利用綠豆左旋多巴增加種子鐵含量

Abstract

長久以來，缺鐵影響著人類健康，因此充足之鐵營養相當重要，利用生物營養強化 (biofortification) 增加農作物中微量營養元素含量是解決此問題具有前景之方法。但是，有鑑於基因改造生物在環境與安全上之疑慮，使用基因工程實現之營養強化稻米並未被大眾完全接受；而相較於傳統育種速度緩慢且成功率低，生物刺激素 (biostimulant) 不受限於特定作物與品種之特性使其應用既快速且有通用性。本篇研究測試 L-DOPA 作為生物刺激素應用於鐵營養強化上，結果顯示在不影響阿拉伯芥種子產量之情況下，施用 L-DOPA 可以增加種子中之鐵含量。由於在田間施用外源 L-DOPA 不方便又昂貴，因此探討了以綠豆間作作為 L-DOPA 供應者之可能性，並透過定量種子中 L-DOPA含量以鑑定出製造 L-DOPA 之綠豆品種。然而，當阿拉伯芥與綠豆間作時，阿拉伯芥之生長受到 L-DOPA 以外之化感物質 (allelochemicals) 抑制。根據這些結果判斷，若施用得當，L-DOPA 仍具有潛力作為鐵營養強化之生物刺激素；綠豆作為L-DOPA供應者之合適性則仍需要更進一步研究。綜合上述，本篇研究可為藉由生物刺激素實現生物營養強化之相關研究提供參考。

Lack of iron (Fe) affects human health for a long time; therefore, appropriate Fe nutrition is important. To address the issue, biofortification that increases micronutrient contents in crops is a promising approach. Biofortification of rice achieved using genetic engineering is not well accepted by the public due to environmental and safety concerns over GMOs. Traditional breeding is slow and has only limited success. Biostimulants constitute a fast and versatile solution because they are not restricted to a particular crop or cultivar. In this study, L-DOPA was tested as a biostimulant for Fe biofortification and was shown to increase Fe content in Arabidopsis seeds without affecting the yield. Because the exogenous application of L-DOPA in the field is inconvenient and expensive, the use of mungbean as a L-DOPA donor by intercropping was investigated. Mungbean cultivars that produce L-DOPA were identified by quantifying L-DOPA in their seeds. However, Arabidopsis exhibited growth inhibition when intercropped with mungbean caused by allelochemicals other than L-DOPA. Based on these results, it is suggested that L-DOPA might be a potential biostimulant for Fe biofortification if applied properly, while further studies are needed to evaluate the suitability of mungbean as the donor. This study could be a reference for achieving biofortification through biostimulants in related studies.