之檢測。240 g ha-1劑量噴施玉米植株,未造成明顯的外觀形態異常,及生育抑制現象;藥劑殘留量於噴後四小時測得7.64 ± 0.51 g gfwt -1,三日後消退至3.95 ± 0.21 g g fwt -115日後仍可測得0.74 ± 0.06 g gfwt -1為對照株的6.2倍,三星期左右兩者測值相近。120 g ha-1劑量施用於胡瓜,主要造成噴施時已展開之第二葉萎凋,及正在發育之第三葉皺縮;施藥15日之植株外觀受損達20%株高、葉數、鮮重等生育降至對照株之40-78%第二及第三葉片之葉綠素螢光:Fo值升高,Fv/FmFm/Fo值變化較小。施藥30日植株生長有恢復趨勢,但株高及鮮重仍較對照為差。植體內藥劑殘留量,噴後四小時測得6.61 ± 0.23 g gfwt -115日後降為2.61 ± 0.11 g gfwt -130日後仍可測得對照之3.91倍。免疫分析具有之高靈敏度偵測特性,對外觀徵狀不明顯之藥害診斷,提供了直接的輔助性證據。

關鍵詞:玉米、胡瓜、二、四-地、藥害、葉綠素螢光、殘留量、免疫分析。

 

 

Phytotoxic Responses of Corn and Cucumber to Sub-lethal Rate of 2, 4-D

 

Yeong-Jene.Chiang  Mou-Yen Chiang

 

Taiwan Agriculture Chemicals and Toxic Substances Research Institute,

Wufeng, Taichung, Taiwan, R.O.C.

 

Abstract

()英文摘

2,4-D is commonly used for weed control of sugarcane in Taiwan. Spraying under unfavorable field conditions often resulted in drifting and injury of crops in farmland bordering the plantation. Simple and sensitive methods for detecting of responsible agent are very useful in the diagnosis of phytotoxicity of non-target plants. In this study, we used immunochemical assay for the quantitative detection of 2,4-D in corn and cucumber. Characteristic symptoms, agronomic parameters, and changes of chlorophyll fluorescence were also investigated. Sub-lethal level of 2,4-D was sprayed over-top to potted plants at 2-3 leaf stage. Symptoms appeared on the youngest fully-expended leaves of cucumber after 2,4-D spraying with 120 g ha-1. At this rate, 2,4-D resulted in 22-60% of phytotoxicity on cucumber at 15 days after application, and changes on the chlorophyll fluorescence of cucumber leaves with a slight increase in Fo values and reduction in Fv/Fm and Fm/Fo values. Corn was lightly injured by 240 g ha-1 of 2,4-D and recovered growth rapidly. At 15 days after application, 0.74 ± 0.06 g gfwt -1 of 2,4-D was detected in corn. And residue detection in cucumber was 1.25 ± 0.07 g gfwt -1 at 30 days after application. The sensitive and specific immunoassay provided additional information on proper diagnosis of 2,4-D injury to crops.  

Key words: corn, cucumber, 2,4-D, phytotoxicity, chlorophyll fluorescence, residual analysis, immunoassay.