Abstract
Opuntia plants grow naturally in areas where temperatures are extreme and highly variable in the day during the entire year. These plants survive through different adaptations to respond to adverse environmental conditions. Despite this capability, it is unknown how CAM photosynthetic activity and growth in Opuntia plantlets is affected by constant heat or cold. Therefore, the main objective of this research was to evaluate the short-term effect of high (40°C) and low (4°C) continuous temperatures on the photosynthetic efficiency, the organic acid content (malic acid) and the relative growth rate (RGR) in seven-month-old Opuntia streptacantha plantlets during 5, 10, and 15 days. Chlorophyll fluorescence analysis allowed us to determine that high temperatures negatively impact the photosynthetic efficiency of O. streptacantha plantlets, which exhibited the lowest values of maximum quantum efficiency of the photosystem II (Fv/Fm = 52%, Fv/F0 = 85%), operational quantum yield of PS (ΦPSII = 65%) and relative electron transport rate (rETR = 65%), as well as highest values of basal fluorescence (F0 = 226%) during 15 days of treatment. Similarly, low temperatures decreased Fv/Fm (16%), Fv/F0 (50%), ΦPSII and rETR (16%). High temperatures also decreased nocturnal acidification in approximately 34-50%, whereas low temperatures increased it by 30-36%. Additionally, both continuous temperatures affected drastically diurnal consumption of malic acid, which was related to a significant RGR inhibition, where the specific photosynthetic structure area component was the most affected. Our results allowed determining that, despite the high tolerance to extreme temperatures described for Opuntia plants, young individuals of O. streptacantha suffered photosynthetic impairment that led to the inhibition of their growth. Thus, the main findings reported in this study can help to predict the potential impact of climatic change on the establishment and survival of succulent species of arid and semiarid regions of Mexico.
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Claims 16
Claim · model-written summary
High temperature reduced Fv/Fm to 52% during 15 days of treatment.
- Taxon
- O. streptacantha
Opuntia streptacanthae0 - Treatment
- high (40°C)e3
- Outcome
- Fv/Fme1
- Direction
- loweste1
- Value
- 52%e1
- Qualifier
- during 15 days of treatmente2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“high temperatures negatively impact the photosynthetic efficiency of O. streptacantha plantlets, which exhibited the lowest values of maximum quantum efficiency of the photosystem II (Fv/Fm = 52%, Fv/F0 = 85%)”
e2“during 15 days of treatment”
e3“high (40°C) and low (4°C) continuous temperatures”
Claim · model-written summary
High temperature reduced Fv/F0 to 85%.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Treatment
- high (40°C)e2
- Outcome
- Fv/F0e1
- Direction
- loweste1
- Value
- 85%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“lowest values of maximum quantum efficiency of the photosystem II (Fv/Fm = 52%, Fv/F0 = 85%)”
e2“high (40°C) and low (4°C) continuous temperatures”
Claim · model-written summary
High temperature reduced ΦPSII to 65%.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Treatment
- high temperaturese2
- Outcome
- ΦPSIIe1
- Direction
- negatively impacte2
- Value
- 65%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“operational quantum yield of PS (ΦPSII = 65%)”
e2“high temperatures negatively impact the photosynthetic efficiency”
Claim · model-written summary
High temperature reduced rETR to 65%.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Treatment
- high temperaturese2
- Outcome
- rETRe1
- Direction
- negatively impacte2
- Value
- 65%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“relative electron transport rate (rETR = 65%)”
e2“high temperatures negatively impact the photosynthetic efficiency”
Claim · model-written summary
High temperature increased F0 to 226%.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Treatment
- high temperaturese2
- Outcome
- F0e1
- Direction
- higheste1
- Value
- 226%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“highest values of basal fluorescence (F0 = 226%)”
e2“high temperatures negatively impact the photosynthetic efficiency”
Claim · model-written summary
Low temperature decreased Fv/Fm by 16%.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Treatment
- low temperaturese1
- Outcome
- Fv/Fme1
- Direction
- decreasede1
- Value
- 16%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“low temperatures decreased Fv/Fm (16%), Fv/F0 (50%), ΦPSII and rETR (16%)”
Claim · model-written summary
Low temperature decreased Fv/F0 by 50%.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Treatment
- low temperaturese1
- Outcome
- Fv/F0e1
- Direction
- decreasede1
- Value
- 50%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“low temperatures decreased Fv/Fm (16%), Fv/F0 (50%), ΦPSII and rETR (16%)”
Claim · model-written summary
Low temperature decreased ΦPSII.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Treatment
- low temperaturese1
- Outcome
- ΦPSIIe1
- Direction
- decreasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“low temperatures decreased Fv/Fm (16%), Fv/F0 (50%), ΦPSII and rETR (16%)”
Claim · model-written summary
Low temperature decreased rETR by 16%.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Treatment
- low temperaturese1
- Outcome
- rETRe1
- Direction
- decreasede1
- Value
- 16%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“low temperatures decreased Fv/Fm (16%), Fv/F0 (50%), ΦPSII and rETR (16%)”
Claim · model-written summary
High temperature decreased nocturnal acidification by approximately 34-50%.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Treatment
- High temperaturese1
- Outcome
- nocturnal acidificatione1
- Direction
- decreasede1
- Value
- 34-50%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“High temperatures also decreased nocturnal acidification in approximately 34-50%”
Claim · model-written summary
Low temperature increased nocturnal acidification by 30-36%.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Treatment
- low temperaturese1
- Outcome
- nocturnal acidificatione2
- Direction
- increasede1
- Value
- 30-36%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“low temperatures increased it by 30-36%”
e2“nocturnal acidification”
Claim · model-written summary
Continuous high temperature affected diurnal malic acid consumption.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Treatment
- high (40°C)e2
- Outcome
- diurnal consumption of malic acide1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“both continuous temperatures affected drastically diurnal consumption of malic acid”
e2“high (40°C) and low (4°C) continuous temperatures”
Claim · model-written summary
Continuous low temperature affected diurnal malic acid consumption.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Treatment
- low (4°C)e2
- Outcome
- diurnal consumption of malic acide1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“both continuous temperatures affected drastically diurnal consumption of malic acid”
e2“high (40°C) and low (4°C) continuous temperatures”
Claim · model-written summary
Changes in diurnal malic acid consumption were associated with significant inhibition of relative growth rate.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Compound
- malic acide1
- Outcome
- RGR inhibitione1
- Direction
- inhibitione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“diurnal consumption of malic acid, which was related to a significant RGR inhibition”
Claim · model-written summary
The specific photosynthetic structure area component was most affected.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Outcome
- specific photosynthetic structure area componente1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“O. streptacantha plantlets”
e1“the specific photosynthetic structure area component was the most affected”
Claim · model-written summary
The authors concluded that photosynthetic impairment inhibited growth in young plantlets under extreme temperature.
- Taxon
- O. streptacanthaOpuntia streptacanthae0
- Outcome
- inhibition of their growthe0
- Qualifier
- photosynthetic impairmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“young individuals of O. streptacantha suffered photosynthetic impairment that led to the inhibition of their growth”