水保所知识产出(1956---)知识库

小麦产量主要来自于小麦灌浆期旗叶的光合产物, 低氮造成的灌浆期旗叶早衰对小麦产量影响极大。本试
验以小麦品种“长旱 58”为试验材料, 在大田环境下设置低氮(120 kg hm 2 )和正常氮(180 kg hm 2 )处理, 研究低氮诱导
的小麦旗叶衰老与膜脂的关系。结果表明, 开花 14 d 后, 低氮处理小麦旗叶的光合速率、叶绿素含量、旗叶总氮含
量均显著降低; 旗叶中膜脂各组分含量均显著下降, DGDG/MGDG 的比值升高; 以 C18:3、C18:2 为代表的不饱和脂
肪酸含量显著下降, 以C16:0为代表的饱和脂肪酸含量显著增加, 不饱和双键指数显著降低; 此外类囊体蛋白质堆积
密度也显著降低。综合分析认为低氮处理导致小麦灌浆期旗叶早衰, 早衰过程伴随着膜脂降解和组分改变, 降低了膜
的流动性和通透性, 导致叶绿素降解, 使光合功能受损。同时, 植物通过调整 DGDG/MGDG 比例来响应低氮胁迫, 利
用 DGDG 的双层特性来部分弥补其它双层膜脂的降解对膜功能造成的损伤。

Nitrogen (N) deficiency induces flag leaf senescence at the grain-filling stage of wheat resulting in yield decrease. In
this study, we carried out a field experiment to investigate the relationship between N-deficiency-induced flag leaf senescence and
lipid change using wheat variety ‘Changhan 58’. Under the low-N (120 kg ha –1 ) condition, the photosynthetic rate, chlorophyll
content, total N content, and contents of all lipid components of flag leaf at 14 days after flowering were significantly lower than
those under normal-N (180 kg ha –1 ) condition, while the DGDG/MGDG ratio in low-N treatment increased. The content of un-
saturated fatty acids, such as C18:3 and C18:2 decreased significantly, whereas the contents of saturated fatty acids, such as C16:0,
increased significantly, leading to the reduction of index of unsaturated double bounds. In addition, thylakoid protein packing
density also decreased under N-deficiency condition. These results indicate that N-deficiency-induced leaf senescence is charac-
terized with lipid degradation and components changes, which result in negative effects on reductions of membrane permeability,
chlorophyll content and photosynthetic rate. Simultaneously, the DGDG/MGDG ratio of plants is adjusted in response to N defi-
ciency to alleviate damages of membrane function caused bby lipid degradation.