茉莉酸与茉莉酸甲酯预处理对干旱胁迫下棉花种子萌发和种苗生理特性的影响

以新疆棉花主栽品种‘新陆早17’为材料,采用PEG模拟水分胁迫的方法,探讨不同浓度(0.025、0.25、2.5、25、250μmol/L)外源激素茉莉酸(JA)和茉莉酸甲酯(MeJA)预处理对23%PEG-6000模拟干旱胁迫下棉花种子萌发及种苗生长、水分含量、根系活力、脯氨酸和氧化损伤的影响,为JA和MeJA在棉花生产中的合理使用提供依据。结果显示:(1)JA和MeJA预处理能够显著缓解23%PEG-6000对棉花种子的干旱胁迫伤害,且2.5μmol/L MeJA预处理使干旱胁迫下棉花种子的发芽率和发芽势达到最高(70.0%、63.3%),比23%PEG-600干旱胁迫对照分别提高了49.99%、72.70%;0.025μmol/L JA预处理使干旱胁迫下棉花种子的发芽指数和活力指数达到最高(27.3、203.1),比对照分别提高了68.14%、190.29%;2.5μmol/L JA预处理使干旱胁迫下根系活力达到最高,比对照提高266.68%。(2)两种激素预处理均能够使干旱胁迫下棉花种苗的脯氨酸含量显著上升,丙二醛含量显著降低。研究表明,适宜浓度外源JA和MeJA能够显著缓解干旱胁迫对棉花种子伤害,促进棉花种子萌发、种苗生长,增强根系代谢和减轻种苗的氧化损伤,从而增强其耐旱能力;MeJA预处理效果要好于JA预处理,且干旱条件下棉花种子萌发及种苗生长的最适MeJA预处理浓度为2.5μmol/L,而0.025μmol/L JA则为棉花种子萌发的最适作用浓度,0.25和2.5μmol/L则分别为种苗生长过程中促进作用最明显的浓度。

干旱胁迫下连翘种苗对外源茉莉酸甲酯的生理生化响应

目的:探究干旱胁迫下茉莉酸甲酯(MeJA)对连翘种子萌发及种苗生理特性的影响。方法:以连翘Forsythia suspensa和狭叶连翘Forsythia viridissima为材料,研究不同浓度外源MeJA对干旱胁迫下种子萌发及种苗的脯氨酸含量、渗透势、丙二醛含量和膜透性的影响。结果:MeJA处理能显著缓解干旱胁迫对种子的伤害,促进种子萌发。连翘以150μmol/L MeJA浸种效果最佳,其发芽率、发芽势、发芽指数和活力指数分别比对照提高81.67%、97.51%、58.51%和45.22%(P<0.05);狭叶连翘以200μmol/L MeJA浸种效果最佳,其发芽率、发芽势、发芽指数和活力指数分别比对照提高74.59%、88.85%、50.89%和35.17%(P<0.05)。MeJA浸种均能使干旱胁迫下连翘和狭叶连翘种苗的脯氨酸含量显著上升,渗透势显著下降,丙二醛含量和膜透性显著降低,从而增强其耐旱能力。连翘以150μmol/L和200μmol/L MeJA浸种效果最佳,脯氨酸含量比对照提高78.18%,渗透势、丙二醛含量、膜透性比对照分别降低80.13%、53.81%、47.92%(P<0.05);狭叶连翘以200μmol/L MeJA浸种效果最佳,脯氨酸含量比对照提高78.36%,渗透势、丙二醛含量、膜透性比对照分别降低65.84%、47.78%、50.28%(P<0.05)。结论:适宜浓度的外源MeJA浸种,可有效提高干旱胁迫下种苗的抗旱性。连翘最适的MeJA浸种浓度为150μmol/L和200μmol/L,狭叶连翘最适的MeJA浸种浓度为200μmol/L。

Methods of Testing Seed and Seedling Physiological Traits for the Improvement of Rapeseed Yield Stability

The presented work is based on laboratory testing of seed germination speed, emergence and seedling growth under different stress conditions simulated by subnormal water revel, extreme high and low temperatures. It allows one to eliminate the plant materials （initial breeding materials and cultivars） which do not tolerate extreme temperatures and temperature changes during germination, have low water use efficiency and is intolerant to abiotic stressors all right at the seed level. It was confirmed that these genotypes also have poor t^eld emergence and initial root growth implications for further vegetation periods, mainly for over wintering and spring regeneration which has significant influence on the yield. The method also represents the tool for screening genetic resources with the resistance to the abiotic stressors and this technology process is also acceptable for other crops. The results confirm the importance of the seed and root characteristics for crop production. The deteriorating quality of soil in recent years, increasing variability of weather and long periods of drought directly support the need to intensify activities in this research. Obtained results also show the influence of seed quality characteristics on roots and above ground parts of the plant. A relationship exists also vice versa.