氮素形态对藿香光合作用、氮代谢及品质的影响

[目的] 研究不同氮素形态及配比对藿香光合特性、氮代谢相关酶活性及品质的影响,为藿香氮肥合理施用提供依据。[方法] 以蛭石为栽培基质,藿香为试验材料,采用不同铵态氮、硝态氮比例处理,分析不同铵硝比处理下藿香的光合特性、氮素代谢相关酶[硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸合酶(GOGAT)]活性、生物量及主要化学成分的变化。[结果] 藿香光合色素含量随着铵硝比的增大呈先升后降的趋势,当NH4+-N/NO3--N为25:75(质量比,下同)时,叶片中光合色素含量、净光合速率(Pn)均最高,且主要化学成分胡薄荷酮及长叶薄荷酮的相对含量均最高。在全NH4+-N处理下,叶片中叶绿素a、类胡萝卜素含量均最低,而主要化学成分D-柠檬烯及胡椒酚甲醚的相对含量最高;NH4+-N/NO3--N为75:25时,叶片中GS、GOGAT、NR活性及其不同部位铵态氮含量均达到最大值;NH4+-N/NO3--N为50:50时,茎中硝态氮、铵态氮含量均最低。随着NO3--N比例的增加,单株干质量、鲜质量以及叶片中可溶性总糖的含量均呈先升后降的趋势,并在NH4+-N/NO3--N为25:75时,总黄酮、挥发油含量均最高。[结论] 当NH4+-N/NO3--N为25:75时,对藿香的光合特性、生物量及主要化学成分的影响较其他铵硝配比显著,并能更加有效地促进藿香的净光合速率,提高挥发油含量,其促进效果也比单一形态氮素营养更为显著。
[Objectives] We studied effects of nitrogen form on photosynthetic characteristics,the activity of nitrogen metabolism-related enzymes and quality of Agastache rugosa,in order to provide the theoretical basis for nitrition regulation of A.rugosa.[Methods] By using vermiculite as growing media and A.rugosa as the experimental material,we analyzed the photosynthetic characteristics,active of nitrogen metabolism-related enzymes(NR,GS,GOGAT),biomass and main chemical component of A.rugosa under different NH4+-N/NO3--N ratio treatments.[Results] The content of photosynthetic pigment in the leaves of A.rugosa with the NH4+-N/NO3--N ratio increasing,increased firstly and then decreased. When the NH4+-N/NO3--N ratio was 25:75,the content of photosynthetic pigment,photosynthesis rate was the highest,meanwhile,the relative contents of main chemical component of menthone and pulegone followed the same trends. When the NH4+-N/NO3--N ratio was 100:0,the content of chlorophyll(a),carotenoid of A.rugosa in leaves were the lowest,but,the relative content of main chemical component of D-limonene and methylchayicol were the highest. The activities of GS,GOGAT,and NR in leaves of A.rugosa were the highest at the NH4+-N/NO3--N ratio of 75:25,so was the content of ammonium nitrogen in different parts of A.rugosa. When the NH4+-N/NO3--N ratio was 50:50,the content of nitrate nitrogen and ammonium nitrogen in stem of A.rugosa were the lowest. With the NH4+-N/NO3--N ratio increasing,the single-plant dry weight and wet weight and the content of soluble sugar in leaves of A.rugosa increased firstly and then decreased. And,when the NH4+-N/NO3--N ratio was 25:75,both the content of total flavonoids and oil of A.rugosa were the highest.[Conclusions] The characteristics of photosynthetic,biomass and main chemical component of A.rugosa were significantly influenced by NH4+-N/NO3--N ratio which goes to 25:75. Meanwhile,it could promote the photosynthesis rate more