2种紫花苜蓿氮代谢及其关键酶(NR、GS)活性差异研究

Nitrogen metabolism and nitrogen metabolism enzymes(NR,GS) activity in two alfalfa cultivars

摘要:

为探究不同紫花苜蓿氮代谢差异及氮代谢差异的生理机制,采用盆栽砂培法,通过对2个具有典型特征的紫花苜蓿品种(LW6010和陇东苜蓿)在2个氮素水平及3个生育时期下其氮代谢产物及氮代谢酶活性差异进行研究,探讨氮代谢产物与氮代谢酶活性的相互关系。结果表明:LW6010和陇东苜蓿在N210水平下其干物质重、氮含量、氮积累量及硝酸还原酶(NR)、谷氨酰胺合成酶(GS)活性均高于N21。在2个氮水平下,LW6010的干物质重、NR和GS活性均显著大于陇东苜蓿,而LW6010的氮含量显著低于陇东苜蓿。其中,LW6010的NR活性比陇东苜蓿在N210和N21下分别高24%和15%(苗期)、31%和40%(现蕾期)、20%和11%(盛花期);GS活性分别高30%和29%(苗期)、33%和20%(现蕾期)、7%和14%(盛花期)。在苗期和盛花期时,LW6010的氮积累量显著大于陇东苜蓿,而在现蕾期差异不显著。LW6010的氮积累量在N210下各生育期分别比陇东苜蓿高25%,3%和16%,而在N21下LW6010的氮积累量在苗期和盛花期下比陇东苜蓿高45%和12%。同时,紫花苜蓿干物质重、氮积累量、NR活性与GS活性呈极显著正相关关系。综上分析,紫花苜蓿的不同品种在不同氮素水平下其氮代谢能力不同,不同紫花苜蓿品种间氮代谢具有差异;LW6010较陇东苜蓿具有较好的氮代谢能力;NR和GS活性可为不同紫花苜蓿氮代谢差异评价提供参考。

Abstract:

In order to identify the mechanism of nitrogen metabolism in different alfalfa cultivars (LW6010 and Longdong),nutrition sand culture experiment was used to study the changes of nitrogen metabolism and nitrogen metabolism enzymes activity under two nitrogen levels at three growth periods.In addition,the relationship between nitrogen metabolism and nitrogen metabolism enzyme activity was also examined.The results showed that dry matter,nitrogen content,nitrogen accumulation,NR and GS activities of alfalfa under N210 were higher than those under N21.Dry matter,NR and GS activity of LW6010 were significantly higher than those of Longdong;however,nitrogen content of LW6010 was significantly lower than that of Longdong.NR activities of LW6010 under N210 and N21 were increased by 24% and 15% (seedling stage),31% and 40% (budding stage),20% and 11% (flowering stage) compared with Longdong.Similarly,GS activities of LW6010 under N210 and N21 were increased by 30% and 29% (seedling stage),33% and 20% (budding stage),7% and 14% (flowering stage) compared with Longdong.Nitrogen accumulation of LW6010 was significantly higher than that with Longdong at seedling stage and flowering stage.Nitrogen accumulation of LW6010 under N210 was increased by 25%,3% and 16% at three growth stages.Nitrogen accumulation of LW6010 under N21 was increased by 45% and 12% at seedling stage and flowering stage.At the same time,there was a significant positive correlation between dry weight,nitrogen accumulation,NR activity and GS activity of alfalfa.In general,different alfalfa cultivars have different nitrogen metabolism capacity under different nitrogen levels.LW6010 has higher nitrogen metabolism capacity than Longdong.NR and GS activities can be used as evaluation parameters to evaluate differences in nitrogen metabolism of alfalfa,which can provide a reference for further breeding of alfalfa cultivars with high nitrogen metabolism.