Nutrients uptake and chemical speciation reveal species-specific mineral nutrition patterns in four plant species in vitro

Abstract

Although differences in mineral requirements among plant species, cultivars, and developmental stages are well documentedunder ex vitro conditions, few studies have quantified such variations across species growing in vitro under comparableexperimental and analytical conditions within a single laboratory framework, despite the use of species-specificculture protocols. Here, we examined the mineral nutrition of four species with contrasting tissue culture responses andgrowth habits (Nicotiana tabacum, Selenicereus costaricensis, Guadua angustifolia, and Dendrocalamus giganteus) grownon Murashige and Skoog (MS) medium. We evaluated tissue mineral nutrient accumulation, net utilization efficiency, andchemical speciation. Net utilization efficiency is used here as an integrative indicator defined as the percentage of thenutrient initially supplied in the medium that is recovered in plant tissues after one culture cycle. Mineral concentrationsin plant tissues and in the culture medium were quantified by Inductively Coupled Plasma Optical Emission Spectrometry(ICP-OES), except for N, which was determined by dry combustion. For most nutrients, the net utilization efficiencywas less than 50%, with S. costaricensis and G. angustifolia showing the lowest values (< 25% and < 5%, respectively).However, D. giganteus recovered ≥50% of N, P, and S and increased aerial dry mass at 3.52 mg day⁻¹ within three weeks,whereas N. tabacum reached 4.17 mg day⁻¹ and showed near-complete P recovery. Nutrient allocation patterns also differedamong species: while N. tabacum and S. costaricensis accumulated more nutrients in aerial tissues, G. angustifoliastored several elements predominantly in the roots. Chemical speciation modeling of the MS medium showed that over90% of most nutrients were initially present as dissolved, operationally bioavailable species. Nevertheless, elements predictedto be less available (e.g., Cu and Fe) were recovered in substantial amounts in the plant tissues, suggesting dynamicchanges in speciation during culture. These findings show the importance of integrating tissue mineral nutrient accumulation,net utilization efficiency, and chemical speciation to better understand species-specific mineral nutrition patterns invitro and to provide a diagnostic framework that can guide the design of future, tailored media for specific species