中文摘要：

为明确小麦药隔期、孕穗期和开花期三个阶段低温对麦穗的伤害以及小麦对低温的生理响应，以春性品种扬麦16和半冬性品种徐麦30为试验材料，利用人工气候室模拟低温逆境，研究药隔期、孕穗期和开花期低温处理后小麦产量和生理特性的变化。结果表明，药隔期-2℃胁迫24h，穗数显著下降，两品种产量平均下降了25．62％；孕穗期0℃胁迫24h，穗数和穗粒数显著下降，产量平均降低了21．00％；开花期6℃胁迫48h，粒重显著下降，产量降低了12．28％。三个阶段低温处理后，叶片可溶性蛋白、游离脯氨酸、脱落酸及丙二醛含量随胁迫程度的加重而升高；赤霉素（GA3）含量下降。药隔期、孕穗期低温迫胁后，两品种单株钾、钙及钼的积累量较对照上升，随着胁迫时间的延长，钾、钙的积累量下降；开花期低温胁迫下植株钾、钙的积累量较对照先升后降，钼积累量较对照呈下降趋势。三个阶段低温处理后徐麦30的应激反应虽强于扬麦16，但药隔期、孕穗期低温对徐麦30幼穗伤害重于扬麦16，产量降幅也略高于扬麦16。

英文摘要：

To determine the effects of low temperature on wheat ear and the related physiological characteristics at anther connective, booting and anthesis stages, respectively, cold stress was simulated using artificial temperature-controlled phytotrons to study grain yield and physiological characteristics of spring wheat cultivar Yangmai 16（YM 16） and semi-winter wheat cultivar Xumai 30（XM 30）. It is shown that the ear number per plant of these two cultivars was significantly decreased under the treat- ment of -2 ℃ for 24 h,and the grain yield was decreased by 25.62~ at anther connective stage. The grain yield of two cultivars declined by 21.00 % under the temperature of 0 ℃ for 24 h at booting stage 280% Thecontents of soluble sugar, proline, abscisic acid（ABA） and malondialdehyde（MDA） in leaves were increased under cold stress, while the content of gibberellins （GA3） was decreased under the low temperature during the three stages. Compared to the control, the potassium, calcium and molybdenum accumulation amount by wheat plant were increased at the beginning and then declined during the anther connective to anthesis stages. Molybdenum accumulation amount was lower than that of the control. The anti-cold stress effect in leaves of wheat cultivar XM 30 was stronger than that of YM 16 in a short time after cold stress during the three stages, while, young spike of XM 30 was damaged more seriously than that of YM 16 at anther connective and booting stages,which caused the grain yield of XM 30 was decreased more than that of YM 16.