施氮对闽楠挥发性次生代谢物组分和含量的影响

Effects of nitrogen application on components and contents of volatile secondary metabolites in Phoebe bournei

【目的】探讨不同施氮量对闽楠枝叶挥发性次生代谢物的组分和含量的影响,提高闽楠的开发利用价值。【方法】以湖南省永州市金洞林场10年生闽楠人工林为试验林,分别按照每株施氮量(46%的尿素)0、100、200、300、400 g进行处理,在施肥前、施肥后6个月、施肥后12个月进行采样,采用水蒸馏萃取法提取闽楠枝叶挥发性次生代谢物,采用气质联用法分析闽楠枝叶挥发性次生代谢物成分。【结果】5个施肥处理检测出相对含量在1%以上的叶挥发性次生代谢物共有78种,其中烃类51种,醇类16种,醛类7种,酯类2种,萘类2种;枝挥发性次生代谢物共有84种,其中烃类54种,醇类21种,醛类6种,酯类2种,萘类1种。其中枝和叶挥发性次生代谢物相同的成分有48种,主要成分都以萜烯烃类为主,但有一定差异,叶的挥发性次生代谢物的典型成分为白菖烯、杜松萜烯、大根香叶烯、香树烯、石竹烯、γ-衣兰油烯、古巴烯等,枝挥发性次生代谢物的典型成分为古巴烯、杜松萜烯、石竹烯、(-)-Alpha-荜澄茄油烯、γ-衣兰油烯、α-石竹烯等。施氮量和施氮时间的变化会影响闽楠枝叶挥发性次生代谢物主要成分的相对含量,施肥后6个月至12个月的闽楠叶挥发性次生代谢物含量略微降低,枝挥发性次生代谢物含量小幅增加,且施氮肥为200 g/株时,枝挥发性次生代谢物含量达到最高,施400 g/株氮肥时,叶挥发性次生代谢物含量达到最高。施肥6个月后的枝叶挥发性次生代谢物含氧化合物相对含量均高于施肥前和施肥1 a后。【结论】闽楠枝叶挥发性次生代谢物的含量和施肥时间、施肥量有一定的关系,施肥能显著提高枝次生代谢物的含量,对叶挥发性次生代谢物的含量影响不大,但是施肥可以改变其主要挥发性次生代谢物的相对含量并降低含氧化合物的含量,从而降低挥发性次生代谢物的香气与抗菌性。因此,可通过对闽楠的不同氮肥施肥梯度的处理来调控特定成分的含量,从而对闽楠进行定向培育与产品开发。

【Objective】The aim was to explore the effects of different nitrogen application rates on the components and contents of volatile secondary metabolites in branches and leaves of Phoebe bournei,so as to improve the development and utilization value of Phoebe bournei.【Method】Taking the 10-year-old Phoebe bournei plantation in Jindong Forest Farm of Yongzhou City,Hunan Province as the experimental forest,5 urea(with a concentration of 46%)treatments were carried out with a nitrogen content of 0 g,100 g,200 g,300 g and 400 g per plant,respectively.The samples were collected before fertilization,6 months after fertilization and 12 months after fertilization.The volatile secondary metabolites of Phoebe bournei branches and leaves were extracted by water distillation extraction,which were then analyzed by GC-MS.【Result】Among the detected volatile compounds with a relative content above 1%in the 5 treatments,there were 78 kinds of volatile compounds in leaves,including 51 hydrocarbons,16 alcohols,7 aldehydes,2 esters and 2 naphthalenes.There were 84 kinds of volatile substances in branches,including 54 kinds of hydrocarbons,21 kinds of alcohols,6 kinds of aldehydes,2 kinds of esters and 1 kind of naphthalene.There were 48 kinds of volatile secondary metabolites in branches and leaves,and the main components were terpenes,but there were some differences.The typical components of volatile secondary metabolites in leaves were alloaromadendrene,(+)-δ-cadinene,(+)-germacrene-D,(−)-allo-Aromadendrene,Caryophyllene,γ-muurolene,Copaene,etc.The typical components of branch volatile secondary metabolites were Copaene,(+)-δ-cadinene,Caryophyllene,(-)-alpha-Cubebene,γ-muurolene,α-Caryophyllene,etc.The changes of nitrogen application rate and nitrogen application time could affect the relative contents of the main volatile secondary metabolites in branches and leaves of Phoebe bournei.The content of volatile secondary metabolites in Phoebe bournei leaves decreased slightly from 6 months to 12 months after fertilization,and the content of volatile secondary metabolites in branches increased slightly.When the nitrogen fertilizer was 200 g/plant,the content of volatile secondary metabolites in branches reached the highest.When the concentration of nitrogen fertilizer was 400 g/plant,the content of volatile secondary metabolites in leaves reached the highest.The relative contents of volatile secondary metabolites of branches and leaves in the 6th month after fertilization were higher than those before fertilization and after 1-year fertilization.【Conclusion】The content of volatile secondary metabolites in branches and leaves of Phoebe bournei has a certain relationship with fertilization time and the fertilization amount.Fertilization can significantly increase the content of secondary metabolites in branches,but has little effect on the content of volatile secondary metabolites in leaves.However,fertilization can change the relative content of the main volatile secondary metabolites and reduce the content of oxygen-containing compounds,thereby reducing the aroma and antibacterial properties of volatile secondary metabolites.Therefore,the content of specific components can be regulated through the treatment of different nitrogen fertilization gradients on Phoebe bournei,so as to carry out targeted cultivation and product development.