Abstract
Experiments with sunflower and fodder cabbage showed that reversion of the leaf disks lower side upwards (towards the radiation source) decreased the photosynthetic rate by as much as 26% both at full (2. 105 erg. cm−2. sec.−1) and half density of irradiation. On placing two disks one on another the photosynthetic rate was decreased in the upper disk in a similar way as it was on reversion even if it were placed in the normal position (upper side upwards). But assimilation in the lower disk was only a fraction (0–40%) of that of the upper disk and in thick leaves was within the limits of the compensation point. The sum of the increase in dry weight in both disks due to photosynthesis exceeds the increment in one normally placed disk only in thin leaves and at high density of radiation. On the basis of the differences found it is advised to discard experimental samples where a quarter of the disks were reversed during exposure. On evaluating samples in which some of the disks were duplicated in error, it is most accurate to deduct the weight of one control disk from the weight obtained. The decrease in photosynthetic rate found in reversed and duplicated disks is evidently due to the simultaneous effect of differences in the supply of CO2 and radiation energy to the assimilating tissue and apparatus and also to differences in the photosynthetic capacity of different leaf tissues.
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Claims 8
Claim · model-written summary
Reversing sunflower leaf disks reduced photosynthetic rate by as much as 26% at full and half irradiation.
- Taxon
- sunflower
Helianthus annuuse0 - Organ / stage
- leaf diskse0
- Treatment
- reversion of the leaf disks lower side upwardse0
- Outcome
- photosynthetic ratee0
- Direction
- decreasede0
- Value
- 26%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Experiments with sunflower and fodder cabbage showed that reversion of the leaf disks lower side upwards (towards the radiation source) decreased the photosynthetic rate by as much as 26% both at full (2. 105 erg. cm−2. sec.−1) and half density of irradiation”
Claim · model-written summary
Reversing fodder cabbage leaf disks reduced photosynthetic rate by as much as 26% at full and half irradiation.
- Taxon
- fodder cabbagee0
- Organ / stage
- leaf diskse0
- Treatment
- reversion of the leaf disks lower side upwardse0
- Outcome
- photosynthetic ratee0
- Direction
- decreasede0
- Value
- 26%e0
Not reportedComparator
Verbatim
e0“Experiments with sunflower and fodder cabbage showed that reversion of the leaf disks lower side upwards (towards the radiation source) decreased the photosynthetic rate by as much as 26% both at full (2. 105 erg. cm−2. sec.−1) and half density of irradiation”
Claim · model-written summary
Stacking two disks reduced photosynthesis in the upper disk similarly to reversal.
- Organ / stage
- upper diske0
- Treatment
- placing two disks one on anothere0
- Outcome
- photosynthetic ratee0
- Direction
- decreasede0
- Comparator
- reversione0
Not reportedTaxon
Verbatim
e0“On placing two disks one on another the photosynthetic rate was decreased in the upper disk in a similar way as it was on reversion even if it were placed in the normal position (upper side upwards)”
Claim · model-written summary
Lower stacked disks assimilated 0–40% as much as upper disks, reaching the compensation point in thick leaves.
- Outcome
- assimilation in the lower diske0
- Direction
- only a fractione0
- Value
- 0–40%e0
- Qualifier
- in thick leavese0
- Comparator
- upper diske0
Not reportedTaxon
Verbatim
e0“assimilation in the lower disk was only a fraction (0–40%) of that of the upper disk and in thick leaves was within the limits of the compensation point”
Claim · model-written summary
Two disks exceeded one normal disk in total photosynthetic dry-weight gain only in thin leaves at high radiation.
- Treatment
- both diskse0
- Outcome
- increase in dry weighte0
- Direction
- exceedse0
- Qualifier
- only in thin leaves and at high density of radiatione0
- Comparator
- one normally placed diske0
Not reportedTaxon
Verbatim
e0“The sum of the increase in dry weight in both disks due to photosynthesis exceeds the increment in one normally placed disk only in thin leaves and at high density of radiation”
Claim · model-written summary
The authors advise discarding samples when a quarter of leaf disks were reversed.
- Outcome
- discard experimental samples where a quarter of the disks were reversed during exposuree0
Not reportedTaxon
Verbatim
e0“it is advised to discard experimental samples where a quarter of the disks were reversed during exposure”
Claim · model-written summary
For samples with accidentally duplicated disks, the authors advise deducting one control disk weight.
- Outcome
- deduct the weight of one control disk from the weight obtainede0
Not reportedTaxon
Verbatim
e0“it is most accurate to deduct the weight of one control disk from the weight obtained”
Claim · model-written summary
Differences in CO2 and radiation supply and tissue photosynthetic capacity were proposed to explain lower rates in reversed and doubled disks.
- Outcome
- decrease in photosynthetic ratee0
- Qualifier
- differences in the supply of CO2 and radiation energye0
Not reportedTaxon
Verbatim
e0“The decrease in photosynthetic rate found in reversed and duplicated disks is evidently due to the simultaneous effect of differences in the supply of CO2 and radiation energy to the assimilating tissue and apparatus and also to differences in the photosynthetic capacity of different leaf tissues”