Abstract
Growth of temperate lettuce (Lactuca sativa) plants aeroponically in tropical greenhouses under ambient root-zone temperatures (A-RZTs) exposes roots to temperatures of up to 40 degrees C during the middle of the day, and severely limits root and shoot growth. The role of ethylene in inhibiting growth was investigated with just-germinated (24-h-old) seedlings in vitro, and 10-d-old plants grown aeroponically. Compared with seedlings maintained at 20 degrees C, root elongation in vitro was inhibited by 39% and root diameter increased by 25% under a temperature regime (38 degrees C/24 degrees C for 7 h/17 h) that simulated A-RZT in the greenhouse. The effects on root elongation were partially alleviated by supplying the ethylene biosynthesis inhibitors aminooxyacetic acid (100-500 microM) or aminoisobutyric acid (5-100 microM) to the seedlings. Application of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid to seedlings grown at 20 degrees C mimicked the high temperature effects on root elongation (1 microM) and root diameter (1 mM). Compared with plants grown at a constant 20 degrees C root-zone temperature, A-RZT plants showed decreased stomatal conductance, leaf relative water content, photosynthetic CO(2) assimilation, shoot and root biomass, total root length, the number of root tips, and root surface area, but increased average root diameter. Addition of 10 microM ACC to the nutrient solution of plants grown at a constant 20 degrees C root-zone temperature mimicked the effects of A-RZT on these parameters but did not influence relative water content. Addition of 30 microM aminoisobutyric acid or 100 microM aminooxyacetic acid to the nutrient solution of A-RZT plants increased stomatal conductance and relative water content and decreased average root diameter, but had no effect on other root parameters or root and shoot biomass or photosynthetic CO(2) assimilation. Although ethylene is important in regulating root morphology and elongation at A-RZT, the failure of ethylene biosynthesis inhibitors to influence shoot carbon gain limits their use in ameliorating the growth inhibition induced by A-RZT.
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Claims 19
Claim · model-written summary
High temperature inhibited seedling root elongation by 39%.
- Taxon
- Lactuca sativa
Lactuca sativat0 - Treatment
- 38 degrees C/24 degrees C for 7 h/17 he0
- Outcome
- root elongatione0
- Direction
- inhibitede0
- Value
- 39%e0
- Comparator
- 20 degrees Ce0
- Setting
- in vitroe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with seedlings maintained at 20 degrees C, root elongation in vitro was inhibited by 39% and root diameter increased by 25% under a temperature regime (38 degrees C/24 degrees C for 7 h/17 h) that simulated A-RZT in the greenhouse.”
t0“lettuce (Lactuca sativa)”
Claim · model-written summary
High temperature increased root diameter by 25%.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- 38 degrees C/24 degrees C for 7 h/17 he0
- Outcome
- root diametere0
- Direction
- increasede0
- Value
- 25%e0
- Comparator
- 20 degrees Ce0
- Setting
- in vitroe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with seedlings maintained at 20 degrees C, root elongation in vitro was inhibited by 39% and root diameter increased by 25% under a temperature regime (38 degrees C/24 degrees C for 7 h/17 h) that simulated A-RZT in the greenhouse.”
t0“Lactuca sativa”
Claim · model-written summary
Aminooxyacetic acid partially alleviated root elongation inhibition.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- aminooxyacetic acid (100-500 microM)e0
- Outcome
- root elongatione0
- Direction
- partially alleviatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effects on root elongation were partially alleviated by supplying the ethylene biosynthesis inhibitors aminooxyacetic acid (100-500 microM) or aminoisobutyric acid (5-100 microM) to the seedlings.”
t0“Lactuca sativa”
Claim · model-written summary
Aminoisobutyric acid partially alleviated root elongation inhibition.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- aminoisobutyric acid (5-100 microM)e0
- Outcome
- root elongatione0
- Direction
- partially alleviatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effects on root elongation were partially alleviated by supplying the ethylene biosynthesis inhibitors aminooxyacetic acid (100-500 microM) or aminoisobutyric acid (5-100 microM) to the seedlings.”
