Effects of Citric Acid and Humic-like Substances on Yield, Enzyme Activities, and Expression of Genes Involved in Iron Uptake in Tomato Plants

Iron (Fe) deficiency is a common abiotic stress on plants growing in calcareous soils where low organic matter content, high carbonate–bicarbonate concentration, and pH precipitate Fe unavailable forms. Enzymatic activity mechanism for to access soil nutrients; enzymes such as H+-ATPase, phosphoenolpyruvate carboxylase (PEPC), the intracellular enzyme ferric reduction oxidase (FRO) are involved absorption. The effects of application citric acid (CA) humic-like substances (HLS) yield, PEPC, FRO activity, expression LeHA1, LePEPC1, LeFRO1 genes tomato grown under were studied. CA HLS improved SPAD units increased number harvested fruits yield per plant. Temporary alterations which reduced PEPC roots, documented. In leaf tissue, resulted lower LeHA1 LePEPC1 induction expression, whereas higher LeFRO1. with HLS, showed respectively. through nutrient solution combination Fe-chelate can improve nutrition potted by inducing temporal gene expression.