Abstract
Previous research indicates that nitrate accumulation in plants changed with plant growth,but mechanisms behind those changes are unknown.Understanding these mechanisms will benefit adopting appropriate strategies to decrease the nitrate content in plants since high nitrate accumulation in leafy vegetables is potentially toxic to human health.A pot experiment was carried out to investigate the dry weight,water content,and nitrate-N concentrations of petioles and leaf blades,and in vivo and in vitro nitrate reductase activity(NRA) in leaf blades of two spinach cultivars at different growth stages.The objective was to study the dynamic changes of nitrate-N concentrations and NRA of two spinach cultivars,and their relations to plant growth.The results showed that the dry weights and water contents of petioles,leaf blades,and shoot for both cultivars increased with the increase of plant biomass and then declined with the decrease of plant growth.However,the nitrate-N concentrations of both cultivars decreased with plant growth,and the decrease for cultivar S9 with lower nitrate-N concentration was more significantly than that for cultivar S4 with higher nitrate-N concentration.During the early growth stage,in vivo and in vitro NRA increased with plant growth,and these for cultivar S4 increased by 379% and 199% which were significantly higher than that for cultivar S9,but they were decreased for cultivar S4 and increased for cultivar S9 at later growth stage.The increase of dry weight and water content,nitrate-N concentrations,in vivo and in vitro NRA of cultivar S4 were significantly higher,but the ratio of in vivo /in vitro NRA was lower than those of cultivar S9 on days 40 and 52 after germination.These differences between spinach cultivars were not significant at later growth stage.This indicated that the nitrate decrease of cultivar S4 was more slowly than that of cultivar S9 should be due to its lower ratio of in vivo /in vitro NRA,and this hypothesis was proved by the fact that the nitrate-N concentration of cultivar S4 decreased significantly with the increase of in vivo /in vitro NRA ratio at late stage.This suggested that the variations of nitrate-N concentration for both cultivars be closely related to the ratio of in vivo /in vitro NRA at different growth stages.
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Claims 9
Claim · model-written summary
Dry weights and water contents of petioles, leaf blades and shoot increased with plant biomass and then declined as growth decreased.
- Taxon
- Spinach
Spinacia oleraceat0 - Material
- two spinach cultivarse0
- Organ / stage
- petioles,leaf blades,and shoote1
- Outcome
- dry weights and water contentse1
- Direction
- increasede1
- Qualifier
- then declined with the decrease of plant growthe1
- Setting
- pot experimente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nitrate Accumulation and Reduction in Spinach and Their Relations to Plant Growth”
e0“A pot experiment was carried out to investigate the dry weight,water content,and nitrate-N concentrations of petioles and leaf blades,and in vivo and in vitro nitrate reductase activity(NRA) in leaf blades of two spinach cultivars at different growth stages”
e1“The results showed that the dry weights and water contents of petioles,leaf blades,and shoot for both cultivars increased with the increase of plant biomass and then declined with the decrease of plant growth”
Claim · model-written summary
Nitrate-N concentrations of both spinach cultivars decreased with plant growth.
- Taxon
- SpinachSpinacia oleraceat0
- Material
- two spinach cultivarse0
- Outcome
- nitrate-N concentrationse2
- Direction
- decreasede2
- Qualifier
- with plant growthe2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nitrate Accumulation and Reduction in Spinach and Their Relations to Plant Growth”
e0“A pot experiment was carried out to investigate the dry weight,water content,and nitrate-N concentrations of petioles and leaf blades,and in vivo and in vitro nitrate reductase activity(NRA) in leaf blades of two spinach cultivars at different growth stages”
e2“However,the nitrate-N concentrations of both cultivars decreased with plant growth,and the decrease for cultivar S9 with lower nitrate-N concentration was more significantly than that for cultivar S4 with higher nitrate-N concentration”
Claim · model-written summary
Nitrate-N concentration decreased more significantly in cultivar S9 than in cultivar S4.