t0“Lactuca sativa”
Claim · model-written summary
ACC at 1 microM mimicked high-temperature inhibition of root elongation.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- 1-aminocyclopropane-1-carboxylic acide0
- Outcome
- root elongatione0
- Direction
- decreaseinferrede0
- Value
- 1 microMe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Application of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid to seedlings grown at 20 degrees C mimicked the high temperature effects on root elongation (1 microM) and root diameter (1 mM).”
t0“Lactuca sativa”
Claim · model-written summary
ACC at 1 mM mimicked high-temperature increases in root diameter.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- 1-aminocyclopropane-1-carboxylic acide0
- Outcome
- root diametere0
- Direction
- increaseinferrede0
- Value
- 1 mMe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Application of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid to seedlings grown at 20 degrees C mimicked the high temperature effects on root elongation (1 microM) and root diameter (1 mM).”
t0“Lactuca sativa”
Claim · model-written summary
Ambient root temperatures decreased stomatal conductance, water content and carbon assimilation.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- A-RZTe0
- Outcome
- stomatal conductance, leaf relative water content, photosynthetic CO(2) assimilatione0
- Direction
- decreasede0
- Comparator
- constant 20 degrees C root-zone temperaturee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with plants grown at a constant 20 degrees C root-zone temperature, A-RZT plants showed decreased stomatal conductance, leaf relative water content, photosynthetic CO(2) assimilation”
t0“Lactuca sativa”
Claim · model-written summary
Ambient root temperatures decreased shoot and root biomass and total root length.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- A-RZTe0
- Outcome
- shoot and root biomass, total root lengthe0
- Direction
- decreasede0
- Comparator
- constant 20 degrees C root-zone temperaturee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with plants grown at a constant 20 degrees C root-zone temperature, A-RZT plants showed decreased stomatal conductance, leaf relative water content, photosynthetic CO(2) assimilation, shoot and root biomass, total root length, the number of root tips, and root surface area, but increased average root diameter.”
t0“Lactuca sativa”
Claim · model-written summary
Ambient root temperatures decreased root tip number and root surface area.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- A-RZTe0
- Outcome
- the number of root tips, and root surface areae0
- Direction
- decreasede0
- Comparator
- constant 20 degrees C root-zone temperaturee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with plants grown at a constant 20 degrees C root-zone temperature, A-RZT plants showed decreased stomatal conductance, leaf relative water content, photosynthetic CO(2) assimilation, shoot and root biomass, total root length, the number of root tips, and root surface area, but increased average root diameter.”
t0“Lactuca sativa”
Claim · model-written summary
Ambient root temperatures increased average root diameter.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- A-RZTe0
- Outcome
- average root diametere0
- Direction
- increasede0
- Comparator
- constant 20 degrees C root-zone temperaturee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with plants grown at a constant 20 degrees C root-zone temperature, A-RZT plants showed decreased stomatal conductance, leaf relative water content, photosynthetic CO(2) assimilation, shoot and root biomass, total root length, the number of root tips, and root surface area, but increased average root diameter.”
t0“Lactuca sativa”
Claim · model-written summary
ACC decreased conductance and assimilation, mimicking ambient-temperature responses.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- 10 microM ACCe0
- Outcome
- stomatal conductancee1
- Direction
- decreasede1
- Qualifier
- photosynthetic CO(2) assimilatione1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of 10 microM ACC to the nutrient solution of plants grown at a constant 20 degrees C root-zone temperature mimicked the effects of A-RZT on these parameters but did not influence relative water content.”
e1“decreased stomatal conductance, leaf relative water content, photosynthetic CO(2) assimilation”
t0“Lactuca sativa”
Claim · model-written summary
ACC decreased shoot and root biomass and total root length.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- 10 microM ACCe0
- Outcome
- shoot and root biomass, total root lengthe1
- Direction
- decreaseinferrede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of 10 microM ACC to the nutrient solution of plants grown at a constant 20 degrees C root-zone temperature mimicked the effects of A-RZT on these parameters but did not influence relative water content.”
