Agricultural experiment Station, North Carolina State University, Raleigh.
Planta. 1970 Mar;95(1):36-44. doi: 10.1007/BF00431119.
Intact wheat seedlings cultured in high nitrate solutions (high-NO 3 (-) cultures) reduced NO 3 (-) when placed for 24 hr in dilute CaSO4 solutions although they leaked NO 3 (-) back to solution during this period. Most of the reduction seemed to occur in shoots since in parallel experiments detached shoots reduced nearly as much of the previously absorbed NO 3 (-) as intact cultures. Detached roots leaked greater quantities of NO 3 (-) back to solution than did intact cultures, and failed to reduce any of their previously absorbed NO 3 (-) during the experimental period. Seedlings of identical age cultured without a nitrogen source and rich in carbohydrate reserves (low-N cultures) rapidly absorbed NO 3 (-) from dilute Ca(NO3)2 solutions and reduced 80% of that absorbed. Detached low-N roots also absorbed NO 3 (-) and reduced 40% of that absorbed. Total NO 3 (-) reduction by intact low-N cultures over the 24-hr period was comparable to that of high-NO 3 (-) cultures in spite of the fact that in vitro nitrate reductase activity of the former did not reach the levels found initially or at the end of the period in the latter, and that the total NO 3 (-) absorbed by low-N cultures was less than that initially present in high-NO 3 (-) cultures.
在高硝酸盐溶液（高硝酸盐培养）中培养的完整小麦幼苗在将其置于稀 CaSO4 溶液中 24 小时时会减少硝酸盐，尽管在此期间它们会将硝酸盐泄漏回溶液中。大部分还原似乎发生在地上部分，因为在平行实验中，离体地上部分还原了与完整培养物几乎相同数量的先前吸收的硝酸盐。离体根漏回溶液的硝酸盐数量大于完整培养物，并且在实验期间未能还原其先前吸收的任何硝酸盐。在没有氮源且富含碳水化合物储备的相同年龄的幼苗（低氮培养物）从稀 Ca(NO3)2 溶液中迅速吸收硝酸盐，并还原了 80%的吸收量。离体低氮根也吸收硝酸盐，并还原了 40%的吸收量。尽管完整的低氮培养物的体外硝酸还原酶活性在整个 24 小时期间都没有达到后者的初始水平或末期水平，并且低氮培养物吸收的总硝酸盐量也少于高硝酸盐培养物中最初存在的硝酸盐量，但完整的低氮培养物在 24 小时期间的总硝酸盐还原量与高硝酸盐培养物相当。
