Effects of Nutrient and Water Supply During Fruit Development on Metabolite Composition in Tomato Fruits (Solanum lycopersicum L.) Grown in Magnesium Excess Soils.

Yangmin X Kim,Eun Sung Jung,Min Cheol Kwon,Jwakyung Sung,Seulbi Lee,Choong Hwan Lee

doi:10.3389/fpls.2020.562399

Yangmin X Kim, Eun Sung Jung + Show 4 more

Open Access

https://doi.org/10.3389/fpls.2020.562399

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Abstract

Tomato cultivation in the greenhouse or field may experience high surplus salts, including magnesium (Mg2+), which may result in differences in the growth and metabolite composition of fruits. This study hypothesized that decreasing the supply of nutrients and/or water would enhance tomato fruit quality in soils with excess Mg2+ that are frequently encountered in the field and aimed to find better supply conditions. For tomato plants cultivated in plastic pots using a plastic film house soil, the fertilizer supply varied in either the nitrogen (N) or potassium (K) concentration, which were either 0.1 (lowest) or 0.75 times (lower) than the standard fertilizer concentrations. Water was supplied either at 30 (sufficient) or 80 kPa (limited) of the soil water potential. Lycopene content on a dry-weight basis (mg/kg) was enhanced by the combination of lowest N supply and sufficient water supply. However, this enhancement was not occurred by the combination of the lowest N supply and limited water supply. Sugars and organic acids were decreased by limiting the water supply. Therefore, we carefully suggest that an adjustment of nitrogen with sufficient watering could be one of strategies to enhance fruit quality in excess Mg2+ soils.

Highlights

There is worldwide concern about soil salinization reaching 20% of irrigated land, which would cause a reduction in crop growth (Adams et al, 2019)
Leaf SPAD values were higher under limited water supply conditions than under sufficient irrigation, and it is speculated that plant growth was slowed by the water limitation, resulting in higher SPAD values
The symptoms in the leaves under N0.75, N0.1, K0.75, and K0.1 supplies were suppressed under limited water supply conditions compared to sufficient water, and this indicates that leaves experienced less nutrient deficiency under limited water than sufficient water condition

Summary

Introduction

There is worldwide concern about soil salinization reaching 20% of irrigated land, which would cause a reduction in crop growth (Adams et al, 2019). The greenhouse cultivation of tomatoes (Solanum lycopersicum L.), including in plastic film houses, involves the application of an extensive amount of fertilizers and produces an accumulation of surplus salts in soil (e.g., Mg2+, Ca2+, Na+, SO42-, and Cl-). The combination of reduced water supply and high NPK fertilizer concentrations enhanced tomato fruit quality by increasing lycopene, organic acid, and soluble sugar content (Wang and Xing, 2017). The combined effects of nitrogen fertilization and water have been investigated for soluble sugar, vitamin C, and free amino acid contents, in tomato fruits and in cucumber, and it was demonstrated that fruit quality increased under low irrigation conditions and a medium level of N application (Zhang et al, 2011). Controlling the nutrient and water supply is applicable for the purpose of enhancing fruit quality

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