【作者】 郁飞燕；

【导师】 李友军； 张灿军；

【作者基本信息】 河南科技大学 ， 作物， 2012， 硕士

【摘要】 干旱贯穿于小麦播种至收获的整个生育过程，是影响小麦生产的主要非生物限制因子，作物抗旱性研究成为植物抗逆性研究中的重中之重。在我国一些地区，经常出现春、秋干旱，甚至春夏秋三季连旱，从而导致小麦播期延迟，影响种子萌发，最终导致产量严重下降。本研究利用5%、10%、15%和20%PEG-6000溶液和0.25、0.5、1.0、和2.0μM Na₂SeO₃处理12个小麦品系种子，结合种子发芽率、胚芽长度和胚根长度从中筛选出对PEG-6000和Na₂SeO₃处理敏感品系9612，探讨PEG-6000处理抑制种子萌发和Na₂SeO₃处理促进种子萌发的生理特性，在此基础上，进一步研究在15%PEG-6000胁迫下，亚硒酸盐对9612种子萌发的作用效果及作用机制。结果显示，PEG处理抑制了α-淀粉酶活性，降低了萌发种子中可溶性糖、可溶性蛋白以及游离氨基酸含量，同时提高了种子呼吸速率和脯氨酸含量。相反，亚硒酸盐提高了α-淀粉酶活性和萌发种子中可溶性糖、可溶性蛋白以及游离氨基酸含量，因此PEG-6000处理抑制种子萌发和Na₂SeO₃处理促进种子萌发与影响到种子中可溶性糖以及游离氨基酸等从胚乳向胚根和胚芽中转运有关。在15%PEG-6000胁迫下，亚硒酸盐同样能显著提高小麦种子发芽率。与对照相比，亚硒酸盐虽能提高小麦种子中淀粉酶活性，但并未达到显著性差异。亚硒酸盐降低了种子中脯氨酸含量和过氧化氢酶活性，提高了POD和SOD活性。PEG胁迫降低了萌发小麦种子芽和根中钾、硫、钙、镁、铁、锌和锰含量。亚硒酸盐提高了芽中钾和锰含量，提高了根中钙、镁、锌和锰含量而降低了磷和铜含量。15%PEG-6000胁迫下较低浓度的亚硒酸盐提高了胚根中磷、钾、硫、镁、锌和锰含量，较高浓度的亚硒酸盐提高了胚芽中磷、钾、硫、镁、锌和锰含量。可见，在PEG-6000胁迫下，亚硒酸盐促进小麦种子萌发与调节多种营养元素在胚根和胚芽中分配以及提高萌发种子对干旱胁迫抗性有关。本项研究为利用硒提高小麦抗旱能力提供理论依据。更多还原

【Abstract】 Drought is a major abiotic factor limiting wheat production throughout thewhole reproductive process from sowing to harvest. Study on crop drought resistanceis most important in the research of plant stress resistance. In some areas of China,drought may occur during spring or autumn, or even continuous spring, summer andautumn, causing delays in wheat planting and seed germination, eventually leading tosevere yield degradation. In this study, a wheat strain of9612, susceptible to PEG-6000and Na₂SeO₃, was screened from12strains under PEG-6000treatments （5%,10%,15%and20%） and Na₂SeO₃treatments （0.25,0.5,1.0, and2.0μM） based on theresults of germination rate, the length of radicles, primary root and second roots, thenthe physiological characteristics of seed germination were investigatedunderlying inhibiton by PEG-6000and promotion by Na₂SeO₃. On this basis, furtherstudy was performed on the physiological mechanisms of seed germination promotedby Na₂SeO₃under15%PEG-6000stress. Results showed that α-amylase activity wasinhibited and the content of soluble sugar, soluble protein and free amino acid wasdecreased, while seed respiration rate and proline content were increased ingerminating seeds under PEG-6000treatments. On the contrary, α-amylase activitywas stimulated and the content of soluble sugar, soluble protein and free amino acidwas increased under selenite treatments. It suggested that PEG-6000inhibition andselenite promotion of seed germination were involved in the transport of solublesugars and free amino acids from endosperm to radicles and germs. Selenite couldsignificantly improve wheat seed germination rate under15%PEG-6000stress.Compared with the control, selenite could improve the activity of α-amylase ingerminating wheat seed, increase the content of soluble protein, soluble sugar and freeamino acid in germinating seed, however, no significant difference was showed.Meanwhile, proline content was reduced and SOD and POD activity were increased. Also, PEG stress decreased the content of potassium, sulfur, calcium, magnesium, iron,zinc, manganese in roots and sprouts of germinating wheat seeds. Selenite improvedthe content of potassium and manganese in sprouts and magnesium and manganese inroots, while decreased phosphorus and copper in roots. Lower concentrations ofselenite increased the content of phosphorus, potassium, sulfur, magnesium, zinc andmanganese in roots and higher levels of selenite improved phosphorus, potassium,sulfur, magnesium, zinc and manganese in sprouts under15%PEG-6000stress.Obviously, the promotion of germination of wheat seeds by selenite was involved inimproving stress-related resistance and mediating nutrient elements allocation inradicles and germs, thus promoted the germination of wheat seeds by decreasing theadverse effects of drought stress under PEG-6000stress. The study provides thetheoretical basis for the further application of selenium to increase drought resistanceability of germinating wheat seeds.更多还原