Iron efficiency of different corn hybrids grown in nutrient solution culture

Growing Fe-efficient genotype(s) could be considered as a preferred genetic approach to tackle the widespread constraint of Fe-deficiency-/lime-induced chlorosis in crop grown on alkaline soil. This study aimed to investigate morphological and physiological traits linked to expression of Fe deficiency among four corn (Zea mays) including sweet (Z. mays sacchrata cvs. H403 and H404) and grain (Z. mays indentata cvs. H500 and H700) hybrids grown in nutrient solution using two Fe concentrations (5 and 50 µM Fe-ethylenediaminetetraacetic acid (Fe-EDTA)). Significant variation was found among studied hybrids in their tolerance to Fe-deficiency stress. Sweet corn hybrids were more sensitive to Fe deficiency as compared with grain corn hybrids and greater reduction was observed in their shoot dry matter at the 5 µM Fe-EDTA treatment. The greatest decrease in plant height, leaf area, and root and shoot dry matter weight under Fe-deficiency condition was found for H403 hybrid. No significant correlation was found between shoot and root Fe concentration with crop tolerance to Fe deficiency. Furthermore, different response of corn hybrids to Fe deficiency is an important factor, which has to be considered in Fe fertilizer recommendation as well as breeding programs.     

叶面喷施铁基纳米材料对大豆生长的影响及机制研究

为探究叶面喷施铁基纳米材料(NMs)对作物生长的影响及其潜在机制,利用水培试验探究了两种铁基NMs(γ-Fe2O3 NMs和Fe3O4 NMs)和Fe-EDTA对大豆生长的影响.先通过叶面喷施不同浓度(0、1、10、50 mg·L-1)的铁基NMs,确定最佳施用浓度(10 mg·L-1),再在最佳施用浓度下,比较两种NMs与Fe-EDTA对大豆生长和蔗糖转运的作用效果及机制.结果 表明,叶面喷施不同浓度铁基NMs对大豆地上部和地下部干质量、根长、根尖数、根体积均有促进作用,且效果随着浓度的升高呈现先增加后降低的趋势.10 mg·L-1为铁基NMs促进大豆生长的最佳浓度,且不同处理组的促生效果表现为γ-Fe2O3 NMs>Fe3O4 NMs>螯合铁肥(相同含铁量的Fe-EDTA).铁基NMs的缓释性及高表面活性使其比Fe-EDTA具有更高的生物可利用性,γ-Fe2O3 NMs处理的大豆根、茎、叶中铁含量是等量Fe-EDTA处理的1.29、1.09、1.24倍;10 mg·L-1γ-Fe2O3 NMs、Fe3O4 NMs、Fe-EDTA处理下,大豆净光合速率与对照组相比分别增加了62.7％、41.5％、30.7％,铁基NMs对大豆叶片蒸腾速率、气孔导度和胞间二氧化碳浓度的促进效果也明显高于Fe-EDTA;铁基NMs通过调控蔗糖转运相关基因(GmSWEET 15、GmSUT 2)的表达量,促进光合产物向根部的运输,增加大豆根冠比,促进根部养分(S、P、Ca、Mn、Cu)吸收.研究表明,叶面喷施纳米铁肥能够促进作物生长、蔗糖转运及养分吸收,且相对于传统铁肥其促进效果更为显著(P<0.05),这为铁基纳米肥在农业生产中的应用提供了理论依据.