Morohashi Yukio
Department of Regulatory Biology, Faculty of Science, Saitama University, Urawa, Saitama 338-8570, Japan. moro.post.saitama-u.ac.jp
J Exp Bot. 2002 Jul;53(374):1643-50. doi: 10.1093/jxb/erf012.
Peroxidase activity developed specifically in the micropylar region of the endosperm of imbibed tomato seeds prior to radicle emergence. The activity was first detected approximately 24 h after the start of imibibition (6 h before radicle emergence) and increased markedly thereafter. In the lateral portion of the endosperm, peroxidase activity was undetectable for the first 2 d after the start of imbibition. Although the activity in the lateral endosperm became detectable 3 d after imbibition, the extent of the development of the activity was slight. The localization of peroxidase activity in the micropylar endosperm 2 d after the start of imbibition was confirmed by tissue printing analyses. When the endosperm tissues were wounded, there was an enhancement of the enzyme activity at the wounded region. H2O2 was formed at the expense of NADH only in the presence of Mn2+ and dinitrophenol by the extract from the micropylar endosperm in which peroxidase activity was present. The presence of H2O2 in the micropylar portion of the endosperm was shown histochemically. The possible functions of the peroxidases that develop in the endosperm of tomato seeds are discussed.
在番茄种子胚根伸出之前，过氧化物酶活性特异性地在吸胀种子胚乳的珠孔区域出现。该活性在吸胀开始后约24小时（胚根伸出前6小时）首次被检测到，此后显著增加。在胚乳的外侧部分，吸胀开始后的头两天未检测到过氧化物酶活性。尽管外侧胚乳中的活性在吸胀3天后变得可检测到，但活性发展的程度很小。通过组织印迹分析证实了吸胀开始后2天珠孔胚乳中过氧化物酶活性的定位。当胚乳组织受伤时，受伤区域的酶活性增强。仅在存在Mn2+和二硝基苯酚的情况下，由存在过氧化物酶活性的珠孔胚乳提取物以NADH为代价形成H2O2。通过组织化学方法显示了胚乳珠孔部分中H2O2的存在。讨论了番茄种子胚乳中发育的过氧化物酶的可能功能。
