倒伏是玉米高产栽培中导致产量严重下降的关键性限制因素之一,应用植物生长调节剂乙烯利或复配剂改善玉米茎秆质量、提高抗倒能力,是解决玉米倒伏的有效途径.本研究以玉米杂交种农大108、鲁单981及其相应亲本许178、黄C、齐319和1x9801为材料,在拔节期叶面喷施200 mg L-1乙烯利药液,研究了乙烯利对不同基因型玉米株型及其生理生化特征的影响.结果表明,乙烯利处理显著降低了农大108、鲁单981的株高和穗位高,特别是显著抑制了基部第1至6节间伸长；乙烯利处理显著提高了基部伸长节间中的苯丙氨酸解氨酶(PAL)和吲哚乙酸氧化酶(IAAO)活性,降低了基部伸长节间中生长素(IAA)和赤霉素(GA4)含量,增加了脱落酸(ABA)的积累.乙烯利处理显著降低了亲本许178、黄C、齐319和1x9801的株高和穗位高,显著缩短了基部节间长度；乙烯利处理后显著提高了基部伸长节间PAL和IAAO活性,显著降低了节间IAA和GA4含量,提高了脱落酸含量,降低了GAdABA比值.结合植株性状和生理生化特征分析,杂交种对乙烯利调控反应敏感性差异是由其双亲对乙烯利反应差异造成的,表现在乙烯利处理父母本间株高、穗位高、PAL和IAAO活性以及内源激素含量变化上存在显著差异.%Lodging is one of the key limiting factors causing serious yield decline in maize cultivation, the plant growth regulator ethephon and its complex formulation are applied to improve quality and lodging-resistance ability of stalks, which is an effective way to prevent stalk lodging. The responses in plant-type, physiological and biochemical characteristics of maize hybrid Nongda 108, Ludan 981 and their corresponding parents Xu 178, Huang-C, Qi 319, and 1x9801 varieties, were studied in field condition, with 200 mg L-1 ethephon foliage spray at jointing stage. The results showed that ethephon significantly inhibited the elongation of the first to sixth basal internodes for Nongda 108 and Ludan 981, the plant height and the ear height of Nongda 108 and Ludan 981 were significantly reduced. Ethephon remarkably increased the activities of phenylalanine ammonia lyase (PAL) and indole acetic acid oxidase (IAAO) and content of abscisic acid (ABA) in elongating internodes, and decreased contents of auxin (IAA) and gibberellin (GA4). The genetic traits were analyzed, the plant height and the ear height of Xu 178, Huang-C, Qi 319, and 1x9801 were significantly reduced after ethephon treating, and the length of basal internodes was shortened significantly. The PAL and IAAO activities in elongating internodes were significantly increased after ethephon treating. The endogenous IAA content of elongating intemodes was significantly decreased, ABA content was significantly increased, but GA4/ABA ratio was significantly decreased. It is indicated that the response differences to ethephon among different hybrids may be attributed to the different sensitivities of the parents lines, showing corresponding performance in plant height, ear height, PAL, IAAO activities and endogenous hormone levels.
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