Salinity from NaCl changes the nutrient and polyphenolic composition of basil leaves

Authors: Scagel, Carolyn; Lee, Jungmin; Mitchell, Jesse

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2018
Publication Date: 1/15/2019
Citation: Scagel, C.F., Lee, J., Mitchell, J.N. 2019. Salinity from NaCl changes the nutrient and polyphenolic composition of basil leaves. Industrial Crops and Products. 127:119-128. https://doi.org/10.1016/j.indcrop.2018.10.048.
DOI: https://doi.org/10.1016/j.indcrop.2018.10.048

Interpretive Summary: Yield and composition of basil were assessed when grown hydroponically with different levels of salinity from sodium chloride (NaCl). Hydroponic solutions with salinity as high as 10 dS/m had no impact on leaf biomass after 71 d. Effects of salinity on leaf polyphenolic profiles depended on the level of salinity and cultivar. Salinity altered leaf composition at lower salinity levels than those that influenced biomass yield. Decreasing availability and rising costs of high quality water for irrigation results in more frequent use of saline water sources in many crop production systems. Our data suggest that water sources with salinity of <5 dS/m can be used to hydroponically grow basil with little effect on leaf polyphenolics.

Technical Abstract: Decreasing availability and rising costs of high quality water for irrigation results in more frequent use of saline water sources in many crop production systems. The effects of salinity on biomass yield has been the focus of most salinity studies with basil, and a few studies have reported how salinity influences basil polyphenolic composition. Two basil cultivars [Ocimum basilicum ‘Sweet Broadleaf’ (SB) and ‘Siam Queen’ (SQ)] were grown hydroponically for 71 d with four different levels of NaCl (no NaCl, Low, Moderate, and High) to determine whether the phenolic composition of leaves is altered by salinity. Salinity in the hydroponic solution reached as high as 20 dS m-1 at the highest NaCl level. Salinity had no influence on leaf color or plant mortality and minimal leaf necrosis occurred during the experiment. Compared to controls, NaCl decreased leaf biomass only at the highest salinity level. Salinity increased K accumulation in leaves, and plants generally excluded Na from leaves except at the highest NaCl level. Levels of salinity that altered basil leaf polyphenolic and nutrient composition were lower than those that influenced yield (leaf biomass). In both cultivars, salinity increased leaf accumulation of certain caffeic acid derivatives, caftaric acid, cinnamyl malic acid, and feruloyl tartaric acid and decreased production of chicoric acid. In SB, salinity increased leaf accumulation of the two of the major polyphenolics in basil leaves, quercetin-rutinoside and rosmarinic acid. In contrast, salinity decreased accumulation of rosmarinic acid in SQ leaves. Effects of salinity on leaf accumulation of elements other than Na, Cl, K, and Mg, were not directly related to effects of salinity on polyphenolics. Salinity levels that do not influence biomass yield in basil may negatively impact yield of certain polyphenolics important to product quality.