Abstract
A field experiment with 15 genotypes of rice (Oryza saliva L.) was carried out during the rainy season of 1999 and 2000 to understand the photosynthetic basis of yield under low temperature in hills. Exposure of rice genotypes to low temperature conditions during reproductive phase was made by altering the dates of sowing, ie normal and 1 month late. The rate of photosynthesis (r = 0.584*) and canopy photosynthesis (r = 0.830**) estimated during grain-filling phase showed significant positive correlation with grain yield under normal planting and poor association under low temperature condition, ie late planting. Rates of canopy photosynthesis during the early phase of plant development under both plantings were found almost similar, ie no reduction in nursery bed and 2.71% at vegetative stage. A significant reduction in rates of photosynthesis (36.68%), canopy photosynthesis (44.14%), transpiration (29.30%), stomatal conductance (76.80%) and level of photosynthetic pigments (52.51%), nitrate reductase (NR) activity (51.61%) was observed at grain-filling stage under low temperature condition. Besides, a reduction in the grain-filling rate was also noted under late planting due to low temperature.Harvest index (HI) showed the significant positive association with grain yield (r = 0.772**) under low temperature condition only, which in turn indicated that the low temperature reduced the partitioning of photo-assimilates which resulted in poor yield. A significant relationship of grain sterility (r = - 0.836**), harvest index (r = 0.929**), panicle weight (r = 0.574*), NR activity (r = 567*), anthocyanins content (r = 0.561*) with cold-tolerance efficiency was observed.
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Claims 19
Claim · model-written summary
Photosynthesis rate at grain filling correlated significantly and positively with grain yield under normal planting (r = 0.584*).
- Taxon
- rice
Oryza sativat0 - Organ / stage
- grain-filling phasee1
- Treatment
- normal plantinge1
- Outcome
- grain yielde1
- Direction
- positivee1
- Value
- r = 0.584*e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e1“The rate of photosynthesis (r = 0.584*) and canopy photosynthesis (r = 0.830**) estimated during grain-filling phase showed significant positive correlation with grain yield under normal planting”
Claim · model-written summary
Canopy photosynthesis at grain filling correlated significantly and positively with grain yield under normal planting (r = 0.830**).
- Taxon
- riceOryza sativat0
- Organ / stage
- grain-filling phasee1
- Treatment
- normal plantinge1
- Outcome
- grain yielde1
- Direction
- positivee1
- Value
- r = 0.830**e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e1“The rate of photosynthesis (r = 0.584*) and canopy photosynthesis (r = 0.830**) estimated during grain-filling phase showed significant positive correlation with grain yield under normal planting”
Claim · model-written summary
The association of photosynthesis with grain yield was poor under low temperature (late planting).
- Taxon
- riceOryza sativat0
- Treatment
- low temperature conditione2
- Outcome
- grain yielde2
- Direction
- poore2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e2“showed significant positive correlation with grain yield under normal planting and poor association under low temperature condition, ie late planting”
Claim · model-written summary
Canopy photosynthesis in the nursery bed under both plantings showed no reduction.
- Taxon
- riceOryza sativat0
- Organ / stage
- nursery bede3
- Treatment
- both plantingse3
- Outcome
- canopy photosynthesise3
- Direction
- no reductione3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e3“Rates of canopy photosynthesis during the early phase of plant development under both plantings were found almost similar, ie no reduction in nursery bed and 2.71% at vegetative stage”
Claim · model-written summary
Canopy photosynthesis at the vegetative stage was reduced by 2.71% under both plantings.
- Taxon
- riceOryza sativat0
- Organ / stage
- vegetative stagee3
- Treatment
- both plantingse3
- Outcome
- canopy photosynthesise3
- Value
- 2.71%e3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e3“Rates of canopy photosynthesis during the early phase of plant development under both plantings were found almost similar, ie no reduction in nursery bed and 2.71% at vegetative stage”
Claim · model-written summary
Rate of photosynthesis at grain filling was reduced by 36.68% under low temperature.
