Table 1_Aerial root formation in Oaxacan maize (Zea mays) landraces persists into the adult phase and is minimally affected by soil nitrogen and ambient humidity.docx

Maize (Zea mays L.) is the most widely produced crop in the world, and conventional production requires significant amounts of synthetic nitrogen fertilizer, which has negative economic and environmental consequences. Maize landraces from Oaxaca, Mexico, can acquire nitrogen from nitrogen-fixing bacteria that live in a mucilage secreted by aerial nodal roots. The development of these nodal roots is a characteristic traditionally associated with the juvenile vegetative stage of maize plants. However, mature Oaxacan landraces develop many more nodes with aerial roots than commercial maize varieties. Our study shows that Oaxacan landraces develop aerial roots during the juvenile and adult vegetative phases and even during early flowering under greenhouse and field conditions. Surprisingly, the development of these roots was only minimally affected by soil nitrogen and ambient humidity. These findings are an essential first step in developing maize varieties to reduce fertilizer needs in maize production across different environmental conditions.

玉米（Zea mays L.）是全球产量最高的作物，传统种植模式需施用大量合成氮肥，由此带来一系列负面经济与环境效应。产自墨西哥瓦哈卡州的玉米地方品种，可借助生长在其气生节根所分泌黏液中的固氮细菌获取氮素。这类节根的发育，传统上被认为仅与玉米植株的幼龄营养生长期相关联。但相较于商业化玉米品种，成熟的瓦哈卡地方品种会长出更多带有气生根的茎节。本研究证实，瓦哈卡玉米地方品种在幼龄及成年营养生长期，甚至在温室与田间试验条件下的开花早期阶段，均可发育气生根。令人意外的是，这类气生根的发育仅受到土壤氮素与环境湿度的微弱影响。上述发现可为培育适应不同环境条件、降低玉米生产氮肥依赖的新品种奠定关键的基础性第一步。