Abstract
Tea plant is famed in humid and sub-humid of tropical regions, sub-tropical regions, and is a leaf-harvested crop. Nitrogen is the most important nutrient for increasing quality of tea leaves. Therefore, large amounts of nitrogen fertilizer are increasingly applied by tea farmers. Appropriate application of nitrogen fertilizer aroused people’s concern. This research of physiological response to N deficiency stress will be helpful for appropriate application of nitrogen fertilizer for tea farmers and elucidate a mechanistic basis for the reductions in carbon dioxide (CO2) assimilation. To elucidate a mechanistic basis for the reductions in carbon dioxide (CO2) assimilation under nitrogen (N) deficiency tea leaves, changes in chlorophyll (Chl), carbohydrates, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and chlorophyll fluorescence transient were examined together with six N treatment (0, 50, 100, 300, 1200 or 6000 μM N). Root, stem and leaves dry weight (DW) increased as N supply increased from 0 to 300 μM, then remained unchanged. The reductions in CO2 assimilation of N-deficient leaves paralleled with high intercellular CO2 concentration. Rubisco activity, protein and Chl content increased linearly or curvilinearly over the range of leaf N content examined except unchanged as leaf N from 2.15 to 2.79 g m−2. Chlorophyll fluorescence transient from N-deficient leaves displayed a depression at the P-step, accompanied by a new step at about 150 μs (L-step). Fv/Fm, REo/ETo, ETo/ABS, Sm, ETo/CSo, PIabs, PItot, abs, were decreased in N-deficient leaves but increased DIo/CSo, DIo/RC and DIo/ABS. Regressive analysis showed that CO2 assimilation decreased linearly or curvilinearly with decreasing initial rubisco, PIabs and Leaf Chl, respectively. Therefore, we concluded the decreased photosynthetic electron transport capacity, leaf chl content and initial rubisco activity are probably the main factors contributing to decreased CO2 assimilation under N deficiency. The decreased photosynthetic electron transport capacity, leaf Chl content and initial rubisco activity are probably the main factors contributing to decreased CO2 assimilation under N deficiency.
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Claims 11
Claim · model-written summary
Root, stem and leaf dry weight rose with N supply from 0 to 300 μM.
- Taxon
- Tea plante1
- Treatment
- N supply increased from 0 to 300 μMe0
- Outcome
- Root, stem and leaves dry weight (DW)e0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“Root, stem and leaves dry weight (DW) increased as N supply increased from 0 to 300 μM”
e1“Tea plant”
Claim · model-written summary
Dry weight remained unchanged above 300 μM N.
Verbatim
e0“then remained unchanged”
e1“N supply increased from 0 to 300 μM”
e2“Tea plant”
e3“dry weight (DW)”
Claim · model-written summary
N-deficient leaves had reduced CO2 assimilation alongside high intercellular CO2.
Verbatim
e0“The reductions in CO2 assimilation of N-deficient leaves paralleled with high intercellular CO2 concentration”
e1“Tea plant”
Claim · model-written summary
Rubisco activity, protein and chlorophyll content generally increased with leaf N content.
Verbatim
e0“Rubisco activity, protein and Chl content increased linearly or curvilinearly over the range of leaf N content examined except unchanged as leaf N from 2.15 to 2.79 g m−2”
e1“Tea plant”
Claim · model-written summary
N-deficient leaves showed a depressed fluorescence P-step and new L-step.
Verbatim
e0“Chlorophyll fluorescence transient from N-deficient leaves displayed a depression at the P-step, accompanied by a new step at about 150 μs (L-step)”
e1“Tea plant”
Claim · model-written summary
Several electron transport parameters decreased in N-deficient leaves.
- Taxon
- Tea plante1
- Treatment
- N-deficiente0
- Outcome
- Fv/Fm, REo/ETo, ETo/ABS, Sm, ETo/CSo, PIabs, PItot, abse0
- Direction
- decreasede0
Not reportedComparator
Verbatim
e0“Fv/Fm, REo/ETo, ETo/ABS, Sm, ETo/CSo, PIabs, PItot, abs, were decreased in N-deficient leaves”
e1“Tea plant”
Claim · model-written summary
Energy dissipation parameters increased in N-deficient leaves.
- Taxon
- Tea plante2
- Treatment
- N-deficient leavese1
- Outcome
- DIo/CSo, DIo/RC and DIo/ABSe0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“increased DIo/CSo, DIo/RC and DIo/ABS”
e1“were decreased in N-deficient leaves but increased”
e2“Tea plant”
Claim · model-written summary
CO2 assimilation decreased with decreasing initial Rubisco.
Verbatim
e0“CO2 assimilation decreased linearly or curvilinearly with decreasing initial rubisco, PIabs and Leaf Chl”
e1“Tea plant”
Claim · model-written summary
CO2 assimilation decreased with decreasing PIabs.
Verbatim
e0“CO2 assimilation decreased linearly or curvilinearly with decreasing initial rubisco, PIabs and Leaf Chl”
e1“Tea plant”
Claim · model-written summary
CO2 assimilation decreased with decreasing leaf chlorophyll.
Verbatim
e0“CO2 assimilation decreased linearly or curvilinearly with decreasing initial rubisco, PIabs and Leaf Chl”
e1“Tea plant”
Claim · model-written summary
The authors attributed diminished CO2 assimilation to electron transport capacity, chlorophyll and Rubisco activity.
Verbatim
e0“decreased photosynthetic electron transport capacity, leaf chl content and initial rubisco activity are probably the main factors contributing to decreased CO2 assimilation under N deficiency”
e1“Tea plant”
The same questions in other papers
nitrogen · growth · Camellia sinensis (black tea)Positive and negative results
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See all 11 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.