ABSTRACT

Wheat is the main staple crop in Iran and thus of critical importance in human nutrition. This study was conducted to investigate the effect of individual and co-inoculation of azotobacter chroococcum bacteria (A. chroococcum) and a species (Rhizophagus irregularis) of arbuscular mycorrhizal fungi (AMF) on improving the nutritional quality of bread wheat grain. We performed a pot experiment, in which the effects of R. irregularis and A. chroococcum inoculation, and zinc (Zn) fertilization [0, 4.4, and 8.8 mg (kg)⁻¹] to cadmium (Cd)-spiked soil on increasing the Zn bioavailability and reducing the Cd concentration of wheat grains were tested. Inoculation with A. chroococcum increased the rate of root colonization by R. irregularis. Root colonization with AM fungus significantly reduced the grain Cd concentration especially after co-inoculation with A. chroococcum and soil application of ZnSO₄ fertilizer. Mycorrhized plants, compared to non-mycorrhized plants had considerably higher grain concentrations of phosphorous (P) and nitrogen (N), which were affected by the application rate of ZnSO₄ and co-inoculation with A. chroococcum. The response of grain Zn concentration to mycorrhization was dependent on the rate of Zn fertilization and inoculation with A. chorococum. Single inoculation with R. irregularis increased the concentration of phytic acid (PA) and also the molar ratio of PA:Zn in grains, which may have resulted in reduced Zn bioavailability. In contrast, double inoculation of plants with R. irregularis and A. chroococcum reduced the molar ratio of PA:Zn especially after application of ZnSO₄. This study suggests that dual inoculation of wheat plants with A. chroococcum and R. irregularis together with Zn fertilization may enhance the nutritional quality of wheat grains.

摘要

小麦是伊朗的主要主粮作物，因此对人类营养至关重要。这项研究旨在探讨的个人和共同接种的效果圆褐固氮菌细菌（A. chroococcum）和种（Rhizophagus irregularis）的丛枝菌根真菌（改善面包小麦的营养品质AMF）。我们进行了一个盆栽实验，其中接种了不规则红球藻和A. chroococcum，以及将锌 (Zn) 施肥 [ 0、4.4和 8.8 mg (kg) ^-1 ] 添加到镉 (Cd) 掺入的土壤中对增加测试了小麦籽粒的 Zn 生物利用度和降低 Cd 浓度。接种A. chroococcum增加了不规则 R.的根部定植率。AM 真菌根系定植显着降低了谷物 Cd 浓度，尤其是在与A. chroococcum共同接种和土壤施用 ZnSO ₄肥料后。与非菌根植物相比，菌根植物具有相当高的磷 (P) 和氮 (N) 谷粒浓度，这受到 ZnSO ₄的施用率和与A. chroococcum共同接种的影响。谷物锌浓度对菌根形成的响应取决于锌施肥率和接种A. chorococum 的速度。单次接种不规则R.增加了植酸 (PA) 的浓度以及谷物中 PA:Zn 的摩尔比，这可能导致 Zn 的生物利用度降低。相比之下，植物双接种不规则红球藻和A. chroococcum降低了 PA:Zn 的摩尔比，尤其是在施用 ZnSO _{4 之后}。本研究表明，小麦植株同时接种A. chroococcum和R. wrongis并配施锌肥可提高小麦籽粒的营养品质。