作 者 ：张朋,王康才,赵杰,赵秀梅,郭庆海,陈志祥
期 刊 ：植物营养与肥料学报 2014年 20卷 6期 页码：1488-1496
Keywords:Chrysanthemum morifolium, NH+4-N /NO-3-N ratio, spot blight, secondary metabolism,
摘 要 ：【目的】 氮素形态与寄主营养和病害严重度的关系一直是人们关注的热点,氮素营养对植物次生代谢产物的影响也多有研究。斑枯病为杭白菊常见病害,黄酮和酚酸类物质是杭白菊主要的资源性化学成分。针对杭白菊生产中存在的问题,本文对不同铵硝比例处理下杭白菊的次生代谢及斑枯病发病情况进行调查和研究,以期为杭白菊生产过程中的氮素配施、 病害防治和次生代谢调控提供一定的技术借鉴。【方法】 采用盆栽试验,在总施氮水平相同的前提下,设置5个NH+4和NO-3比例,采用随机区组设计,管理措施一致,4次重复。采取对角线定点定株定期调查杭白菊斑枯病发病情况,采用描叶法和LI-3000C叶面积仪来确定植株病害状况,统计病情指数和病害发生率;测定苯丙氨酸解氨酶(PAL)、 木质素、 纤维素、 可溶性总糖、 可溶性蛋白、 超氧阴离子(O-2)、 丙二醛(MDA)等相关生理指标,超氧化物歧化酶(SOD)和过氧化物酶(POD)等抗氧化酶;测定不同处理下杭白菊花中次生代谢产物绿原酸、 木犀草苷、 3,5-O-双咖啡酰基奎宁酸以及根、 茎、 叶等不同部位总黄酮含量。对相关生理指标与发病率和病情指数进行相关性分析。【结果】 当铵硝比为25:75时木质素、 纤维素、 可溶性总糖、 POD、 苯丙氨酸和O-2含量达到最大值,MDA含量和SOD活性相对较低;杭白菊根、 茎、 叶及花中总黄酮的含量在铵硝比为25:75和0:100时均表现出较高的含量,绿原酸、 3,5-O-双咖啡酰基奎宁酸两者的含量在铵硝比为25:75时达到最大值,分别为0.67%和1.84%。随着硝态氮比例的增加杭白菊斑枯病的发病率和病情指数均有所下降。相关性分析显示木质素、 可溶性总糖、 PAL活性、 POD活性、 超氧阴离子、 绿原酸、 3,5-O-双咖啡酰基奎宁酸、 花中总黄酮的含量与杭白菊斑枯病的发病率和病情指数呈负相关,且达到极显著水平;SOD活性、 MDA含量与杭白菊斑枯病的发病率和病情指数呈正相关,且均达到显著水平。【结论】 杭白菊斑枯病的发病率和病情指数与相关生理指标和次生代谢密切相关,不同铵硝比例对药用菊花次生代谢产物及斑枯病的发生有一定的影响,当铵硝比为25:75时菊花斑枯病的发病率最低。
Abstract:【Objectives】Many researches have involved in the relationship between nitrogen forms and host nutrition and disease severity, and the effects of nitrogen nutrition on plant secondary metabolites. Spot blight is one of thecommon diseases of Chrysanthemum morifolium, and flavonoids and phenolic acids are the major chemicalingrediants of Chrysanthemum morifolium against the disease. In order to provide references for nitrogen fertilization with low disease and high level of secondary metabolism of Chrysanthemum morifolium in field production,effects of different ammonium to nitrate proportions on the secondary metabolism and physiological indicators relating to spot blight of Chrysanthemum morifolium were studied in this paper. 【Methods】 Pot experiments were carried out in greenhouse at the experimental station of Nanjing Agricultural University. At the base of same nitrogen level,five proportions of ammonium to nitrate nitrogen were designed with four replicates.Plants were chosen with diagonal lines for regular scheduled survey of spot blight incidence, andthe method of leaf description and LI-3000C leaf area meter were used to determine the level of plant diseases,disease index and disease incidence. The contents of lignin, cellulose, soluble sugar, soluble protein, the activities of superoxide radicals (O-2), malondialdehyde (MDA), superoxide dismutase (SOD) and peroxidase (POD) antioxidant enzymes were determined, and the secondary metabolites chlorogenic acid, luteolin, 3,5-O-double caffeoyl quinic acid in the flowers and total flavonoid content in different parts of Chrysanthemum morifolium were measured. 【Results】The contents of lignin, cellulose, total soluble sugar, POD, phenylalanine ammonia-lyase (PAL) and O-2 are all highest at the NH+4-N/NO-3-N ratio of 25:75, while the content of MDA and SOD activity are relatively lower. The total flavone content maintains a relatively higher level at the NH+4-N/NO-3-N ratio of 25:75-0:100, and the contents of chlorogenic acid and 3,5-O-dicoffeoylqunic acid are 0.67% and 1.84% respectively, reaching the maxima at the NH+4-N/NO-3-N ratio of 25:75. The incidence of spot blight and the disease index gradually drop with the increase of nitrate nitrogen proportion, and reachs the lowest level at the ratio of 25:75. The correlation analysis shows that lignin, total soluble sugars, the activity of PAL and POD, O-2, chlorogenic acid, 3,5-O-double-caffeoyl quinic acid and total flavonoids of flowers are negatively correlated with the spot blight incidence and disease index, reaching a significant level of 0.01, while the SOD activity and MDA content are positively correlated with the spot blight incidence and disease index, reaching a significant level of 0.05. 【Conclusions】 The results show that the spot blight incidence and disease index of Chrysanthemum morifolium are closely related to physiological indicators and secondary metabolites, and the spot blight and secondary metabolism of Chrysanthemum morifolium are significantly related to NH+4-N/NO-3-N ratio and reach the lowest level at the ratio of 25:75.
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