小麦苗期叶片膜脂组成对低氮胁迫的响应及其与耐低氮的关系

Effect of nitrogen deficiency on leaf lipid composition in different nitrogen-deficiency tolerant wheat (Triticum aestivum) cultivars during seedling stage

本研究以‘濮麦9号’和‘宁麦14号’为试验材料,探究低氮胁迫对小麦(Triticum aestivum)苗期中下部叶片膜脂组成的影响。结果表明低氮处理后‘濮麦9号’生物量下降幅度明显低于‘宁麦14号’,胁迫后‘濮麦9号’的叶绿素含量、光系统Ⅱ(PSII)最大光化学效率和光合速率都显著高于‘宁麦14号’。低氮胁迫下,两个小麦品种叶片中的单半乳糖甘油二酯(monogalactosyldiacylglycerol,MGDG)、双半乳糖甘油二酯(digalactosyldiacylglycerol,DGDG)及总脂含量都显著降低,但‘濮麦9号’叶片中的总脂、DGDG含量、DGDG/MGDG比值以及MGDG、磷脂(phospholipid,PL)和总脂的不饱和脂肪酸双键指数(DBI)都显著高于‘宁麦14号’。由此可见,低氮胁迫后小麦叶片膜脂组分及含量的不同变化可能是这两个小麦品种对低氮胁迫响应不同的重要原因之一。

The objective of this study was to evaluate the effect of nitrogen deficiency on membrane lipid composition and contents in different nitrogen-deficiency tolerant wheat（Triticum aestivum） cultivars. Two wheat cultivars（‘Pumai 9＇, PM9; ‘Ningmai 14＇, NM14） were grown in nitrogen-deficiency hydroponic solution for one month. The results show that the biomass was more decreased in NM14 than PM9 under nitrogen-depleted condition. The chlorophyll content, photochemical efficiency of photosystem II（PSII） and photosynthetic rate in PM9 were significantly higher than those of NM14 during nitrogen deficiency. Lipid analyses showed that the levels of monogalactosyldiacylglycerol（MGDG）, digalactosyldiacylglycerol（DGDG） and total lipid in the two cultivars were decreased under nitrogen-depleted condition. However, the contents of DGDG, DGDG/MGDG and total lipid of PM9, the double bond index（DBI） in MGDG, phospholipid（PL） and total lipid in PM9 were significantly higher than those of NM14 after nitrogen-deficiency treatment. Taken together, the changes of lipid components and contents in leaves might play an important role in the response to nitrogen-depleted condition.