水培条件下氮素对拟巫山淫羊藿产量和黄酮类成分的影响

Effects of nitrogen on yields and flavonoids contents of Epimedium pseudowushanense in hydroponic conditions

采用水培方法研究了不同氮浓度和氮素形态及配比对拟巫山淫羊藿产量和黄酮类成分的影响。氮浓度设7个处理组N0~N6,分别为0,2.5,5.0,7.5,10.0,13.0 mmol·L^(-1);氮形态设5个处理组T1~T5,硝铵比NO3-N/NH4-N依次为5∶0,4∶1,2.5∶2.5,1∶4,0∶5,总施氮量为5 mmol·L^(-1)。结果表明,随氮浓度的增大,拟巫山淫羊藿的生物量和叶干重均显著升高,N5组的生物量和叶干重分别比N0组和N4组高29%,23%和36%,23%(P<0.05),但与N6组差别不显著;根,茎干重变化不明显。净光合速率及各光合色素含量在N3~N5组中较高。朝藿定A,B,C,淫羊藿苷及总黄酮含量在N3组最低,N4组突然升高,N4~N6组变化不大,朝藿定C的含量最高的N5组比含量最低的N3组高131%(P<0.05)。在不同硝铵比处理组中,生物量,单株叶干重,茎干重在硝铵比为2.5∶2.5时最大,单纯施用硝态氮(T1)和铵态氮处理(T5)最低(二者差异不显著);各光合色素含量和净光合速率在T3和T4组最低,其他3组较高。氮形态对黄酮含量的影响远小于氮浓度的影响。朝藿定C的含量在T1组中最高,但仅比T2~T5组高5%~8%(P<0.05),其他4组间差异不明显。朝藿定A,B,淫羊藿苷及总黄酮含量在T1组中均较高,在T2组中最低,T1组分别比T2组高41%,62%,27%(P<0.05)。拟巫山淫羊藿为高氮耐受性植物,10.0 mmol·L^(-1)是其生长转向良好的拐点,最适的氮浓度为10.0~13.0 mmol·L^(-1),喜好硝态氮和铵态氮混施,最适的氮形态及配比为2.5 mmol·L^(-1)硝态氮+2.5 mmol·L^(-1)铵态氮。

Nitrogen nutrition divided into concentrations and forms for Epimedium pseudowuhanense was studied under hydroponic conditions. There were 7 nitrogen concentrations treatments （N0-N6） which nitrogen concentration was 0, 2.5, 5.0, 7. 5, 10. 0, 13.0 mmol·L-1 , respectively, and 5 nitrogen forms and proportions treatments （T1-T5） which NO3-N/NH4-N was 5： 0, 4： 1, 2. 5： 2.5, 1 ： 4, 0：5 respectively, the total nitrogen applied was 5 mmol · L- 1. The results showed that along with the increase of nitrogen concen- tration, biomass （dry weight） and leaf dry weight increased, which in N5 treatment was 29%, 23% higher than those in NO and36%, 23% higher than those in N4 respectively, but not significantly different from N6 treatment. Roots and stem dry weights did not change significantly. Pn and the contents of photosynthetic pigments were higher in N3-N5 treatments. Epimedin A, B, C, ieariin and total flavonoids contents were the lowest in N3 treatment, suddenly increase in N4 treatment and only a little change between N4-N6 treatments. N5 treatment with the highest epimedin C content was 131% higher than N3 treatment with the lowest epimedin C content （ P 〈 0.05 ）. While in the nitrogen forms and proportions treatments, biomass, leaf and stem dry weights were the highest in 3＂3 treat- ment and lower in T1 and 3＂5 treatments, without significance between T1 and T5 treatments. These indicators in T3 treatment were more than 30% higher than those in T1 treatment. The impact of nitrogen concentrations was greater than nitrogen forms on flavonoids. epmedin C content was the highest in T1 treatment, only 5% -8% higher than that in T2-T5 treatments （ no significance between 4 treatments）. Epimedin A, B, icariin and total flavonoids contents were higher in T1 treatment, the lowest in T2 treatment, those in T1 treatment was 41%, 62% and 27% higher than I2 treatment respectively （P 〈0. 05）. In a conclusion, E. pseudowushanense is a high nitrogen tolerant plant, 10. 0 mmol · L-1 was the boundary point between growing general to well and the optimal nitrogen concen- tration for it was 10. 0-13. 0 mmol · L-1. Besides, it prefers to grow in NO3 plus NH4＋ and the optimal proportion was 2. 5： 2. 5.