Abstract
Soil nitrogen (N) is available to rice crops as either nitrate or ammonium, but only nitrate can be accrued in cells and so factors that influence its storage and remobilization are important for N use efficiency (NUE). The hypothesis that the ability of rice crops to remobilize N storage pools is an indicator of NUE was tested. When two commonly grown Chinese rice cultivars, Nong Ken (NK) and Yang Dao (YD), were compared in soil and hydroponics, YD had significantly greater NUE for biomass production. The ability of each cultivar to remobilize nitrate storage pools 24 h after N supply withdrawal was compared. Although microelectrode measurements of the epidermal sub-cellular nitrate pools in leaves and roots showed similar patterns of vacuolar remobilization in both cultivars, whole-tissue analysis showed very little depletion of storage pools after 24 h. However, leaf epidermal cell cytosolic nitrate activities were significantly higher in YD when compared with NK. Before N starvation and growing in 10 mM nitrate, the xylem nitrate activity in YD was lower than that of NK. After 24 h of N starvation the xylem nitrate had decreased more in YD than in NK. Tissue analysis of stems showed that YD had accumulated significantly more nitrate than NK, and the remobilization pattern suggested that this store is important for both cultivars. Changes in nitrate reductase activity (NRA) and expression were measured. Growing in 10 mM nitrate, NRA was undetectable in roots of both cultivars, and the leaf total NRA of equivalent leaves was similar in NK and YD. When the N supply was withdrawn, after 24 h NRA in NK was reduced to 80% but no decrease was found in YD. The proportion of NRA in an active form in YD was significantly higher than that in NK under both nitrate supply and deprivation conditions. Checking NR gene expression showed that leaf expression of OsNia1 was faster to respond to nitrate deprivation than OsNia2 in both cultivars. These measurements are discussed in relation to cultivar differences and physiological markers for NUE in rice.
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Claims 14
Claim · model-written summary
Yang Dao had significantly greater nitrogen use efficiency for biomass production than Nong Ken in soil and hydroponics.
- Taxon
- rice
Oryza sativat0 - Material
- Yang Dao (YD)e1
- Outcome
- NUE for biomass productione1
- Direction
- greatere1
- Comparator
- Nong Ken (NK)e1
- Setting
- soil and hydroponicse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“When two commonly grown Chinese rice cultivars, Nong Ken (NK) and Yang Dao (YD), were compared in soil and hydroponics, YD had significantly greater NUE for biomass production”
t0“two rice cultivars”
Claim · model-written summary
Epidermal sub-cellular nitrate pools in leaves and roots showed similar patterns of vacuolar remobilization in both rice cultivars.
- Taxon
- riceOryza sativat0
- Material
- both cultivarse2
- Organ / stage
- leaves and rootse2
- Outcome
- vacuolar remobilizatione2
- Direction
- no_changeinferrede2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Although microelectrode measurements of the epidermal sub-cellular nitrate pools in leaves and roots showed similar patterns of vacuolar remobilization in both cultivars”
t0“two rice cultivars”
Claim · model-written summary
Whole-tissue analysis showed very little depletion of storage pools after 24 h of N supply withdrawal.
- Taxon
- riceOryza sativat0
- Outcome
- depletion of storage poolse3
- Qualifier
- very littlee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“whole-tissue analysis showed very little depletion of storage pools after 24 h”
t0“two rice cultivars”
Claim · model-written summary
Leaf epidermal cell cytosolic nitrate activities were significantly higher in Yang Dao than in Nong Ken.
- Taxon
- riceOryza sativat0
- Material
- YDe4
- Organ / stage
- leaf epidermal celle4
- Outcome
- cytosolic nitrate activitiese4
- Direction
- highere4
- Comparator
- NKe4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“leaf epidermal cell cytosolic nitrate activities were significantly higher in YD when compared with NK”
t0“two rice cultivars”
Claim · model-written summary
Before N starvation in 10 mM nitrate, xylem nitrate activity in Yang Dao was lower than in Nong Ken.
