Does nitrate accumulate in strawberry leaves as nutrient nitrate concentration increases?

Strawberry plants have shallow roots and need efficient nitrogen fertilization, as nitrogen leaches into the drainage and underground water and is a threat to the environment. Understanding the nitrogen requirements of strawberry plants will help us to estimate the needed nitrogen fertilization and avoid excessive fertilization. This experiment was conducted to study the relationship between nitrate concentration of strawberry leaves and different nitrate concentrations in nutrient solutions. The experiment was a complete randomized design with 5 nitrate concentrations in nutrient solutions (0.1, 1, 2, 3, and 4 mM) and 5 replicates. The results showed that the effect of nitrate concentrations was not effective on leaf nitrate concentrations, but at 0.1 mM nitrate concentration more nitrate was accumulated in the leaves than 1 mM. In higher concentrations (3-4 mM) higher nitrate accumulation was observed in leaves. The relationship between nitrate concentration in nutrient solutions and leaf nitrate was studied too. A linear, exponential, logarithmic, 2^nd and 3^rd order polynomial regression types was fitted to the data. The R squared values of the regressions were significant (pKLEINERDAN5%). The highest R² belonged to 3^rd order polynomial regression (R²=0.93).