Abstract
Mustard (Brassica juncea L.) is characterized by a large number of leaves in the lower layers. These leaves are poorly illuminated, remain below the light compensation point and abscise at maturity. The effects of removing 50 % of all leaves taken from the lower half of the plant at 40 (pre-flowering) or 60 (post-flowering) days after sowing (DAS) were studied on photosynthesis and growth at 80 DAS and on yield at harvest. A comparison of stomatal and mesophyll effects on photosynthesis upon removal of such leaves was also made. Defoliation at 40 DAS resulted in a higher rate of photosynthesis (P N), growth and yield compared to defoliation at 60 DAS or the no defoliation control. The non-significant variation in stomatal limitation (I S), increased activity of carbonic anhydrase (CA) and constant Ci/Ca ratio in defoliated plants suggest that the main effect on P N was through enhanced mesophyll rather than stomatal effects. Defoliation at 40 DAS caused the greatest emergence of new leaves with rapid growth, which contributed to maximum leaf area as well as leaf and plant dry masses. The favourable effects of defoliation at 40 DAS on photosynthesis and growth were reflected by seed yield and attributing parameters.
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Claims 9
Claim · model-written summary
Defoliation at 40 DAS gave a higher photosynthesis rate than defoliation at 60 DAS or no defoliation.
Verbatim
e0“Defoliation at 40 DAS resulted in a higher rate of photosynthesis (P N), growth and yield compared to defoliation at 60 DAS or the no defoliation control”
t0“mustard”
Claim · model-written summary
Defoliation at 40 DAS gave higher growth than defoliation at 60 DAS or no defoliation.
Verbatim
e0“Defoliation at 40 DAS resulted in a higher rate of photosynthesis (P N), growth and yield compared to defoliation at 60 DAS or the no defoliation control”
t0“mustard”
Claim · model-written summary
Defoliation at 40 DAS gave higher yield than defoliation at 60 DAS or no defoliation.
Verbatim
e0“Defoliation at 40 DAS resulted in a higher rate of photosynthesis (P N), growth and yield compared to defoliation at 60 DAS or the no defoliation control”
t0“mustard”
Claim · model-written summary
Stomatal limitation showed non-significant variation in defoliated mustard plants.
- Taxon
- mustardt0
- Treatment
- defoliated plantse0
- Outcome
- stomatal limitation (I S)e0
- Direction
- non-significant variatione0
Not reportedComparator
Verbatim
e0“The non-significant variation in stomatal limitation (I S), increased activity of carbonic anhydrase (CA) and constant Ci/Ca ratio in defoliated plants suggest that the main effect on P N was through enhanced mesophyll rather than stomatal effects”
t0“mustard”
Claim · model-written summary
Carbonic anhydrase activity increased in defoliated mustard plants.
- Taxon
- mustardt0
- Treatment
- defoliated plantse0
- Gene
- carbonic anhydrase (CA)e0
- Outcome
- activity of carbonic anhydrase (CA)e0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“The non-significant variation in stomatal limitation (I S), increased activity of carbonic anhydrase (CA) and constant Ci/Ca ratio in defoliated plants suggest that the main effect on P N was through enhanced mesophyll rather than stomatal effects”
t0“mustard”
Claim · model-written summary
The Ci/Ca ratio stayed constant in defoliated mustard plants.
Not reportedComparator
Verbatim
e0“The non-significant variation in stomatal limitation (I S), increased activity of carbonic anhydrase (CA) and constant Ci/Ca ratio in defoliated plants suggest that the main effect on P N was through enhanced mesophyll rather than stomatal effects”
t0“mustard”
Claim · model-written summary
The authors infer that the defoliation effect on photosynthesis acted mainly through enhanced mesophyll activity rather than stomatal effects.
Verbatim
e0“The non-significant variation in stomatal limitation (I S), increased activity of carbonic anhydrase (CA) and constant Ci/Ca ratio in defoliated plants suggest that the main effect on P N was through enhanced mesophyll rather than stomatal effects”
t0“mustard”
Claim · model-written summary
Defoliation at 40 DAS caused the greatest emergence of new leaves.
Not reportedComparator
Verbatim
e0“Defoliation at 40 DAS caused the greatest emergence of new leaves with rapid growth”
t0“mustard”
Claim · model-written summary
Defoliation at 40 DAS led to maximum leaf area and leaf and plant dry masses.
- Taxon
- mustardt0
- Treatment
- Defoliation at 40 DASe0
- Outcome
- maximum leaf area as well as leaf and plant dry massese0
- Direction
- maximume0
Not reportedComparator
Verbatim
e0“Defoliation at 40 DAS caused the greatest emergence of new leaves with rapid growth, which contributed to maximum leaf area as well as leaf and plant dry masses”
t0“mustard”