Abstract
Spring wheat plants were grown in a cage with a glass roof until three days after anthesis and then subjected to treatments in constant environment rooms with any one of all combinations of four irradiances and two concentrations of carbon dioxide. The photoperiod was 16 h and day/night temperatures 19°C/14°C. Growth and yield of grain were saturated at the two brightest irradiances. Carbon dioxide enrichment from 350 to 1200 mm3 dm−3 increased shoot dry weight and grain yield at final harvest at all irradiances, by averages of 10.5 (not significant) and 23.5 (significant) percent respectively. However, increasing the irradiance from 150 to 613 μE m−2 s−1 caused much larger yield increases (approximately 3-fold). Increased grain production by increased light was caused by both increases in dry weight per grain and by increases in grain number per spikelet. The increase caused by CO2 enrichment was mainly because of increased dry weight per grain. Increase in ear dry weight caused by CO2 enrichment took place between 30 and 60 d after anthesis. The increase in shoot dry weight took place immediately after exposure to increased CO2 from 3 to 15 d after anthesis. Net photosynthesis by flag leaves on the main shoots was almost doubled 16 d after anthesis by the CO2 enrichment even though stomatal resistance was also doubled. However, this increase was not reflected by a proportional increase in yield, probably because increased mutual shading by bigger stems and late tillers reduced total assimilation and because of increased respiration by the shoots. The increase in photosynthesis was not due to a decrease in photorespiration but to an increase in gross photosynthesis.
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Claims 14
Claim · model-written summary
Growth and grain yield saturated at the two brightest irradiances.
- Taxon
- wheat
Triticum aestivumt0 - Outcome
- Growth and yield of graine0
- Direction
- saturatede0
- Qualifier
- two brightest irradiancese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Growth and yield of grain were saturated at the two brightest irradiances.”
t0“Wheat”
Claim · model-written summary
CO2 enrichment increased shoot dry weight by 10.5 percent without statistical significance.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- Carbon dioxide enrichment from 350 to 1200 mm3 dm−3e0
- Outcome
- shoot dry weighte0
- Direction
- increasede0
- Value
- 10.5e0
- Qualifier
- at final harvest at all irradiancese0
- Comparator
- 350e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Carbon dioxide enrichment from 350 to 1200 mm3 dm−3 increased shoot dry weight and grain yield at final harvest at all irradiances, by averages of 10.5 (not significant) and 23.5 (significant) percent respectively.”
t0“Wheat”
Claim · model-written summary
CO2 enrichment increased grain yield by 23.5 percent significantly.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- Carbon dioxide enrichment from 350 to 1200 mm3 dm−3e0
- Outcome
- grain yielde0
- Direction
- increasede0
- Value
- 23.5e0
- Qualifier
- at final harvest at all irradiancese0
- Comparator
- 350e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Carbon dioxide enrichment from 350 to 1200 mm3 dm−3 increased shoot dry weight and grain yield at final harvest at all irradiances, by averages of 10.5 (not significant) and 23.5 (significant) percent respectively.”
t0“Wheat”
Claim · model-written summary
Increasing irradiance produced approximately threefold yield increases.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- increasing the irradiance from 150 to 613 μE m−2 s−1e0
- Outcome
- yielde0
- Direction
- increasese0
- Value
- approximately 3-folde0
- Comparator
- 150e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increasing the irradiance from 150 to 613 μE m−2 s−1 caused much larger yield increases (approximately 3-fold)”
t0“Wheat”
Claim · model-written summary
Increased light raised dry weight per grain.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- increased lighte0
- Outcome
- dry weight per graine0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased grain production by increased light was caused by both increases in dry weight per grain and by increases in grain number per spikelet.”
t0“Wheat”
Claim · model-written summary
Increased light raised grain number per spikelet.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- increased lighte0
- Outcome
- grain number per spikelete0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased grain production by increased light was caused by both increases in dry weight per grain and by increases in grain number per spikelet.”
t0“Wheat”
Claim · model-written summary
CO2 enrichment raised dry weight per grain.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- CO2 enrichmente0
- Outcome
- dry weight per graine0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The increase caused by CO2 enrichment was mainly because of increased dry weight per grain.”
t0“Wheat”
Claim · model-written summary
CO2 enrichment increased ear dry weight between 30 and 60 days after anthesis.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- CO2 enrichmente0
- Outcome
- ear dry weighte0
- Direction
- Increasee0
- Qualifier
- between 30 and 60 d after anthesise0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increase in ear dry weight caused by CO2 enrichment took place between 30 and 60 d after anthesis.”
t0“Wheat”
Claim · model-written summary
CO2 enrichment increased shoot dry weight immediately after exposure.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- increased CO2e0
- Outcome
- shoot dry weighte0
- Direction
- increasee0
- Qualifier
- from 3 to 15 d after anthesise0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The increase in shoot dry weight took place immediately after exposure to increased CO2 from 3 to 15 d after anthesis.”
t0“Wheat”
Claim · model-written summary
CO2 enrichment almost doubled flag leaf net photosynthesis at day 16.
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- flag leavese0
- Treatment
- CO2 enrichmente0
- Outcome
- Net photosynthesise0
- Direction
- almost doublede0
- Value
- almost doublede0
- Qualifier
- 16 d after anthesise0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Net photosynthesis by flag leaves on the main shoots was almost doubled 16 d after anthesis by the CO2 enrichment”
t0“Wheat”
Claim · model-written summary
CO2 enrichment also doubled stomatal resistance.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- CO2 enrichmente1
- Outcome
- stomatal resistancee0
- Direction
- doublede0
- Value
- doublede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“even though stomatal resistance was also doubled”
t0“Wheat”
e1“The increase caused by CO2 enrichment was mainly because of increased dry weight per grain.”
Claim · model-written summary
Greater photosynthesis did not yield a proportional yield increase.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- CO2 enrichmente1
- Outcome
- yielde0
- Direction
- not reflected by a proportional increasee0
- Qualifier
- this increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this increase was not reflected by a proportional increase in yield”
t0“Wheat”
e1“The increase caused by CO2 enrichment was mainly because of increased dry weight per grain.”
Claim · model-written summary
Increased mutual shading and shoot respiration probably limited assimilation and yield response.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- total assimilatione0
- Direction
- reducede0
- Qualifier
- increased mutual shading by bigger stems and late tillerse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“probably because increased mutual shading by bigger stems and late tillers reduced total assimilation and because of increased respiration by the shoots”
t0“Wheat”
Claim · model-written summary
The photosynthesis increase arose from higher gross photosynthesis rather than lower photorespiration.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- photosynthesise0
- Qualifier
- an increase in gross photosynthesise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The increase in photosynthesis was not due to a decrease in photorespiration but to an increase in gross photosynthesis.”
t0“Wheat”
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