- Taxon
- riceOryza sativat0
- Organ / stage
- grain-filling stagee4
- Treatment
- low temperature conditione4
- Outcome
- rates of photosynthesise4
- Direction
- reductione4
- Value
- 36.68%e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e4“A significant reduction in rates of photosynthesis (36.68%), canopy photosynthesis (44.14%), transpiration (29.30%), stomatal conductance (76.80%) and level of photosynthetic pigments (52.51%), nitrate reductase (NR) activity (51.61%) was observed at grain-filling stage under low temperature condition”
Claim · model-written summary
Canopy photosynthesis at grain filling was reduced by 44.14% under low temperature.
- Taxon
- riceOryza sativat0
- Organ / stage
- grain-filling stagee4
- Treatment
- low temperature conditione4
- Outcome
- canopy photosynthesise4
- Direction
- reductione4
- Value
- 44.14%e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e4“A significant reduction in rates of photosynthesis (36.68%), canopy photosynthesis (44.14%), transpiration (29.30%), stomatal conductance (76.80%) and level of photosynthetic pigments (52.51%), nitrate reductase (NR) activity (51.61%) was observed at grain-filling stage under low temperature condition”
Claim · model-written summary
Transpiration at grain filling was reduced by 29.30% under low temperature.
- Taxon
- riceOryza sativat0
- Organ / stage
- grain-filling stagee4
- Treatment
- low temperature conditione4
- Outcome
- transpiratione4
- Direction
- reductione4
- Value
- 29.30%e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e4“A significant reduction in rates of photosynthesis (36.68%), canopy photosynthesis (44.14%), transpiration (29.30%), stomatal conductance (76.80%) and level of photosynthetic pigments (52.51%), nitrate reductase (NR) activity (51.61%) was observed at grain-filling stage under low temperature condition”
Claim · model-written summary
Stomatal conductance at grain filling was reduced by 76.80% under low temperature.
- Taxon
- riceOryza sativat0
- Organ / stage
- grain-filling stagee4
- Treatment
- low temperature conditione4
- Outcome
- stomatal conductancee4
- Direction
- reductione4
- Value
- 76.80%e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e4“A significant reduction in rates of photosynthesis (36.68%), canopy photosynthesis (44.14%), transpiration (29.30%), stomatal conductance (76.80%) and level of photosynthetic pigments (52.51%), nitrate reductase (NR) activity (51.61%) was observed at grain-filling stage under low temperature condition”
Claim · model-written summary
Level of photosynthetic pigments at grain filling was reduced by 52.51% under low temperature.
- Taxon
- riceOryza sativat0
- Organ / stage
- grain-filling stagee4
- Treatment
- low temperature conditione4
- Outcome
- level of photosynthetic pigmentse4
- Direction
- reductione4
- Value
- 52.51%e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e4“A significant reduction in rates of photosynthesis (36.68%), canopy photosynthesis (44.14%), transpiration (29.30%), stomatal conductance (76.80%) and level of photosynthetic pigments (52.51%), nitrate reductase (NR) activity (51.61%) was observed at grain-filling stage under low temperature condition”
Claim · model-written summary
Nitrate reductase activity at grain filling was reduced by 51.61% under low temperature.
- Taxon
- riceOryza sativat0
- Organ / stage
- grain-filling stagee4
- Treatment
- low temperature conditione4
- Outcome
- nitrate reductase (NR) activitye4
- Direction
- reductione4
- Value
- 51.61%e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e4“A significant reduction in rates of photosynthesis (36.68%), canopy photosynthesis (44.14%), transpiration (29.30%), stomatal conductance (76.80%) and level of photosynthetic pigments (52.51%), nitrate reductase (NR) activity (51.61%) was observed at grain-filling stage under low temperature condition”
Claim · model-written summary
Grain-filling rate was reduced under late planting due to low temperature.
