氮素形态对藿香光合作用、氮代谢及品质的影响

Effects of nitrogen form on photosynthesis,nitrogen metabolism and quality of Agastache rugosa

[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NH^+_4-N/NO^-_3-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NH^+_4-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;NH^+_4-N/NO^-_3-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;NH^+_4-N/NO^-_3-N为50∶50时,茎中硝态氮、铵态氮含量均最低。随着NO^-_3-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NH^+_4-N/NO^-_3-N为25∶75时,总黄酮、挥发油含量均最高。[结论]当NH^+_4-N/NO^-_3-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 effectively and increace the content of oil of A.rugosa. Besides,the promoting effect was more noticeable than the single nitrogen form nutrition.