- Taxon
- SpinachSpinacia oleraceat0
- Material
- cultivar S9e2
- Outcome
- nitrate-N concentrationse2
- Direction
- decreasee2
- Qualifier
- more significantlye2
- Comparator
- cultivar S4e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nitrate Accumulation and Reduction in Spinach and Their Relations to Plant Growth”
e2“However,the nitrate-N concentrations of both cultivars decreased with plant growth,and the decrease for cultivar S9 with lower nitrate-N concentration was more significantly than that for cultivar S4 with higher nitrate-N concentration”
Claim · model-written summary
In vivo and in vitro nitrate reductase activity increased with plant growth during the early growth stage.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- in vivo and in vitro NRAe3
- Direction
- increasede3
- Qualifier
- During the early growth stagee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nitrate Accumulation and Reduction in Spinach and Their Relations to Plant Growth”
e3“During the early growth stage,in vivo and in vitro NRA increased with plant growth,and these for cultivar S4 increased by 379% and 199% which were significantly higher than that for cultivar S9”
Claim · model-written summary
Cultivar S4 showed NRA increases of 379% and 199% in the early growth stage, significantly higher than cultivar S9.
- Taxon
- SpinachSpinacia oleraceat0
- Material
- cultivar S4e3
- Outcome
- in vivo and in vitro NRAe3
- Direction
- increasede3
- Value
- 379% and 199%e3
- Comparator
- cultivar S9e3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nitrate Accumulation and Reduction in Spinach and Their Relations to Plant Growth”
e3“During the early growth stage,in vivo and in vitro NRA increased with plant growth,and these for cultivar S4 increased by 379% and 199% which were significantly higher than that for cultivar S9”
Claim · model-written summary
The ratio of in vivo to in vitro NRA was lower in cultivar S4 than in cultivar S9 on days 40 and 52 after germination.
- Taxon
- SpinachSpinacia oleraceat0
- Material
- cultivar S4e4
- Outcome
- the ratio of in vivo /in vitro NRAe4
- Direction
- lowere4
- Qualifier
- on days 40 and 52 after germinatione4
- Comparator
- cultivar S9e4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nitrate Accumulation and Reduction in Spinach and Their Relations to Plant Growth”
e4“The increase of dry weight and water content,nitrate-N concentrations,in vivo and in vitro NRA of cultivar S4 were significantly higher,but the ratio of in vivo /in vitro NRA was lower than those of cultivar S9 on days 40 and 52 after germination”
Claim · model-written summary
Differences between the two spinach cultivars were not significant at the later growth stage.
- Taxon
- SpinachSpinacia oleraceat0
- Outcome
- differences between spinach cultivarse5
- Qualifier
- at later growth stagee5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nitrate Accumulation and Reduction in Spinach and Their Relations to Plant Growth”
e5“These differences between spinach cultivars were not significant at later growth stage”
Claim · model-written summary
Nitrate-N concentration of cultivar S4 decreased significantly as the in vivo / in vitro NRA ratio increased at the late stage.
- Taxon
- SpinachSpinacia oleraceat0
- Material
- cultivar S4e6
- Outcome
- nitrate-N concentratione6
- Direction
- decreasede6
- Qualifier
- with the increase of in vivo /in vitro NRA ratio at late stagee6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nitrate Accumulation and Reduction in Spinach and Their Relations to Plant Growth”
e6“the nitrate-N concentration of cultivar S4 decreased significantly with the increase of in vivo /in vitro NRA ratio at late stage”
Claim · model-written summary
Variations of nitrate-N concentration in both cultivars were closely related to the in vivo / in vitro NRA ratio at different growth stages.
- Taxon
- SpinachSpinacia oleraceat0
- Material
- both cultivarse7
- Outcome
- variations of nitrate-N concentratione7
- Qualifier
- closely related to the ratio of in vivo /in vitro NRA at different growth stagese7
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nitrate Accumulation and Reduction in Spinach and Their Relations to Plant Growth”
e7“the variations of nitrate-N concentration for both cultivars be closely related to the ratio of in vivo /in vitro NRA at different growth stages”