e1“shoot and root biomass, total root length”
t0“Lactuca sativa”
Claim · model-written summary
ACC decreased root tip number and surface area.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- 10 microM ACCe0
- Outcome
- the number of root tips, and root surface areae1
- Direction
- decreaseinferrede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of 10 microM ACC to the nutrient solution of plants grown at a constant 20 degrees C root-zone temperature mimicked the effects of A-RZT on these parameters but did not influence relative water content.”
e1“the number of root tips, and root surface area”
t0“Lactuca sativa”
Claim · model-written summary
ACC increased average root diameter.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- 10 microM ACCe0
- Outcome
- average root diametere1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of 10 microM ACC to the nutrient solution of plants grown at a constant 20 degrees C root-zone temperature mimicked the effects of A-RZT on these parameters but did not influence relative water content.”
e1“increased average root diameter”
t0“Lactuca sativa”
Claim · model-written summary
ACC did not influence relative water content.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- 10 microM ACCe0
- Outcome
- relative water contente0
- Direction
- did not influencee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of 10 microM ACC to the nutrient solution of plants grown at a constant 20 degrees C root-zone temperature mimicked the effects of A-RZT on these parameters but did not influence relative water content.”
t0“Lactuca sativa”
Claim · model-written summary
Aminoisobutyric acid increased conductance and water content and decreased diameter, while other growth and assimilation measures were unaffected.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- 30 microM aminoisobutyric acide0
- Outcome
- stomatal conductance and relative water contente0
- Direction
- increasede0
- Qualifier
- decreased average root diameter, but had no effect on other root parameters or root and shoot biomass or photosynthetic CO(2) assimilatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of 30 microM aminoisobutyric acid or 100 microM aminooxyacetic acid to the nutrient solution of A-RZT plants increased stomatal conductance and relative water content and decreased average root diameter, but had no effect on other root parameters or root and shoot biomass or photosynthetic CO(2) assimilation.”
t0“Lactuca sativa”
Claim · model-written summary
Aminooxyacetic acid increased conductance and water content and decreased diameter, while other growth and assimilation measures were unaffected.
- Taxon
- Lactuca sativaLactuca sativat0
- Treatment
- 100 microM aminooxyacetic acide0
- Outcome
- stomatal conductance and relative water contente0
- Direction
- increasede0
- Qualifier
- decreased average root diameter, but had no effect on other root parameters or root and shoot biomass or photosynthetic CO(2) assimilatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of 30 microM aminoisobutyric acid or 100 microM aminooxyacetic acid to the nutrient solution of A-RZT plants increased stomatal conductance and relative water content and decreased average root diameter, but had no effect on other root parameters or root and shoot biomass or photosynthetic CO(2) assimilation.”
t0“Lactuca sativa”
Claim · model-written summary
Ethylene regulates root morphology and elongation at ambient root temperatures.
- Taxon
- Lactuca sativaLactuca sativat0
- Compound
- ethylenee0
- Outcome
- root morphology and elongatione0
- Qualifier
- A-RZTe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Although ethylene is important in regulating root morphology and elongation at A-RZT”
t0“Lactuca sativa”
Claim · model-written summary
Biosynthesis inhibitors have limited use for ameliorating ambient-temperature growth inhibition because shoot carbon gain did not improve.
- Taxon
- Lactuca sativaLactuca sativat0
- Outcome
- limits their use in ameliorating the growth inhibition induced by A-RZTe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the failure of ethylene biosynthesis inhibitors to influence shoot carbon gain limits their use in ameliorating the growth inhibition induced by A-RZT.”
t0“Lactuca sativa”
The same questions in other papers
1-aminocyclopropanecarboxylic acid · growth · Lactuca sativa (garden lettuce)Results differ
2 papers in the same direction as this paper · 7 in the opposite direction
- positive
- positive
- positive
6 papers more in this group
See all 10 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.