Can Foliar Pulverization with CaCl2 and Ca(NO3)2 Trigger Ca Enrichment in Solanum tuberosum L. Tubers?

Ana Rita F Coelho,João Caleiro,Paulo Legoinha,José C Ramalho,Isabel P Pais,Fernando C Lidon,Maria Manuela Silva,Carlos Galhano,Mauro Guerra,Inês Carmo Luís,José N Semedo,Maria Fernanda Pessoa ,A L Rodrigues ,Cláudia Campos Pessoa,Maria Graça Brito ,José Carlos Kullberg ,Roberta G Leitão,Fernando H Reboredo,Paula Scotti Campos ,Ana Coelho Marques

doi:10.3390/plants10020245

Ana Rita F Coelho, João Caleiro + Show 18 more

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https://doi.org/10.3390/plants10020245

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Abstract

This study aimed to assess the efficiency of Ca enrichment in tubers of three genotypes of Solanum tuberosum L., through foliar spraying with CaCl2 and Ca(NO3)2 solutions. In this context, soil heterogeneity of three potato-growing fields, as well as the implications of Ca accumulation among tissues and some quality parameters were assessed. Three potato varieties (Agria, Picasso and Rossi) were grown in three production fields and during the life cycle, four pulverizations with calcium chloride (3 and 6 kg ha−1) or calcium nitrate (0.5, 2 and 4 kg ha−1) were applied. For screening the potential phytotoxicity, using Agria as a test system, the potential synthesis of photoassimilates was determined, and it was found that after the 3rd Ca application, leaf gas exchanges were moderately (net photosynthesis), to strongly (stomatal conductance) affected, although without impact on Ca accumulation in tubers. At harvest, the average Ca biofortification index varied between 5–40%, 40–35% and 4.3–13% in Agria, Picasso and Rossi, respectively. Moreover, the equatorial region of the tubers in general showed that Ca accumulation prevailed in the epidermis and, in some cases, in inner areas of the potato tubers. Biofortified tubers with Ca also showed some significant changes in total soluble solids and colorimetric parameters. It is concluded that Ca enrichment of potato tubers through foliar spraying complemented the xylem mass flow of Ca from roots, through phloem redistribution. Both fertilizers showed similar efficiency, but Rossi revealed a lower index of Ca accumulation, eventually due to different metabolic characteristics. Although affected by Ca enrichment, potato tubers maintained a high quality for industrial processing.

Highlights

Calcium is an essential nutrient, namely for bone development and functioning of the circulatory system of the human population [1,2,3,4]
It was found that the Moledo field had a greater aptitude for accumulation of surface water, and/or infiltration, while Casal Galharda only presented 21% of the area with low drainage capabilities (Table 1)
The NDVI (Normalized Difference Vegetation Index) index indicated, as expected, that soils of the three experimental fields were dominantly without vegetation, except for the green areas, where the presented vegetation did not match the crops in this study (Figure 1A,D)

Summary

Introduction

Calcium is an essential nutrient, namely for bone development and functioning of the circulatory system of the human population [1,2,3,4]. Agronomic biofortification, a fast, reliable, sustainable, accessible, and cost-effective way to increase minerals content [8,9,10,11], can surpass Ca deficiency, allowing its enrichment in the edible parts of selected food crops. Relatively immobile in cells and not readily remobilized from the mature to the active growing parts of plants [5], is an essential macronutrient for plant growth and development, being required as Ca2±. It is a transduction agent, providing stability and integrity to the cell wall [14]. It plays a central role in stress responses [15]

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