多效唑在桃果实中的残留量评估

 为评估多效唑在桃园中使用的安全性，于2010-2011 年分别以3 个普通桃品种为试材，使用不同剂量（0.0375 ~ 0.225 g · m^-2）、不同浓度（500 ~ 1 500 mg · L^-1）多效唑进行土壤施入或叶面喷施，利用气相色谱-三重四级杆串联质谱仪（GC–MS–MS）对成熟桃果实中的多效唑残留量进行了测定。结果表明，仅在大棚桃试验中的1 个较高浓度叶面喷施处理（1 250 mg · L^-1 喷施2 次）的桃果实中多效唑残留量超过0.5 mg · kg^-1，其它处理的残留量均小于0.5 mg · kg^-1，其中大部分土施处理的残留量低于0.05mg · kg^-1。如果以最大残留量 ≤ 0.5 mg · kg^-1（欧盟现行桃残留限量标准）为标准，按树冠投影面积，土壤施入0.0375 ~ 0.225 g · m^-2 等不同剂量，桃果实中多效唑残留量不超标；在露地条件下叶面喷施浓度不超过1 500 mg · L^-1，在大棚条件下浓度不超过1 000 mg · L^-1，喷施次数不多于2 次，果实中多效唑残留量也不超标。

Evaluation on Residue Amount of Paclobutrazol in Peach Fruits

In order to evaluate the safety of paclobutrazol applied in peach orchards，the terminal residues in mature fruits of 3 peach varieties with different dosage by soil application（0.0375–0.225g · m^-2）or different consentration by foliar spraying of paclobutrazol were investigated by GC–MS–MS in 2010 and 2011. The results showed that only one treatment with higher foliar spraying concentration（1 250 mg · L^-1 sprayed 2 times）in green-house peach experiment led to the residue amount in mature peach fruits over 0.5 mg · kg^-1，the residue amount of another treatment was less than 0.5 mg · kg^-1，most treatments of soil application was even below 0.05 mg · kg^-1. If according to MRL ≤ 0.5 mg · kg^-1 of paclobutrazol in peach（current MRL of EU），based on canopy projection area，different dosage by soil application（0.0375–0.225 g · m^-2），the residues in mature fruits do not exceed the allowed figure；Paclobutrazol applied by canopy spraying with no higher than 1 500 mg · L^-1 in open orchard or 1 000mg · L^-1 in green-house peach，and no more than 2 times，the residues in mature fruits do not exceed the standard，either.