氯化胆碱对低温弱光下黄瓜幼苗叶片细胞膜和光合机构的保护作用

1.07mmol／L氯化胆碱处理降低了低温弱光（6℃．PFD100μmol m^-2s^-1）下黄瓜幼苗叶片膜脂组分中主要是磷脂酰甘油（PG）的饱和脂肪酸含量，增加了膜脂不饱和度：减缓了膜透性的下降、MDA的产生速率、叶绿素的降解及PSII最大量子效率（Fv/Fm）、捕光效率（Fv＇／Fm＇）、光化学猝灭系数（qp）、实际光化学效率（ФPSII）和抗氧化酶POD、APX及CAT活性的下降；提高了非光化学猝灭系数（NPQ）和脯氨酸的含量。以上结果表明氯化胆碱处理保护了低温弱光对黄瓜叶片细胞膜和光合机构的伤害。

Choline Chloride Protects Cell Membrane and the Photosynthetic Apparatus in Cucumber Seedling Leaves at Low Temperature and Weak Light

Choline chloride 1.07 mmol/L treatment diminished the saturated lipid contents of the fatty acid components mainly the phosphatidylglycerol (PG) resulting in the decrease of the saturation of lipid (Table 1), declined the permeability of cell membrane and the production of MDA from lipid peroxidation (Fig.2) in the cucumber seedling leaves under low temperature and weak light (6 degrees C, PFD 100 micromol m(-2) s(-1)). Furthermore, the choline chloride treatment alleviated the degradation of chlorophyll pigments especially chlorophyll b, the decrease in maximum photochemical efficiency (Fv/Fm), the capture efficiency of excited energy (Fv'/Fm'), the photochemical quenching coefficient (q(p)) and the actual photochemical efficiency (Phi PSII) of PSII (Table 2, Fig.3A, B & C), and decreases in activity of antioxidant enzymes such as POD, APX and CAT (Fig.4) in chilled leaves under weak light. In addition, choline chloride treatment increased the non-photochemical quenching (NPQ) (Fig.3D) and the proline content (Fig.5) in chilled leaves under weak light. The above results indicate that choline chloride protected the cell membrane and the photosynthetic apparatus in cucumber seedling leaves from chilling stress in weak light.