渗透调节对冷敏感大豆[Glycine max(L.)Merr.]种子膜类脂组成和脂肪酸含量的影响

选用冷敏感的大豆[Gzycine max（L.）Merr．]品种“中黄22”为试材,运用薄层层析法和气相色谱法研究了渗控增强大豆种子活力过程中膜类脂的组成及变化规律,揭示生物膜类脂在抗吸胀冷害中的作用。结果表明,用33％（W／V）的PEG6000处理种子,随着渗控时间的延长,种子的发芽指数、活力指数和根干重都逐渐增加,在渗控72h时,大豆种子中不饱和磷脂如PC、PE的比例增加,各极性脂的脂肪酸组成也发生了变化,PC、PE和PI中饱和脂肪酸16：0的含量显著下降,而不饱和脂肪酸18：2明显上升,使它们的不饱和指数大大提高,并与渗控时间呈正相关。由以上结果可证明,经PEG渗控处理后,提高了冷敏感大豆膜的流动性,为防止吸胀冷害,保持膜系统的完整性和生物膜正常的代谢提供了前提条件。     

Seed priming effects on growth,lipid peroxidation,and activity of ROS scavenging enzymes in NaCl-stressed sorghum seedlings from aged seeds

Abstract

The aim of this study was to evaluate growth, lipid peroxidation, and activity of antioxidative enzymes in sorghum seedlings grown under salt stress from artificially aged and primed seeds. The experimental design was completely randomized, with four replications per treatment, in a 2×2×2 factorial arrangement that consisted of eight treatments: two seed vigor levels (aged or not), two seed types (primed or not), and two salinity levels (0 and 100 mM NaCl). In low physiological quality (aged) seeds, the osmoconditioning mitigated the salinity negative effects (NaCl at 100 mM) on seedling growth. The results suggest that osmoconditioning induced an increase in catalase (CAT) and guaiacol peroxidase (POX) activities and these enzymes protected the seedlings against oxidative damage caused by seed accelerated aging and salinity in nutrient solutions. Finally, the observed behavior for superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities suggest that changes in these enzymes in both shoot and roots could do not be induced by studied treatments, because the changes in these organs are unrelated to each other.     

渗透调节增强大豆种子活力

选用对吸胀冷害敏感的大豆 [Glycine max(L.)Merr.]品种‘黑河23‘为试材,系统研究了渗控增强种子活力的机理.结果表明,与对照相比,渗控12 h显著提高种子抗吸胀冷害的能力,并且随着渗控时间的延长逐渐增强,表现在种子渗漏物减少,渗漏物中K /Na 比降低,冷浸对活力指数的负效应减小.水苏糖、蔗糖的含量在12 h达最大值,以后呈缓慢下降趋势,而葡萄糖、果糖含量在渗控后期开始上升.过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)、谷胱甘肽还原酶(GR)等抗氧化酶的活性在整个渗控过程中都有不同程度的增强,丙二醛(MDA)含量减少.表明渗控可提供一个合适的渗透压,使种子在适度的渗透压下启动萌发过程.研究还揭示22℃渗控效果优于4℃.     

Osmopriming-Regulated Changes of Plasma Membrane Composition and Function were Inhibited by Phenylarsine Oxide in Soybean Seeds

The aim of the present work was to investigate the effects of osmoconditioning on chilling injury in chilling-sensitive soybean （Glycine max （L.） Merr. Zhonghuang No. 22） seeds during imbibition. Low temperatures reduced the germination rate and no seed germinated at 1 ℃. Osmoconditioning of seeds at 20℃ with a polyethylene glycol-8000 （PEG8000） solution at 1.5 MPa for 72 h followed by drying back to their initial moisture content （MC） reduced their chilling sensitivity. The phenylarsine oxide （PAO）, an inhibitor of protein tyrosinephosphatases, was used to investigate the possible involvement of phosphorylation-dephosphorylation of Tyr residues in the plasma membrane composition and function when seeds were osmoconditioned. The results showed the germination of osmoconditioned seeds decreased significantly when PAO was added in PEG solution after chilling treatment. PAO inhibited changes in composition of plasma membrane phospholipids and fatty acid induced by osmocondition, indicated that tyrosine protein phosphorylation is involved in the regulatory mechanisms of osmocondition-responsive chilling in soybean seeds. Western blot result further indicated that osmocondition treatment improved the activity of plasma membrane H^＋-ATPase after chilling treatment, but this effect was abolished by PAO. The possible regulation mechanism by Tyr protein phosphorylation is discussed.     

Osmopriming-Regulated Changes of Plasma Membrane Composition and Function were Inhibited by Phenylarsine Oxide in Soybean Seeds

The aim of the present work was to investigate the effects of osmoconditioning on chilling injury in chilling-sensitive soybean ( Glycine max (L.) Merr. Zhonghuang No. 22) seeds during imbibition. Low temperatures reduced the germination rate and no seed germinated at 1 °C. Osmoconditioning of seeds at 20 °C with a polyethylene glycol-8000 (PEG8000) solution at 1.5 MPa for 72 h followed by drying back to their initial moisture content (MC) reduced their chilling sensitivity. The phenylarsine oxide (PAO), an inhibitor of protein tyrosinephosphatases, was used to investigate the possible involvement of phosphorylation-dephosphorylation of Tyr residues in the plasma membrane composition and function when seeds were osmoconditioned. The results showed the germination of osmoconditioned seeds decreased significantly when PAO was added in PEG solution after chilling treatment. PAO inhibited changes in composition of plasma membrane phospholipids and fatty acid induced by osmocondition, indicated that tyrosine protein phosphorylation is involved in the regulatory mechanisms of osmocondition-responsive chilling in soybean seeds. Western blot result further indicated that osmocondition treatment improved the activity of plasma membrane H⁺-ATPase after chilling treatment, but this effect was abolished by PAO. The possible regulation mechanism by Tyr protein phosphorylation is discussed.