- Taxon
- riceOryza sativat0
- Treatment
- late plantinge5
- Outcome
- grain-filling ratee5
- Direction
- reductione5
- Qualifier
- due to low temperaturee5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e5“a reduction in the grain-filling rate was also noted under late planting due to low temperature”
Claim · model-written summary
Harvest index was significantly and positively associated with grain yield under low temperature (r = 0.772**).
- Taxon
- riceOryza sativat0
- Treatment
- low temperature conditione6
- Outcome
- grain yielde6
- Direction
- positivee6
- Value
- r = 0.772**e6
- Qualifier
- Harvest index (HI)e6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e6“Harvest index (HI) showed the significant positive association with grain yield (r = 0.772**) under low temperature condition only”
Claim · model-written summary
The authors interpret that low temperature reduced the partitioning of photo-assimilates, which resulted in poor yield.
- Taxon
- riceOryza sativat0
- Outcome
- poor yielde7
- Qualifier
- reduced the partitioning of photo-assimilatese7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e7“the low temperature reduced the partitioning of photo-assimilates which resulted in poor yield”
Claim · model-written summary
Grain sterility was significantly related to cold-tolerance efficiency (r = - 0.836**), negatively.
- Taxon
- riceOryza sativat0
- Outcome
- grain sterilitye0
- Direction
- decreaseinferrede0
- Value
- r = - 0.836**e0
- Comparator
- cold-tolerance efficiencye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e0“A significant relationship of grain sterility (r = - 0.836**), harvest index (r = 0.929**), panicle weight (r = 0.574*), NR activity (r = 567*), anthocyanins content (r = 0.561*) with cold-tolerance efficiency was observed”
Claim · model-written summary
Harvest index was significantly related to cold-tolerance efficiency (r = 0.929**), positively.
- Taxon
- riceOryza sativat0
- Outcome
- harvest indexe0
- Direction
- increaseinferrede0
- Value
- r = 0.929**e0
- Comparator
- cold-tolerance efficiencye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e0“A significant relationship of grain sterility (r = - 0.836**), harvest index (r = 0.929**), panicle weight (r = 0.574*), NR activity (r = 567*), anthocyanins content (r = 0.561*) with cold-tolerance efficiency was observed”
Claim · model-written summary
Panicle weight was significantly related to cold-tolerance efficiency (r = 0.574*), positively.
- Taxon
- riceOryza sativat0
- Outcome
- panicle weighte0
- Direction
- increaseinferrede0
- Value
- r = 0.574*e0
- Comparator
- cold-tolerance efficiencye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e0“A significant relationship of grain sterility (r = - 0.836**), harvest index (r = 0.929**), panicle weight (r = 0.574*), NR activity (r = 567*), anthocyanins content (r = 0.561*) with cold-tolerance efficiency was observed”
Claim · model-written summary
NR activity was significantly related to cold-tolerance efficiency (r = 567*); the sign is not stated.
- Taxon
- riceOryza sativat0
- Outcome
- NR activitye0
- Value
- r = 567*e0
- Comparator
- cold-tolerance efficiencye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e0“A significant relationship of grain sterility (r = - 0.836**), harvest index (r = 0.929**), panicle weight (r = 0.574*), NR activity (r = 567*), anthocyanins content (r = 0.561*) with cold-tolerance efficiency was observed”
Claim · model-written summary
Anthocyanins content was significantly related to cold-tolerance efficiency (r = 0.561*), positively.
- Taxon
- riceOryza sativat0
- Outcome
- anthocyanins contente0
- Direction
- increaseinferrede0
- Value
- r = 0.561*e0
- Comparator
- cold-tolerance efficiencye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“performance of rice (Oryza sativa) genotypes”
e0“A significant relationship of grain sterility (r = - 0.836**), harvest index (r = 0.929**), panicle weight (r = 0.574*), NR activity (r = 567*), anthocyanins content (r = 0.561*) with cold-tolerance efficiency was observed”
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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.