Study on Difference in Nitrate Accumulation Characteristic between Two Spinach Varieties

Solution culture experiments with two varieties of spinach were conducted to study the differences on growth, nitrogen absorption, nitrate accumulation and reduction. The results indicated that, at the later growth period, the weight of Japanese spinach variety was larger than that of Ningxia spinach variety and accumulated nitrate amounts of J. sp. was less than that of N. sp. in the late growth stage. Under the condition of solution culture with two nitrogen resource after solution culture lacking nitrogen, J. sp. was more favorable to NH4+-N and it's nitrogen absorbed was less than N. sp., nitrate relatively reduction ability of J. sp. also was greater than that of N. sp. When the plants were cultured with nutrition solution only containing NH4+-N resource after culture with high concentration of NO3--N, the nitrate reduction ability of N. sp. was larger than that of J. sp. because of more NH4+-N absorbed by J. sp. for metabolism.