Abstract
Heat and drought are two major limiting factors for perennial pasture production in south eastern Australia. Although previous studies have focused on the effects of prolonged heat and drought stresses on pasture growth and physiology, the effects of short term recurring combined heat and drought stresses and the recovery from them have not been studied in detail. A controlled environment experiment was conducted to investigate the growth and physiological responses of perennial ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.) and chicory (Cichorium intybus L.) plants exposed to two consecutive seven day heat (control = 25/15 °C day/night; moderate = 30/20 °C day/night and severe = 35/30 °C day/night) and/or drought stresses each followed by a seven day recovery period. During the first moderate and severe heat and drought treatments, maximum photochemical efficiency of photosystem II (Fv/Fm), cell membrane permeability and relative leaf water content decreased in chicory and tall fescue compared to perennial ryegrass and cocksfoot. However, during the second moderate heat and drought treatment, all species showed less reduction in the same parameters suggesting that these species acclimated to consecutive moderate heat and drought stresses. Chicory was the only species that was not affected by the second severe heat and drought stress while physiological parameters of all grass species were reduced closer to minimum values. Irrigation mitigated the negative effects of heat stress by cooling the canopies 1–3 °C below air temperatures with the most cooling observed in chicory. All the species exposed to moderate heat and drought were fully recovered and those exposed to severe heat and drought recovered partially at the end of the experiment. These findings suggest that chicory may be a potential species for areas subject to frequent heat and drought stress.
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Claims 8
Claim · model-written summary
First heat and drought treatments reduced three physiological measures in chicory and tall fescue relative to ryegrass and cocksfoot.
- Taxon
- chicory
Cichorium intybuse0 - Treatment
- first moderate and severe heat and drought treatmentse0
- Outcome
- maximum photochemical efficiency of photosystem II (Fv/Fm), cell membrane permeability and relative leaf water contente0
- Direction
- decreasede0
- Comparator
- perennial ryegrass and cocksfoote0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“During the first moderate and severe heat and drought treatments, maximum photochemical efficiency of photosystem II (Fv/Fm), cell membrane permeability and relative leaf water content decreased in chicory and tall fescue compared to perennial ryegrass and cocksfoot.”
Claim · model-written summary
All species showed less reduction in those physiological parameters during the second moderate treatment.
Verbatim
e0“during the second moderate heat and drought treatment, all species showed less reduction in the same parameters”
Claim · model-written summary
Chicory was unaffected by the second severe heat and drought stress.
- Taxon
- ChicoryCichorium intybuse0
- Treatment
- second severe heat and drought stresse0
- Outcome
- not affectede0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chicory was the only species that was not affected by the second severe heat and drought stress”
Claim · model-written summary
Physiological parameters of the grass species fell near minimum values during the second severe treatment.
Not reportedTreatmentComparator
Verbatim
e0“physiological parameters of all grass species were reduced closer to minimum values”
Claim · model-written summary
Irrigation cooled canopies 1–3 °C below air temperature and mitigated heat stress.
- Taxon
- chicoryCichorium intybuse0
- Treatment
- Irrigatione0
- Outcome
- canopiese0
- Direction
- coolinge0
- Value
- 1–3 °Ce0
- Comparator
- air temperaturese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Irrigation mitigated the negative effects of heat stress by cooling the canopies 1–3 °C below air temperatures with the most cooling observed in chicory.”
Claim · model-written summary
Species exposed to moderate heat and drought fully recovered.
Not reportedDirection
Verbatim
e0“All the species exposed to moderate heat and drought were fully recovered”
Claim · model-written summary
Species exposed to severe heat and drought partially recovered.
Not reportedDirection
Verbatim
e0“those exposed to severe heat and drought recovered partially at the end of the experiment”
Claim · model-written summary
The authors suggest chicory for areas with frequent heat and drought.
- Taxon
- chicoryCichorium intybuse0
- Outcome
- potential species for areas subject to frequent heat and drought stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“chicory may be a potential species for areas subject to frequent heat and drought stress”
The same questions in other papers
drought · physiology: photosynthesis · Cichorium intybus (chicory)Results agree
3 papers in the same direction as this paper
- negative
- negative
- negative
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.