Capsicum chinensis L. growth and nutraceutical properties are enhanced by biostimulants in a long-term period: chemical and metabolomic approaches.

Andrea Ertani,Diego Pizzeghello,Serenella Nardi,Santiago Sanchez-Cortes,Paolo Sambo,Ornella Francioso

doi:10.3389/fpls.2014.00375

Andrea Ertani, Diego Pizzeghello + Show 4 more

Open Access

https://doi.org/10.3389/fpls.2014.00375

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Abstract

Two biostimulants, one derived from alfalfa plants (AH) and the other obtained from red grape (RG), were chemically characterized using enzyme linked immuno-sorbent assays, Fourier transform infrared (FT-IR) and Raman spectroscopies. Two doses (50 and 100 mL L−1 for RG, and 25 and 50 mL L−1 for AH) of biostimulants were applied to Capsicum chinensis L. plants cultivated in pots inside a tunnel. The experimental design consisted of the factorial combination of treatment (no biostimulant, plus AH, plus RG) at three doses (zero, low, and high) and two time-course applications (at the second and fourth week after transplantation) and the effects were recorded at flowering and maturity. Both biostimulants contained different amounts of indoleacetic acid and isopentenyladenosine; the AH spectra exhibited amino acid functional groups in the peptidic structure, while the RG spectra showed the presence of polyphenols, such as resveratrol. These results revealed that at flowering, RG and AH increased the weights of fresh leaves and fruits and the number of green fruits, whereas at maturity, the biostimulants most affected the fresh weight and number of red fruits. At flowering, the leaves of the treated plants contained high amounts of epicatechin, ascorbic acid, quercetin, and dihydrocapsaicin. At maturity, the leaves of the treated plants exhibited elevated amounts of fructose, glucose, chlorogenic, and ferulic acids. Moreover, green fruits exhibited a high content of chlorogenic acid, p-hydroxybenzoic acid, p-coumaric acid and antioxidant activity, while both AH- and RG-treated red fruits were highly endowed in capsaicin. The 1H high-resolution magic-angle spinning (HRMAS)-nuclear magnetic resonance (NMR) spectra of red fruits revealed that both products induced a high amount of NADP+, whereas RG also increased glucose, fumarate, ascorbate, thymidine and high molecular weight species. Our results suggested that AH and RG promoted plant growth and the production of secondary metabolites, such as phenols.

Highlights

The long-term application of excessive doses of inorganic and organic fertilizers have resulted in a dramatic increased risk of nitrate and phosphate losses to aquatic ecosystems (Pizzeghello et al, 2011; Sebilo et al, 2013), which subsequently cause pollution and a reduction in environmental health
alfalfa hydrolyzed (AH) strongly differed from red grape (RG) for pH value (5.9 and 2.9, respectively) (P ≤ 0.05), total organic carbon (TOC) (18.8 and 1.23 %) (P ≤ 0.05), total phenols (2576 and 970 mg L−1) (P ≤ 0.05), and IAA (18.46 and 2.92 nmol mg−1 C) (P ≤ 0.05)
Smaller differences were found in the amount of total sugars (P ≤ 0.05) and IPA, which were slightly higher in RG (5700 mg L−1 and 0.073 nmol mg−1 C, respectively) compared to AH (4642 mg L−1 and 0.055 nmol mg−1 C, respectively)

Summary

Introduction

The long-term application of excessive doses of inorganic and organic fertilizers have resulted in a dramatic increased risk of nitrate and phosphate losses to aquatic ecosystems (Pizzeghello et al, 2011; Sebilo et al, 2013), which subsequently cause pollution and a reduction in environmental health. One interesting research focus in the field of agriculture is the study of specific bio-products, which are capable of positively influencing plant growth and, at the same, enabling the reduction of fertilizer rates. Among these bio-products include biostimulants, which have become more important due to their organic origin, which include cultivation wastes, fruit and skin processing, and their very low application doses.

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