- Taxon
- riceOryza sativat0
- Material
- YDe5
- Organ / stage
- xyleme5
- Treatment
- 10 mM nitratee5
- Outcome
- xylem nitrate activitye5
- Direction
- lowere5
- Comparator
- NKe5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Before N starvation and growing in 10 mM nitrate, the xylem nitrate activity in YD was lower than that of NK”
t0“two rice cultivars”
Claim · model-written summary
After 24 h of N starvation, xylem nitrate decreased more in Yang Dao than in Nong Ken.
- Taxon
- riceOryza sativat0
- Material
- YDe6
- Treatment
- N starvatione6
- Outcome
- xylem nitratee6
- Direction
- decreasede6
- Comparator
- NKe6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“After 24 h of N starvation the xylem nitrate had decreased more in YD than in NK”
t0“two rice cultivars”
Claim · model-written summary
Yang Dao accumulated significantly more nitrate in stems than Nong Ken.
- Taxon
- riceOryza sativat0
- Material
- YDe7
- Organ / stage
- stemse7
- Outcome
- nitratee7
- Direction
- moree7
- Comparator
- NKe7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“Tissue analysis of stems showed that YD had accumulated significantly more nitrate than NK”
t0“two rice cultivars”
Claim · model-written summary
The remobilization pattern suggests that the nitrate store is important for both rice cultivars.
- Taxon
- riceOryza sativat0
- Outcome
- remobilizatione1
- Qualifier
- this store is important for both cultivarse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“the remobilization pattern suggested that this store is important for both cultivars”
t0“two rice cultivars”
Claim · model-written summary
After 24 h of N supply withdrawal, nitrate reductase activity in Nong Ken was reduced to 80%.
- Taxon
- riceOryza sativat0
- Material
- NKe1
- Treatment
- the N supply was withdrawne1
- Outcome
- NRAe1
- Direction
- reducede1
- Value
- 80%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“When the N supply was withdrawn, after 24 h NRA in NK was reduced to 80% but no decrease was found in YD”
t0“two rice cultivars”
Claim · model-written summary
After 24 h of N supply withdrawal, nitrate reductase activity in Yang Dao showed no decrease.
- Taxon
- riceOryza sativat0
- Material
- YDe1
- Treatment
- the N supply was withdrawne1
- Outcome
- NRAe1
- Direction
- no decreasee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“When the N supply was withdrawn, after 24 h NRA in NK was reduced to 80% but no decrease was found in YD”
t0“two rice cultivars”
Claim · model-written summary
Growing in 10 mM nitrate, nitrate reductase activity was undetectable in roots of both rice cultivars.
- Taxon
- riceOryza sativat0
- Organ / stage
- rootse1
- Treatment
- 10 mM nitratee1
- Outcome
- NRAe1
- Qualifier
- undetectablee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Growing in 10 mM nitrate, NRA was undetectable in roots of both cultivars”
t0“two rice cultivars”
Claim · model-written summary
Leaf total nitrate reductase activity of equivalent leaves was similar in Nong Ken and Yang Dao.
- Taxon
- riceOryza sativat0
- Material
- NK and YDe1
- Outcome
- leaf total NRA of equivalent leavese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“the leaf total NRA of equivalent leaves was similar in NK and YD”
t0“two rice cultivars”
Claim · model-written summary
The proportion of active-form nitrate reductase was significantly higher in Yang Dao than in Nong Ken under nitrate supply and deprivation.
- Taxon
- riceOryza sativat0
- Material
- YDe1
- Treatment
- nitrate supply and deprivatione1
- Outcome
- proportion of NRA in an active forme1
- Direction
- highere1
- Comparator
- NKe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The proportion of NRA in an active form in YD was significantly higher than that in NK under both nitrate supply and deprivation conditions”
t0“two rice cultivars”
Claim · model-written summary
Leaf OsNia1 expression responded faster to nitrate deprivation than OsNia2 in both rice cultivars.
- Taxon
- riceOryza sativat0
- Material
- both cultivarse1
- Organ / stage
- leafe1
- Treatment
- nitrate deprivatione1
- Gene
- OsNia1e1
- Outcome
- leaf expressione1
- Direction
- fastere1
- Comparator
- OsNia2e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“leaf expression of OsNia1 was faster to respond to nitrate deprivation than OsNia2 in both cultivars”
t0“two rice cultivars”
The same questions in other papers
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