Supplemental macronutrients and microbial fermentation products improve the uptake and transport of foliar applied zinc in sunflower (Helianthus annuus L.) plants. Studies utilizing micro X-ray florescence

Abstract

Enhancing nutrient uptake and the subsequent elemental transport from the sites of application to sites of utilization is of great importance to the science and practical field application of foliar fertilizers. The aim of this study was to investigate the mobility of various foliar applied zinc (Zn) formulations in sunflower (Helianthus annuus L.) and to evaluate the effects of the addition of an organic biostimulant on phloem loading and elemental mobility. This was achieved by application of foliar formulations to the blade of sunflower (H. annuus L.) and high-resolution elemental imaging with micro X-ray fluorescence (μ-XRF) to visualize Zn within the vascular system of the leaf petiole. Although no significant increase of total Zn in petioles was determined by inductively-coupled plasma mass-spectrometer, μ-XRF elemental imaging showed a clear enrichment of Zn in the vascular tissues within the sunflower petioles treated with foliar fertilizers containing Zn. The concentration of Zn in the vascular of sunflower petioles was increased when Zn was applied with other microelements with EDTA (commercial product Kick-Off) as compared with an equimolar concentration of ZnSO4 alone. The addition of macronutrients N, P, K (commercial product CleanStart) to the Kick-Off Zn fertilizer, further increased vascular system Zn concentrations while the addition of the microbially derived organic biostimulant “GroZyme” resulted in a remarkable enhancement of Zn concentrations in the petiole vascular system. The study provides direct visualized evidence for phloem transport of foliar applied Zn out of sites of application in plants by using μ-XRF technique, and suggests that the formulation of the foliar applied Zn and the addition of the organic biostimulant GroZyme increases the mobility of Zn following its absorption by the leaf of sunflower.

The Effectiveness of Foliar Applications of Zinc and Biostimulants to Increase Zinc Concentration and Bioavailability of Wheat Grain

“…The results of the present study, in which the addition of SE or MI did not enhance the effects of the foliar Zn applications on grain concentration, are in part contradicting with the previous reports. For example, Tian et al [14] reported that foliar application of microbial incubates greatly enhanced the uptake and movement of foliar-applied Zn in sunflower. Several studies on horticultural crops have also shown that soil applications of seaweed extracts were able to improve uptake of Zn and other nutrients [33][34][35].…”

“…Most of the studies assessing the effect of these biostimulants have focused on promoting plant growth and productivity [13]; only a few studies have investigated the impact of foliar biostimulants on the uptake of micronutrients in plants, including Zn. For example, Tian et al [14] reported that foliar spray microbial inoculants increased the movement of leaf-applied Zn in sunflower. Koksal et al [15] showed that leaf-applied amino acid chelate in pear increased leaf Zn content.…”

Innovative bio-products for agriculture

“…Tian et al [24] supplemented macronutrients and microbial fermentation products to improve the uptake and transport of foliarly applied zinc in sunflower (Helianthus annuus) by the micro X-ray florescence method when microbially derived organic biostimulant "GroZyme" was applied. Mobility of Zn from different preparations and phloem loading as the result of using an organic biostimulant were determined.…”

Biostimulants in Agriculture

“…Evidence that biostimulants may enhance macro nutrient uptake has been reported previously (Calvo et al, 2014;Rose et al, 2014) and have been ascribed to an effect on sink activity or stimulation of nitrogen metabolism. Foliar application of a biostimulant derived from microbial fermentation of cereal grains (Tian et al, 2015) greatly enhanced the movement of foliar applied zinc in sunflower. Using high resolution elemental mapping techniques (µ-Xray Florescence) the movement of Zn to the phloem following application of a combination of biostimulant and zinc sulfate was elegantly demonstrated.…”