Nitrate reductase activity and uptake of nitrate and oxygen as affected by nitrate supply to detached maize organs
Year: 1997
Type: article
Abstract: Supply of 1, 2, 5, 10 or 20 mM nitrate to detached roots, scutella or shoots from 5- to 6-d-old Zea mays L. seedlings increased in vitro nitrate reductase (NR) activity in all the organs and NADPH specific NR (NADPH:NR) activity in roots and scutella but not in the shoots. Usually 2 to 5 mM nitrate supported maximum enzyme activity, the higher concentration did not increase it further. The protein content in the roots, scutella and shoots increased up to 5, 2 and 20 mM medium nitrate, respectively. Nitrate uptake also increased with increasing nitrate concentration in roots and shoots, but it increased only slightly in the scutella. In both roots and scutella, methionine sulfoximine had no effect, while cycloheximide and tungstate abolished nitrate induced NADH:NR activity completely and NADPH:NR partially. Methionine sulfoximine increased nitrate uptake by roots and scutella slightly, but other inhibitors had no effect. The depletion of dissolved oxygen from the medium was lower in the presence of nitrate than in its absence or in the presence of ammonium, especially in the scutella.
Source: Biologia Plantarum
Authors: N. Shankar, H.S. Srivastava
Institution: M.J.P. Rohilkhand University
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: bronze
OpenAlex ID: W1802676