人工老化对大豆种子脂质及抗氧化系统的影响研究

发布时间：2018-05-03 01:40

本文选题：大豆 + 人工老化　；参考：《福建农林大学》2017年硕士论文

【摘要】：大豆含有丰富的脂质和蛋白,还具有含水量高、吸湿性等特点,在储藏过程中容易发生变质或者老化,影响大豆品质。前人实验发现老化导致大豆种子抗氧化酶活性降低,活性氧过量积累,MDA含量升高,表明老化伴随着脂质氧化损伤,但是并不清楚哪些脂质更容易受到老化影响;此外,老化处理引起的脂质过氧化作用,在种子吸胀萌发过程是会被修复还是加剧,亦不清楚。本文以人工老化"中豆27"大豆种子为实验材料,从脂质组学的角度分析老化对大豆种子的主要脂质和脂肪酸的影响,构建大豆的脂质图谱;然后从抗氧化系统角度,研究脂质变化与活性氧的联系,以进一步完善种子老化机理。获得的主要研究结果如下:1.大豆胚轴中脂质组成:大豆胚轴主要由脂肪酰类(Fatty acyls,FA)、甘油酯类(Glycerolipids,GL)、甘油磷脂类(Glycerophspholipids,GP)、鞘脂类(Sphingolipids,SP)、甾醇类(Sterol lipids,ST)、异戊烯醇脂类(Prenol lipids,PR)、糖脂类(Saccharolipids,SL)、聚酮类化合物(Polyketides,PK)8大类组成。其中GL的相对含量最高,约占大豆脂质总量的59.28%。大豆胚轴中甘油磷脂主要包括六类,分别是磷脂酰胆碱类(Phosphatidylcholime,PC)、磷脂酷乙醇胺类(Phosphatidyl-ethanolamine,PE)、磷脂酰丝氨酸类(Phosphatidyserine,PS)、磷脂酰肌醇类(Phosphatidylinositol,PI)、磷脂酸类(Phosphatidicacid,PA)和磷脂酰甘油类(Phosphatidylglycerol,PG)。其中PC含量最高,总量占磷脂总量的63%。大豆胚轴脂肪酸主要是由亚油酸、棕榈酸和硬脂酸组成,其中亚油酸为不饱和脂肪酸,含量约占脂肪酸总量的55%;棕榈酸和硬脂酸则为不饱和脂肪酸,含量分别约占脂肪酸总量的26.7%和 7.1%。2.老化处理对大豆胚轴脂质总量的影响很小,而对不同类别脂质的相对含量影响较为明显。主要体现在GL含量显著增加,相对于未老化的种子胚轴,随着发芽率的降低,其含量分别增加了 1.8%、3.3%和5.1%。而GP的含量却显著降低,相对于未老化的种子,发芽率为85%、46%和20%的种子分别降低了 5.8%、24.7和36%。老化导致脂肪酸含量显著降低。此外,老化导致不饱和指数显著降低。3.老化影响了细胞膜系统的完整性。PC是细胞膜脂的主要组分,总共有发现24种PC,其中溶血PC有9种。老化导致PC、PE、PA、PS和PI的含量显著降低,但PG的含量却随着发芽率的降低而显著上升,相对于未老化的种子,发芽率为85%、46%和20%的的种子中磷脂酰胆碱的含量分别降低了 5%、26.7%和38.2%。老化导致相对电导率上升,破坏了细胞膜结构,而且,发芽率越低,相对电导率越高。通过激光共聚焦显微镜,在老化胚轴中观察到细胞外膜荧光减弱,胞内荧光增强,表明老化破坏了细胞膜结构。老化导致MDA含量显著增加,相对于未老化的种子,发芽率为80%、46%和20%种子的种子分别增加了 27%、144%和152%,表明老化导致膜脂质发生过氧化作用。4.老化导致大豆胚轴活性氧的含量上升,同时还破坏了抗氧化系统,导致抗氧化剂及过氧化氢酶、抗坏血酸过氧化物酶和谷胱甘肽还原酶的活性降低,从而引起氧化还原平衡被破坏,加剧了活性氧的积累,导致过氧化伤害。5.吸胀可部分修复老化引起过氧化和脂质改变。与吸胀Oh的种子相比,吸胀24h种子的抗氧化酶的活性得到显著提高,表明吸胀24h可有效诱导胞内抗氧化系统活性,有效清除ROS;与吸胀Oh种子中相反,吸胀24h种子胚轴中PC、PE、PA、PS和PI的含量都是先降低而后增加,表明吸胀24h种子膜系统的脂质组成得到一定修复;此外,吸胀24h种子相对电导率都比吸胀Oh种子低,证明吸胀可部分修复老化引起过氧化和脂质改变。综上所述,老化处理削弱了大豆胚轴内的抗氧化系统,导致ROS大量积累。活性氧攻击脂质的不饱和键,导致细胞膜的主要组分PC、PE、PA、PS和PI的含量显著降低,同时也导致主要脂肪酸亚油酸、棕榈酸和硬脂酸的含量显著降低。从而破坏细胞膜功能与结构,引起种子活力下降。吸胀可能会激活胚轴中的抗氧化酶活性,从而部分修复老化所导致的过氧化及脂质的改变。在老化前期,修复作用比较小,在老化后期,发芽率越低,老化处理对脂质的影响以及吸胀对该作用的修复效果越显著。
[Abstract]:Soybean is rich in lipid and protein, and has the characteristics of high moisture content and hygroscopicity. It is easy to deteriorate or aging during storage, which affects soybean quality. Previous experiments have found that aging leads to the decrease of antioxidant enzyme activity, excessive accumulation of active oxygen and the increase of MDA content, indicating that aging is accompanied by lipid oxidative damage. It is not clear which lipid is more susceptible to aging; in addition, it is not clear whether the lipid peroxidation caused by aging treatment will be repaired or intensified during seed expansion and germination. In this paper, the artificial aging "Zhong bean 27" soybean seed was used as the experimental material to analyze the main lipid of aging soybean seeds from the angle of liposome. The lipid profile of the soybean was constructed and the relationship between the lipid changes and reactive oxygen species was studied from the angle of antioxidant system to further improve the mechanism of seed aging. The main results obtained are as follows: 1. the lipid composition in Soybean Hypocotyls: the soybean hypocotyls are mainly fatty acyl (Fatty acyls, FA), glycerol esters (Glycerolipids, GL). Glycerophspholipids (GP), Sphingolipids (SP), sterols (Sterol lipids, ST), isoamyl alcohol lipids (Prenol lipids, PR), glycolipid (Saccharolipids, SL) and polyketones, which have the highest relative content, which account for glycerin and phosphorus in soybean hypocotyls. Lipids mainly include six types: phosphatidylcholine (Phosphatidylcholime, PC), phosphatidyl ethanolamine (Phosphatidyl-ethanolamine, PE), phosphatidyl serine (Phosphatidyserine, PS), phosphatidylinositol (Phosphatidylinositol, PI), phosphatidic acid (Phosphatidicacid, PA) and phosphatidyl glycerol (Phosphatidylglycerol, PG). The 63%. soybean hypocotyl fatty acids with the highest PC content and total amount of phospholipid are mainly composed of linoleic acid, palmitic acid and stearic acid, in which linoleic acid is unsaturated fatty acid, the content