【作者】 任志华；

【导师】 李玲；

【作者基本信息】 华南师范大学 ， 植物学， 2005， 硕士

【摘要】 柑橘贮藏期有多种病害,收获后损失很高。2,4-D混合杀菌剂处理柑橘具有杀菌保鲜效果,在柑橘业中广泛使用。但2,4-D在自然的状况下不易降解,对生态环境和人体有害。本文研究了(1).2,4-D在柑橘果实(果皮和果肉)的残留,2,4-D代谢酶2,4-二氯苯羟化酶的活性变化;(2).2,4-D处理果实后的品质变化。对了解杀菌剂施保克混合2,4-D处理柑橘后果实中2,4-D残留及代谢情况,认识柑橘果实安全性以及科学应用2,4-D提高柑橘品质有着重要现实意义。 分析从市场购买的4种常见柑橘果实品种四会桔、江西脐橙、新奇士和红江橙,测定出其中2,4-D含量在28.5 ng/g到8.1 ng/g之间,低于农业部规定柑橘类水果中的残留限量2 mg/Kg,说明市场上的柑橘安全性较高。 为确定2,4-D处理柑橘的最佳浓度,分别用200 mg/L、100mg/L、50mg/L 2,4-D处理温州蜜柑,测定处理后6h、12h、24h、36h和48h时果肉中2,4-D的残留量。结果表明,果肉中2,4-D的残留量在50ng/g至400ng/g之间,皆低于残留限量,安全性较高;而200mg/L2,4-D处理的温州蜜柑烂果率最低,保鲜效果最好。说明200mg/L2,4-D是处理柑橘的最佳浓度。 处理的温州蜜柑果皮中2,4-D含量在贮藏后12h和20d比残留限量高2.5%和6.3%;处理的罗岗甜橙果皮中2,4-D在贮藏20d之前含量基本都高于残留限量,20d以后低于残留限量,贮藏30d时比残留限量低13.9%。处理的温州蜜柑果肉中2,4-D含量低于残留限量;处理的罗岗甜橙果肉中2,4-D含量只有贮藏5d时比残留限量高31.5%,说明2,4-D处理的柑橘果肉安全性较高。更多还原

【Abstract】 In this thesis, study on 2,4-D residue in citrus( fruit coat, flesh), the activity of 2,4-dichlorophenol hydroxylase and the attribute change of citrus treated with 2,4-D were carried out. The purpose of the study was to realize residue and degradation of 2,4-D in citrus, to know whether the citrus was safe, and to improve fruits attribute with 2,4-D.Ministry of Agriculture China made the law that 2,4-D residue tolerance was 2mg/kg in citrus. The results showed that the content of 2,4-D was ranged from 28.5 ng/g to 8.1 ng/g in citrus from market, which showed that the citrus from market was safe.Mandarin fruits treated with 200mg/L, 100mg/L and 50mg/L 2,4-D, were detected residue of 2,4-D in citrus flesh after storage for 12 hours, 24 hours and 48 hours respectively. The results showed that residue of 2,4-D in flesh was from 50ng/g to 400ng/g, which less than residue tolerance. So the flesh was safe. The rate of bad-fruit of Mandarin fruits treated with 200mg/L 2,4-D was lowest. It showed that the best content of 2,4-D was 200mg/L.Mandarin fruit treated with 2,4-D, the content of it was 2.5% and 6.3% more than residue tolerance in fruits coat after storage for 12 hours and 20 days. Storage less than 20 days, the content of 2,4-D was more than residue tolerance in fruits coat of orange cv. luogan; it was less than residue tolerance when the orange stored more than 20 days. A month later, it was 13.9% less than residue tolerance. Compared with the control, the content of 2,4-D was less than residue tolerance in Mandarin flesh treated with 2,4-D; at the 5th day, the content of 2,4-D in flesh was 31.5% more than residue tolerance in orange cv. luogan treated with 2,4-D. It showed that thesafety of citrus flesh was high.The content of 2,4-D in fruit coat was higher than that in flesh, the content of 2,4-D in Mandarin fruits was less than that in orange cv. luogan.The content of 2,4-D in Mandarin fruits or orange cv. luogan decreased slowly (30 days). After 60 days of storage, the content of 2,4-D in Mandarin fruits or orange cv. luogan was lower which compared with the content after 30 days of storage. 2,4-D residue in fruit coat reached its maximum at the 20th day, 2,4-D residue in flesh reached its maximum at the 5th day. It showed that citrus absorbed 2,4-D gradually, in the same time, 2,4-D degraded gradually in the fruit.2,4-dichlorophenol hydroxylase is an enzyme during 2,4-D degradation. For 1-30 days of storage the activity of it was from 13.0x1000 U min-1.mg"1 Protein to 69.0x1000 U min-1mg"1 Protein.Treated with Sportak and 2,4-D could decrease the rate of bad-fruit in citrus, could inhibit decrease during storage.更多还原