He C. J., Drew M. C., Morgan P. W.
Department of Soil and Crop Sciences (C.-J.H., P.W.M.), and Department of Horticultural Sciences (M.C.D.), Texas A&M University, College Station, Texas 77843.
Plant Physiol. 1994 Jul;105(3):861-865. doi: 10.1104/pp.105.3.861.
Either hypoxia, which stimulates ethylene biosynthesis, or temporary N starvation, which depresses ethylene production, leads to formation of aerenchyma in maize (Zea mays L.) adventitious roots by extensive lysis of cortical cells. We studied the activity of enzymes closely involved in either ethylene formation (1-amino-cyclopropane-1-carboxylic acid synthase [ACC synthase]) or cell-wall dissolution (cellulase). Activity of ACC synthase was stimulated in the apical zone of intact roots by hypoxia, but not by anoxia or N starvation. However, N starvation, as well as hypoxia, did enhance cellulase activity in the apical zone, but not in the older zones of the same roots. Cellulase activity did not increase during hypoxia or N starvation in the presence of aminoethoxyvinylglycine, an inhibitor of ACC synthase, but this inhibition of cellulase induction was reversed during simultaneous exposure to exogenous ethylene. Together these results indicate both the role of ethylene in signaling cell lysis in response to two distinct environmental factors and the significance of hypoxia rather than anoxia in stimulation of ethylene biosynthesis in maize roots.
刺激乙烯生物合成的低氧或抑制乙烯产生的暂时氮饥饿，都会通过皮层细胞的广泛裂解，导致玉米（Zea mays L.）不定根中通气组织的形成。我们研究了与乙烯形成（1-氨基环丙烷-1-羧酸合酶[ACC合酶]）或细胞壁溶解（纤维素酶）密切相关的酶的活性。低氧刺激完整根顶端区域的ACC合酶活性，但缺氧或氮饥饿则不会。然而，氮饥饿以及低氧确实会增强顶端区域的纤维素酶活性，但同一根的较老区域则不会。在存在ACC合酶抑制剂氨基乙氧基乙烯基甘氨酸的情况下，低氧或氮饥饿期间纤维素酶活性不会增加，但在同时暴露于外源乙烯时，这种对纤维素酶诱导的抑制作用会被逆转。这些结果共同表明了乙烯在响应两种不同环境因素时信号传导细胞裂解中的作用，以及低氧而非缺氧在刺激玉米根中乙烯生物合成中的重要性。