is about 55% of the total fatty acid, and palmitic acid and stearic acid are unsaturated fatty acids, and the content is about 26.7% and 7.1%.2. aging treatment of fatty acids. The influence of the total amount of lipid on the soybean hypocotyl was small, but the relative content of different kinds of lipids was more obvious. It was mainly reflected in the increase of GL content. Compared with the immature seed hypocotyl, the content of GP increased with the decrease of germination rate, but the content of GP decreased significantly, compared with the immature seeds. The germination rate of 85%, 46% and 20% decreased by 5.8%, 24.7 and 36%., which led to a significant decrease in fatty acid content. In addition, aging leads to a significant reduction in the.3. aging effect on the integrity of the cell membrane system.PC is the main component of the cell membrane lipid, and a total of 24 kinds of PC are found, including 9 kinds of hemolytic PC. Aging leads to PC, PE, PA, PS and The content of PI decreased significantly, but the content of PG increased significantly with the decrease of germination rate. The content of phosphatidylcholine in the seeds of 85%, 46% and 20% decreased by 5% compared with those of the non aged seeds, and the relative electrical conductivity increased by 26.7% and 38.2%. aging, breaking the cell membrane structure, and the lower the germination rate, the relative electricity was relatively low. The higher the conductivity was, the fluorescence of the outer membrane was weakened and the intracellular fluorescence was enhanced by laser confocal microscopy, indicating that aging destroyed the cell membrane structure. Aging resulted in a significant increase in MDA content. The germination rate was 80%, 46% and 20% seeds were increased by 27%, 144% and 152%, respectively, compared with those of the immature seeds. The oxidative effect of membrane lipid peroxidation caused.4. aging to increase the content of active oxygen in soybean hypocotyls, and also destroyed the antioxidant system, which resulted in the reduction of antioxidants and catalase, the activity of ascorbic acid peroxidase and glutathione reductase, which resulted in the oxidation of the original balance and the accumulation of active oxygen. The oxidative damage caused by peroxidation can partially repair oxidation and lipid changes caused by aging. Compared with the seeds of the bloated Oh, the activity of antioxidant enzymes of the expanded 24h seeds is significantly improved, which indicates that the swelling 24h can effectively induce the activity of the intracellular antioxidant system and effectively clear the ROS, contrary to the Oh seeds of the bloated 24h seed, PC, PE, PA, P in the embryo axis of the 24h seed. The content of S and PI decreased first and then increased, indicating that the lipid composition of the bloated 24h seed membrane system was repaired. In addition, the relative conductivity of the imbibed 24h seed was lower than that of the bloated Oh seed, which proved that the swelling could partly repair the oxidation and lipid changes in the aging process. In conclusion, the aging treatment weakened the antioxidant system in the soybean hypocotyl. It leads to a large accumulation of ROS. The unsaturated bonds of reactive oxygen species attack lipids lead to a significant reduction in the content of the main components of the cell membrane, such as PC, PE, PA, PS and PI, and a significant decrease in the content of the main fatty acids, palmitic acid and stearic acid, which may destroy the function and structure of the cell membrane and cause the decrease of seed vigor. The activity of antioxidant enzymes in the axis, thus partially repairing the peroxide and lipid changes caused by aging. In the early age of aging, the repair effect is smaller. In the late aging, the lower the germination rate, the effect of aging treatment on the lipid and the more significant effect of the healing of the effect.

【学位授予单位】：福建农林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S565.1

【参考文献】