Next Article in Journal
Rice Blast: A Disease with Implications for Global Food Security
Next Article in Special Issue
Distillery Anaerobic Digestion Residues as Fertilizers for Field Vegetable Crops: Performance and Efficiency in Mid-term Successions
Previous Article in Journal
SSR Marker-Assisted Management of Parental Germplasm in Sugarcane (Saccharum spp. hybrids) Breeding Programs
Previous Article in Special Issue
Effect of Fertilization on Yield and Quality of Sisymbrium officinale (L.) Scop. Grown as Leafy Vegetable Crop
Open AccessArticle

Morphological and Physiological Responses Induced by Protein Hydrolysate-Based Biostimulant and Nitrogen Rates in Greenhouse Spinach

1
Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, 81100 Caserta, Italy
2
Department of Agriculture and Forest Sciences, University of Tuscia, 01100 Viterbo, Italy
3
Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
4
Council for Agricultural Research and Economics (CREA)—Research Center for Cereal and Industrial Crops, 81100 Caserta, Italy
5
Italpollina USA Inc., Anderson, IN 46016, USA
6
Department of Vegetable Crops, Agricultural Research Institute, 1516 Nicosia, Cyprus
7
Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria (CREA), Centro di Ricerca Orticoltura e Florovivaismo (CREA-OF), 84098 Pontecagnano Faiano, Italy
*
Authors to whom correspondence should be addressed.
Agronomy 2019, 9(8), 450; https://doi.org/10.3390/agronomy9080450
Received: 23 July 2019 / Revised: 9 August 2019 / Accepted: 12 August 2019 / Published: 14 August 2019
(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)
Plant-derived protein hydrolysates (PHs) are gaining prominence as biostimulants due to their potential to improve yield and nutritional quality even under suboptimal nutrient regimens. In this study, we investigated the effects of foliar application of a legume-derived PH (0 or 4 mL L−1) on greenhouse baby spinach (Spinacia oleracea L.) under four nitrogen (N) fertilization levels (0, 15, 30, or 45 kg ha−1) by evaluating morphological and colorimetric parameters, mineral composition, carbohydrates, proteins, and amino acids. The fresh yield in untreated and biostimulant-treated spinach plants increased in response to an increase in N fertilization from 1 up to 30 kg ha−1, reaching a plateau thereafter indicating the luxury consumption of N at 45 kg ha−1. Increasing N fertilization rate, independently of PH, lead to a significant increase of all amino acids with the exception of alanine, GABA, leucine, lysine, methionine, and ornithine but decreased the polyphenols content. Interestingly, the fresh yield at 0 and 15 kg ha−1 was clearly greater in PH-treated plants compared to untreated plants by 33.3% and 24.9%, respectively. This was associated with the presence in of amino acids and small peptides PH ‘Trainer®’, which act as signaling molecules eliciting auxin- and/or gibberellin-like activities on both leaves and roots and thus inducing a “nutrient acquisition response” that enhances nutrients acquisition and assimilation (high P, Ca, and Mg accumulation) as well as an increase in the photochemical efficiency and activity of photosystem II (higher SPAD index). Foliar applications of the commercial PH decreased the polyphenols content, but on the other hand strongly increased total amino acid content (+45%, +82%, and +59% at 0, 15, and 30 kg ha−1, respectively) but not at a 45-kg ha−1-rate. Overall, the use of PH could represent a sustainable tool for boosting yield and nitrogen use efficiency and coping with soil fertility problems under low input regimens. View Full-Text
Keywords: natural biostimulants; nitrate; nitrogen use efficiency; amino acids; mineral profile; nutritional quality; Spinacia oleracea L. natural biostimulants; nitrate; nitrogen use efficiency; amino acids; mineral profile; nutritional quality; Spinacia oleracea L.
Show Figures

Figure 1

MDPI and ACS Style

Carillo, P.; Colla, G.; Fusco, G.M.; Dell’Aversana, E.; El-Nakhel, C.; Giordano, M.; Pannico, A.; Cozzolino, E.; Mori, M.; Reynaud, H.; Kyriacou, M.C.; Cardarelli, M.; Rouphael, Y. Morphological and Physiological Responses Induced by Protein Hydrolysate-Based Biostimulant and Nitrogen Rates in Greenhouse Spinach. Agronomy 2019, 9, 450.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop