Abstract
The effects of moderate low temperature(15℃/10℃, day/night) and severe low temperature(10℃/5℃, day/night)on photosynthesis and chlorophyll fluorescence characteristics were studied in watermelon cultivar ‘Zaojia8424'. The results showed that:(1) The chlorophyll(a+b) content, net photosynthetic rate(Pn), transpiration rate(Tr), stomatal conductance(Gs) were gradually decreased under low temperature stress, and the lower the temperature was, the greater the photosynthetic parameters decreased. Severe low temperature stress reduced Pnto 1.56 and decreased by 85.9% compared to non-stress after 6 d of treatment, indicating that severe low temperature caused serious damage to photosynthetic apparatus of watermelon seedlings and greatly inhibited the photosynthesis.(2) Intercellular CO2concentration(Ci) shown to decrease under moderate low temperature stress, consistent with the change trend of Pnand Gs, indicating that stomatal restriction was the main factor leading to reduction of photosynthetic rate. However, severe low temperature stress increased Ci, demonstrating a fact that non-stomatal restriction was the main factor for the decrease of Pn. The chlorophyll a/b increased under low temperature stress, which may be a self-protective mechanism of watermelon seedlings to low temperature with light stress, because the relatively small amount of chlorophyll b could avoid photoinhibition caused by excessive light absorbed by chlorophyll.(3) Low temperature stress led a significant decline in the maximum photochemical efficiency of photosystem Ⅱ(Fv/Fm) and photochemical quenching coefficient(qP), severe low temperature stress also caused a decrease in the non-photochemical quenching coefficient(qN), whereas qN showed a increase under moderate low temperature stress. This suggested that watermelon seedlings grown under moderate low temperature could consume excessive light energy absorbed by antenna pigment through thermal dissipation in xanthophylls cycle to alleviate the damage of PS Ⅱ, whereas under severe low temperature stress, the photo-protective mechanisms of watermelon seedlings destroyed and it also caused a irreversible damage to photosynthetic apparatus.
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Claims 16
Claim · model-written summary
Low temperature gradually decreased chlorophyll content, net photosynthetic rate and transpiration rate, with greater decreases at lower temperatures.
- Taxon
- watermelon
Citrullus lanatust0 - Treatment
- low temperature stresse0
- Outcome
- chlorophyll(a+b) content, net photosynthetic rate(Pn), transpiration rate(Tr)e0
- Direction
- gradually decreasede0
- Qualifier
- the lower the temperature was, the greater the photosynthetic parameters decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The chlorophyll(a+b) content, net photosynthetic rate(Pn), transpiration rate(Tr), stomatal conductance(Gs) were gradually decreased under low temperature stress, and the lower the temperature was, the greater the photosynthetic parameters decreased”
t0“watermelon”
Claim · model-written summary
Low temperature gradually decreased stomatal conductance, with greater decreases at lower temperatures.
- Taxon
- watermelonCitrullus lanatust0
- Treatment
- low temperature stresse0
- Outcome
- stomatal conductance(Gs)e0
- Direction
- gradually decreasede0
- Qualifier
- the lower the temperature was, the greater the photosynthetic parameters decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“stomatal conductance(Gs) were gradually decreased under low temperature stress, and the lower the temperature was, the greater the photosynthetic parameters decreased”
t0“watermelon”
Claim · model-written summary
Severe low temperature reduced Pn to 1.56 after six days.
- Taxon
- watermelonCitrullus lanatust0
- Treatment
- Severe low temperature stresse0
- Outcome
- Pne0
- Direction
- reducede0
- Value
- 1.56e0
- Qualifier
- after 6 d of treatmente0
- Comparator
- non-stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Severe low temperature stress reduced Pnto 1.56 and decreased by 85.9% compared to non-stress after 6 d of treatment”
t0“watermelon”
Claim · model-written summary
Severe low temperature decreased Pn by 85.9% relative to non-stress after six days.
- Taxon
- watermelonCitrullus lanatust0
- Treatment
- Severe low temperature stresse0
- Outcome
- Pne0
- Direction
- decreasede0
- Value
- 85.9%e0
- Qualifier
- after 6 d of treatmente0
- Comparator
- non-stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Severe low temperature stress reduced Pnto 1.56 and decreased by 85.9% compared to non-stress after 6 d of treatment”
t0“watermelon”
Claim · model-written summary
Severe low temperature was interpreted to seriously damage the photosynthetic apparatus and inhibit photosynthesis.
- Taxon
- watermelonCitrullus lanatuse0
- Treatment
- severe low temperaturee0
- Outcome
- photosynthesise0
- Direction
- greatly inhibitede0
- Qualifier
- serious damage to photosynthetic apparatuse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“severe low temperature caused serious damage to photosynthetic apparatus of watermelon seedlings and greatly inhibited the photosynthesis”
Claim · model-written summary
Moderate low temperature decreased intercellular CO2 concentration.
- Taxon
- watermelonCitrullus lanatust0
- Treatment
- moderate low temperature stresse0
- Outcome
- Intercellular CO2concentration(Ci)e0
- Direction
- decreasee0
- Qualifier
- consistent with the change trend of Pnand Gse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Intercellular CO2concentration(Ci) shown to decrease under moderate low temperature stress, consistent with the change trend of Pnand Gs”
t0“watermelon”
Claim · model-written summary
Stomatal restriction was interpreted as the main cause of reduced photosynthetic rate under moderate low temperature.
- Taxon
- watermelonCitrullus lanatust0
- Treatment
- moderate low temperature stresse0
- Outcome
- reduction of photosynthetic ratee0
- Qualifier
- stomatal restrictione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“under moderate low temperature stress, consistent with the change trend of Pnand Gs, indicating that stomatal restriction was the main factor leading to reduction of photosynthetic rate”
t0“watermelon”
Claim · model-written summary
Severe low temperature increased Ci.
- Taxon
- watermelonCitrullus lanatust0
- Treatment
- severe low temperature stresse0
- Outcome
- Cie0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“severe low temperature stress increased Ci”
t0“watermelon”
Claim · model-written summary
Non-stomatal restriction was interpreted as the main cause of decreased Pn under severe low temperature.
- Taxon
- watermelonCitrullus lanatust0
- Treatment
- severe low temperature stresse0
- Outcome
- decrease of Pne0
- Qualifier
- non-stomatal restrictione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“severe low temperature stress increased Ci, demonstrating a fact that non-stomatal restriction was the main factor for the decrease of Pn”
t0“watermelon”
Claim · model-written summary
Low temperature increased chlorophyll a/b.
- Taxon
- watermelonCitrullus lanatust0
- Treatment
- low temperature stresse0
- Outcome
- chlorophyll a/be0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The chlorophyll a/b increased under low temperature stress”
t0“watermelon”
Claim · model-written summary
Increased chlorophyll a/b may protect watermelon against photoinhibition by reducing light absorption by chlorophyll b.
- Taxon
- watermelonCitrullus lanatuse0
- Treatment
- low temperature stresse0
- Outcome
- avoid photoinhibitione0
- Qualifier
- relatively small amount of chlorophyll be0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The chlorophyll a/b increased under low temperature stress, which may be a self-protective mechanism of watermelon seedlings to low temperature with light stress, because the relatively small amount of chlorophyll b could avoid photoinhibition caused by excessive light absorbed by chlorophyll”
Claim · model-written summary
Low temperature significantly reduced Fv/Fm and qP.
- Taxon
- watermelonCitrullus lanatust0
- Treatment
- Low temperature stresse0
- Outcome
- maximum photochemical efficiency of photosystem Ⅱ(Fv/Fm) and photochemical quenching coefficient(qP)e0
- Direction
- declinee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Low temperature stress led a significant decline in the maximum photochemical efficiency of photosystem Ⅱ(Fv/Fm) and photochemical quenching coefficient(qP)”
t0“watermelon”
Claim · model-written summary
Severe low temperature decreased qN.
- Taxon
- watermelonCitrullus lanatust0
- Treatment
- severe low temperature stresse0
- Outcome
- non-photochemical quenching coefficient(qN)e0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“severe low temperature stress also caused a decrease in the non-photochemical quenching coefficient(qN)”
t0“watermelon”
Claim · model-written summary
Moderate low temperature increased qN.
- Taxon
- watermelonCitrullus lanatust0
- Treatment
- moderate low temperature stresse0
- Outcome
- qNe0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“qN showed a increase under moderate low temperature stress”
t0“watermelon”
Claim · model-written summary
Under moderate cold, thermal dissipation through the xanthophyll cycle was interpreted to alleviate photosystem II damage.
- Taxon
- watermelonCitrullus lanatuse0
- Treatment
- moderate low temperaturee0
- Outcome
- alleviate the damage of PS Ⅱe0
- Qualifier
- thermal dissipation in xanthophylls cyclee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“watermelon seedlings grown under moderate low temperature could consume excessive light energy absorbed by antenna pigment through thermal dissipation in xanthophylls cycle to alleviate the damage of PS Ⅱ”
Claim · model-written summary
Severe low temperature was interpreted to destroy photoprotection and irreversibly damage the photosynthetic apparatus.
- Taxon
- watermelonCitrullus lanatuse0
- Treatment
- severe low temperature stresse0
- Outcome
- irreversible damage to photosynthetic apparatuse0
- Qualifier
- photo-protective mechanismse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“under severe low temperature stress, the photo-protective mechanisms of watermelon seedlings destroyed and it also caused a irreversible damage to photosynthetic apparatus”
The same questions in other papers
cold · physiology: gas exchange · Citrullus lanatus (watermelon)Results agree
1 paper in the same direction as this paper
- negative
cold · physiology: photosynthesis · Citrullus lanatus (watermelon)Results agree
4 papers in the same direction as this paper
- negative
- negative
- negative
1 paper more in this group
See all 5 papers →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.