Optimization of the Yield, Total Phenolic Content, and Antioxidant Capacity of Basil by Controlling the Electrical Conductivity of the Nutrient Solution

Xiaowei Ren,Michiko Takagaki,Wenshuo Xu,Na Lu,Yunfei Zhuang

doi:10.3390/horticulturae8030216

Xiaowei Ren, Michiko Takagaki + Show 3 more

Open Access

https://doi.org/10.3390/horticulturae8030216

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Journal: Horticulturae	Publication Date: Mar 1, 2022
Citations: 11	License type: CC BY 4.0

Affiliation: Chiba University

Abstract

Hydroponic cultivation using nutrient solution (NS) is the main cultivation method employed by plant factories with artificial lighting (PFALs). The electrical conductivity (EC) of NSs influences the yield and quality of vegetables. The purpose of this study was to optimize the yield and antioxidant accumulation of basil in a PFAL by EC management. In experiment 1, basil plants were grown under four different ECs (0.5, 1.0, 3.0, and 5.0 dS m−1) after transplanting. At 18 days after treatment, the highest levels of shoot fresh and dry weights, leaf fresh and dry weights, and leaf area were observed at an EC of 3.0 dS m−1. However, low-EC treatments (0.5 and 1.0 dS m−1) generated total phenolic content (TPC) and antioxidant capacities that were higher than those of other EC treatments (3.0 and 5.0 dS m−1). In experiment 2, basil plants were grown at an EC of 3.0 dS m−1 for 13 or 15 days, then treated with water or NS with low ECs (0.5 and 1.0 dS m−1) for 5 or 3 days before harvest. The short-term low-EC treatments, especially, water for 3 days and 0.5 dS m−1 for 5 days, significantly increased the TPC and antioxidant capacity of leaves without significantly decreasing the yields of basil, compared with the control. In conclusion, yield of basil was optimized with an EC of 3.0 dS m−1; however, the TPC and antioxidant capacity of basil were significantly increased by low ECs of 0.5 and 1.0 dS m−1. Short-term low-EC treatments (0.5 dS m−1 for 5 days or water for 3 days) could be used to promote the TPC and antioxidant capacity in leaves without sacrificing yield of basil significantly.

Highlights

Publisher’s Note: MDPI stays neutralPlant factories with artificial lighting (PFALs) are considered a high-end agricultural model that has many advantages over traditional agriculture
The shoot and leaf FW and leaf area increased significantly when the electrical conductivity (EC) value was increased from 0.5 to 3.0 dS m−1 and decreased slightly when the EC value was further increased to 5.0 dS m−1 (Figure 2A–C)
The shoot and leaf DW followed a similar trend as the shoot and leaf FW; the differences in shoot DW at EC values of 1.0, 3.0, and

Summary

Introduction

Plant factories with artificial lighting (PFALs) are considered a high-end agricultural model that has many advantages over traditional agriculture These include scheduled production, shorter production cycle, local production, high vegetable quality, etc. In PFALs, environmental conditions such as the nutrient solution (NS), light intensity, photoperiod, and temperature are controlled by the operator, who can enhance the yield and content of antioxidants in plants through environmental control. In countries such as Japan, China, America, etc., PFALs have been being used to produce leafy greens, herbs, medicinal plants, and other vegetables [1]. EC management is a common and important method widely used in hydroponic cultivation to effectively improve the yield and quality of vegetables [3–7]

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