Abstract
In barley (Hordeum vulgare L.) seedlings, the rate of root growth, osmotic pressure (Π), hydraulic conductance (L p), and longitudinal (δl) and transverse (δD/D) extensibility of root cells were measured. The seedlings were grown on Knop solution with nitrate or without nitrate with addition of 5–10 mM NH 4 + or 0.5–1.0 mM glutamate. Root growth retardation on the 1st–4th days of exposure to NH 4 + was determined by a decrease in δl in the zone of elongation, whereas root thickening was evidently related to an increase in Π. Biphasic dynamics of δl in the presence of NH 4 + was imitated by medium acidification near the root surface to pH 3.7, which confirms a conclusion, we have done earlier, about a non-monotonous pH-dependence of longitudinal extensibility. Root growth retardation during the first day of exposure to Glu was also determined by a decrease in the δl, which was, however, accompanied by an increase in the δD/D and L p. Fast Glu-induced changes of measured root parameters were imitated by root exposure to oryzalin, ionomycin, and inhibitors of the H+-pump. It was supposed that a decrease in δl in the presence of NH 4 + and Glu was related to cortical microtubule disorganization with the involvement of cytosolic calcium Ca cyt 2+ . A decrease in the δD/D and L p in the presence of NH 4 + was related to apoplast acidification and a high activity of the plasmalemmal H+-pump. An increase in the δD/D and L p in the presence of Glu indicates the inhibition of the plasmalemmal H+-pump. On the 2nd–4th days of exposure to Glu, root growth ceased, as distinct from treatment with NH 4 + . This complete root growth inhibition by Glu was possibly related to a rapid uptake of Ca2+ through Glu-sensitive Ca2+-channels, Ca2+-dependent inhibition of the plasmalemmal H+-pump, and a decrease in mitotic activity.
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Claims 14
Claim · model-written summary
Ammonium retarded root growth during days 1–4 through reduced longitudinal extensibility.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaret0 - Treatment
- NH 4 +e0
- Outcome
- Root growth retardatione0
- Qualifier
- decrease in δle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Root growth retardation on the 1st–4th days of exposure to NH 4 + was determined by a decrease in δl in the zone of elongation”
t0“barley”
Claim · model-written summary
Root thickening under ammonium was related to increased osmotic pressure.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- roote0
- Outcome
- root thickeninge0
- Direction
- thickeninge0
- Qualifier
- increase in Πe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“root thickening was evidently related to an increase in Π”
t0“barley”
Claim · model-written summary
Medium acidification to pH 3.7 imitated the biphasic longitudinal extensibility response to ammonium.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- medium acidification near the root surface to pH 3.7e0
- Outcome
- Biphasic dynamics of δle0
- Comparator
- NH 4 +e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biphasic dynamics of δl in the presence of NH 4 + was imitated by medium acidification near the root surface to pH 3.7”
t0“barley”
Claim · model-written summary
Glutamate retarded first-day root growth through decreased longitudinal extensibility.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- Glue0
- Outcome
- Root growth retardatione0
- Qualifier
- decrease in the δle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root growth retardation during the first day of exposure to Glu was also determined by a decrease in the δl”
t0“barley”
Claim · model-written summary
Glutamate increased transverse root-cell extensibility.
- Taxon
- barleyHordeum vulgaret0
- Outcome
- δD/De0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“accompanied by an increase in the δD/D and L p”
t0“barley”
Claim · model-written summary
Glutamate increased root hydraulic conductance.
- Taxon
- barleyHordeum vulgaret0
- Outcome
- L pe0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“accompanied by an increase in the δD/D and L p”
t0“barley”
Claim · model-written summary
Oryzalin exposure imitated rapid glutamate-induced root responses.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- oryzaline0
- Outcome
- Fast Glu-induced changes of measured root parameterse0
- Comparator
- Glue0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fast Glu-induced changes of measured root parameters were imitated by root exposure to oryzalin, ionomycin, and inhibitors of the H+-pump”
t0“barley”
Claim · model-written summary
Ionomycin exposure imitated rapid glutamate-induced root responses.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- ionomycine0
- Outcome
- Fast Glu-induced changes of measured root parameterse0
- Comparator
- Glue0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fast Glu-induced changes of measured root parameters were imitated by root exposure to oryzalin, ionomycin, and inhibitors of the H+-pump”
t0“barley”
Claim · model-written summary
H+-pump inhibitors imitated rapid glutamate-induced root responses.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- inhibitors of the H+-pumpe0
- Outcome
- Fast Glu-induced changes of measured root parameterse0
- Comparator
- Glue0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fast Glu-induced changes of measured root parameters were imitated by root exposure to oryzalin, ionomycin, and inhibitors of the H+-pump”
t0“barley”
Claim · model-written summary
Cortical microtubule disorganization with cytosolic calcium involvement was proposed to explain decreased longitudinal extensibility under ammonium and glutamate.
- Taxon
- barleyHordeum vulgaret0
- Outcome
- decrease in δle0
- Qualifier
- cortical microtubule disorganizatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a decrease in δl in the presence of NH 4 + and Glu was related to cortical microtubule disorganization with the involvement of cytosolic calcium Ca cyt 2+”
t0“barley”
Claim · model-written summary
Under ammonium, decreased transverse extensibility and hydraulic conductance were related to apoplast acidification and high H+-pump activity.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- NH 4 +e0
- Outcome
- decrease in the δD/D and L pe0
- Qualifier
- apoplast acidificatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A decrease in the δD/D and L p in the presence of NH 4 + was related to apoplast acidification and a high activity of the plasmalemmal H+-pump”
t0“barley”
Claim · model-written summary
Under glutamate, increased transverse extensibility and hydraulic conductance indicated H+-pump inhibition.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- Glue0
- Outcome
- increase in the δD/D and L pe0
- Qualifier
- inhibition of the plasmalemmal H+-pumpe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“An increase in the δD/D and L p in the presence of Glu indicates the inhibition of the plasmalemmal H+-pump”
t0“barley”
Claim · model-written summary
Glutamate caused root growth to cease on days 2–4, unlike ammonium.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On the 2nd–4th days of exposure to Glu, root growth ceased, as distinct from treatment with NH 4 +”
t0“barley”
Claim · model-written summary
Complete glutamate inhibition of root growth was possibly related to calcium uptake, H+-pump inhibition and reduced mitosis.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- Glue0
- Outcome
- complete root growth inhibitione0
- Qualifier
- rapid uptake of Ca2+e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This complete root growth inhibition by Glu was possibly related to a rapid uptake of Ca2+ through Glu-sensitive Ca2+-channels, Ca2+-dependent inhibition of the plasmalemmal H+-pump, and a decrease in mitotic activity”
t0“barley”