The Effect Of KH₂PO₄on The Cold Resistance Characteristics Of Qinghuajiao

Qinghuajiao is one of trees belonging to Rrutaceae ZanthoxylumL., whose scientific name is Z.armatum DC Prodr. As a kind of characteristic resource in Sichuan, it has a main feature of fragrance which plays a significant role in preventing pest and inhibiting bacterial. In recent years, cultivation area of Qinghuajiao has been increasing continuously. When it is brought to the north or high altitudes, low temperature becomes an essential factor to limit the introduction, cultivation and industrial development of Qinghuajiao. This article took Zanthoxylum.armatum’Teng’one-year-old seedlings as experiment materials to study Qinghuajiao’s cold resistance characteristics in Sichuan agricultural university’s farm. Temperature condition:6℃,3℃,0℃,-3℃and-6℃.Time:24h.Spraying titer:water,0.2%KH2PO4,0.4%KH2PO4,0.6%KH2PO4and0.8%KH2PO4. LT50,SOD activity and other physiological and biochemical processes has been studied in these experiments. And adopting the method of main component analyses to explore the cold resistance characteristics which is useful for rational planting, cold resistance breeding, appraising and popularizing Qinghuajiao.The main results are follow:(1)<3℃,24h, leaves of Qinghuajiao seedlings began to turn wilting. Dealt with6℃,3℃and0℃,all of Qinghuajiao seedlings recovered. About66%of seedlings spraying0.6%KH2PO4and dealt with-3℃were vegetative and others were died after20days at normal temperature.(2) LT50of Qinghuajiao seedlings spraying water were1.33℃and after spraying0.2%,0.4%and0.6%KH2PO4, the LT50respectively were-0.86℃,-0.99℃and0.77℃,all lower than CK. So a low concentration of KH2PO4can reduce the seedlings’ LT50.(3) Spraying KH2PO4can lower the Qinghuajiao’s Pro content and MDA content simultaneously, heighten their soluble sugar content, soluble protein content, SOD activity and POD activity. But there was no significant difference in CAT activity.Through main component analyses, the evaluation of the cold resistance of Qinghuajiao seedlings become more integrated and the conclusion is that Qinghuajiao’s cold resistance is weaker than Zanthoxylum bungeanum and spraying KH2PO4can heighten its cold resistance characteristics.