Studies of the regulation of nitrate influx by barley seedlings using sup 13 NO sub 3 sup minus 1. [Hordeum vulgare L]

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.90.3.806· OSTI ID:6968331

Siddiqi, M Y; Glass, A D.M.; Ruth, T J; Fernando, M

Using {sup 13}NO{sub 3}{sup {minus}}, effects of various NO{sub 3}{sup {minus}} pretreatments upon NO{sub 3}{sup {minus}} influx were studied in intact roots of barley (Hordeum vulgare L. cv Klondike). Prior exposure of roots to NO{sub 3}{sup {minus}} increased NO{sub 3}{sup {minus}} influx and net NO{sub 3}{sup {minus}} uptake. This induction of NO{sub 3}{sup {minus}} uptake was dependent both on time and external NO{sub 3}{sup {minus}} concentration ((NO{sub 3}{sup {minus}})). During induction influx was positively correlated with root (NO{sub 3}{sup {minus}}). In the postinduction period, however, NO{sub 3}{sup {minus}} influx declined as root (NO{sub 3}{sup {minus}}) increased. It is suggested that induction and negative feedback regulation are independent processes: induction appears to depend upon some critical cytoplasmic (NO{sub 3}{sup {minus}}); removal of external NO{sub 3}{sup {minus}} caused a reduction of {sup 13}NO{sub 3}{sup {minus}} influx even though mean root (NO{sub 3}{sup {minus}}) remained high. It is proposed that cytoplasmic (NO{sub 3}{sup {minus}}) is depleted rapidly under these conditions resulting in deinduction of the NO{sub 3}{sup {minus}} transport system. Beyond 50 micromoles per gram (NO{sub 3}{sup {minus}}), {sup 13}NO{sub 3}{sup {minus}} influx was negatively correlated with root (NO{sub 3}{sup {minus}}). However, it is unclear whether root (NO{sub 3}{sup {minus}}) per se or some product(s) of NO{sub 3}{sup {minus}} assimilation are responsible for the negative feedback effects.

• OSTI ID: 6968331
• Journal Information: Plant Physiology; (USA), Vol. 90:3; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
BARLEY
METABOLISM
NITRATES
UPTAKE
NITROGEN 13
NITROGEN COMPOUNDS
ROOTS
SEEDLINGS
TRACER TECHNIQUES
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CEREALS
ELECTRON CAPTURE RADIOISOTOPES
GRASS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LILIOPSIDA
MAGNOLIOPHYTA
MINUTES LIVING RADIOISOTOPES
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
OXYGEN COMPOUNDS
PLANTS
RADIOISOTOPES
551001* - Physiological Systems- Tracer Techniques