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冷(热)激对干旱胁迫下玉米活性氧清除及膜脂过氧化的调控机制 被引量:14
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作者 张永福 黄鹤平 +3 位作者 银立新 陈泽斌 刘佳妮 彭声静 《江苏农业科学》 北大核心 2015年第5期56-60,共5页
为了揭示冷(热)激对干旱胁迫下玉米活性氧清除系统及膜脂过氧化的调控机制,以会单2号幼苗为试材,经冷(热)激预处理后,待苗长至50 cm左右时用15%聚乙二醇(PEG-6000)模拟干旱处理。结果表明,随着干旱胁迫时间的延长,玉米叶片的相对电导率... 为了揭示冷(热)激对干旱胁迫下玉米活性氧清除系统及膜脂过氧化的调控机制,以会单2号幼苗为试材,经冷(热)激预处理后,待苗长至50 cm左右时用15%聚乙二醇(PEG-6000)模拟干旱处理。结果表明,随着干旱胁迫时间的延长,玉米叶片的相对电导率、丙二醛含量显著增加,质膜遭到损害,其中对照质膜的损害明显比冷(热)激处理的严重;SOD和POD活性在干旱胁迫初期迅速升高,随着胁迫时间的延长而逐渐变缓并略有下降,冷(热)激处理对干旱胁迫下玉米叶片这2种酶活性的响应差异较大,具有相互协调的作用;冷(热)激能显著降低玉米叶片在干旱胁迫下O-2·产生速率和H2O2含量;叶绿素和类胡萝卜素含量在干旱胁迫初期呈现上升趋势,但随后便有不同程度的下降,其中冷(热)激处理能够显著地减缓这种下降的速率;在干旱胁迫初期,各试材根系活力的下降幅度较小,但到了干旱胁迫中期以后,各试材根系活力迅速下降,其中冷(热)激预处理能够显著减缓根系活力的下降速率。可见,冷(热)激处理能够显著增强干旱胁迫下玉米叶片活性氧清除系统的功效,减轻膜质过氧化对玉米叶片的伤害,增强其耐旱性,其中以4℃冷激处理的效果最显著。 展开更多
关键词 玉米 () 干旱胁迫 活性氧 膜质过氧化 调控机制
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Nonmechanical criteria proposed for prediction of hot tearing sensitivity in 2024 aluminum alloy 被引量:4
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作者 M.H.GHONCHEH S.G.SHABESTARI +1 位作者 A.ASGARI M.KARIMZADEH 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第5期848-857,共10页
Two theoretical criteria represented by Katgerman, and Clyne and Davies for prognosticating hot tearing sensitivity were compared. Both unrefined and grain-refined samples of Al2024 alloy were solidified at various co... Two theoretical criteria represented by Katgerman, and Clyne and Davies for prognosticating hot tearing sensitivity were compared. Both unrefined and grain-refined samples of Al2024 alloy were solidified at various cooling rates ranging from 0.4 to 17.5 °C/s. Thermal analysis was used to detect dendrite coherency point and temperature of eutectic reaction. Curves of solid and liquid fractions were plotted based on Newtonian method to determine hot tearing susceptible areas. The experimental results show that the most susceptible zone in which hot tearing can occur in Al2024 is where Al_2CuMg intermetallic compound forms as a eutectic phase at last stage of mushy-state interval. Also, both criteria are in a good agreement with each other at high cooling rates used in direct-chill casting process while Clyne and Davies' model is more acceptable to determine hot tearing tendency from low to medium cooling rates. 展开更多
关键词 2024 aluminum alloy dendrite coherency direct-chill casting thermal analysis hot tearing
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