Search Results
Nitrate (NO3) was supplied at 100, 200, 400, and 800 μm in nutrient solution to 3-week-old tomato seedlings grown hydroponicly, and day and night concentrations of N and C metabolites were measured. Tissue [NO,] at the end of the night was greater than at the end of the day, especially for leaves. Leaf tissue [NO3] was about 350 μmol·g-1 dry weight at night, 3 times as high as that during the day. Generally, root and stem tissue [NO,] was similar and higher than that of leaves and increased as medium [NO,] increased. The difference was greater at night than during the day. During the day, total free amino acid concentration was the greatest for roots and the least for stem. Generally, root tissue had higher total free sugar concentration than leaf and stem tissues during the day. Fructose concentration was lower at night than during the day for all parts of the plants, especially for roots. At night, NO3 accumulated in plant tissues, especially in leaves, and was not incorporated into amino acids, perhaps due to the lack of energy and reductant.