Abstract
Depending on their habitat conditions, plants can greatly change the growth rate of their roots. However, the mechanisms of such responses remain insufficiently clear. The influence of a low level of illumination on the content of endogenous auxins, their localization in leaves and transport from shoots to roots were studied and related to the lateral root branching of barley plants. Following two days’ reduction in illumination, a 10-fold reduction in the emergence of lateral roots was found. Auxin (IAA, indole-3-acetic acid) content decreased by 84% in roots and by 30% in shoots, and immunolocalization revealed lowered IAA levels in phloem cells of leaf sections. The reduced content of IAA found in the plants under low light suggests an inhibition of production of this hormone under these conditions. At the same time, two-fold downregulation of the LAX3 gene expression, facilitating IAA influx into the cells, was detected in the roots, as well as a decline in auxin diffusion from shoots through the phloem by about 60%. It was suggested that the reduced emergence of lateral roots in barley under a low level of illumination was due to a disturbance of auxin transport through the phloem and down-regulation of the genes responsible for auxin transport in plant roots. The results confirm the importance of the long distance transport of auxins for the control of the growth of roots under conditions of low light. Further study of the mechanisms that control the transport of auxins from shoots to roots in other plant species is required.
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Claims 7
Claim · model-written summary
Low illumination reduced lateral root emergence in barley about 10-fold
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaret0 - Treatment
- low level of illuminatione1
- Outcome
- emergence of lateral rootse2
- Direction
- reductione2
- Value
- 10-folde2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
t0“Lateral Roots in Barley Plants”
e1“The influence of a low level of illumination on the content of endogenous auxins”
e2“a 10-fold reduction in the emergence of lateral roots was found”
Claim · model-written summary
Low illumination decreased IAA content by 84% in roots
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- rootse3
- Treatment
- low level of illuminatione1
- Outcome
- Auxin (IAA, indole-3-acetic acid) contente3
- Direction
- decreasede3
- Value
- 84%e3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Lateral Roots in Barley Plants”
e1“The influence of a low level of illumination on the content of endogenous auxins”
e3“Auxin (IAA, indole-3-acetic acid) content decreased by 84% in roots and by 30% in shoots”
Claim · model-written summary
Low illumination decreased IAA content by 30% in shoots
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- shootse3
- Treatment
- low level of illuminatione1
- Outcome
- Auxin (IAA, indole-3-acetic acid) contente3
- Direction
- decreasede3
- Value
- 30%e3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Lateral Roots in Barley Plants”
e1“The influence of a low level of illumination on the content of endogenous auxins”
e3“Auxin (IAA, indole-3-acetic acid) content decreased by 84% in roots and by 30% in shoots”
Claim · model-written summary
Low illumination lowered IAA levels in phloem cells of leaf sections
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- phloem cells of leaf sectionse4
- Treatment
- low level of illuminatione1
- Outcome
- IAA levelse4
- Direction
- lowerede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Lateral Roots in Barley Plants”
e1“The influence of a low level of illumination on the content of endogenous auxins”
e4“immunolocalization revealed lowered IAA levels in phloem cells of leaf sections”
Claim · model-written summary
Low illumination caused two-fold downregulation of LAX3 expression in roots
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- rootse5
- Treatment
- low level of illuminatione1
- Gene
- LAX3e5
- Outcome
- gene expressione5
- Direction
- downregulatione5
- Value
- two-folde5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Lateral Roots in Barley Plants”
e1“The influence of a low level of illumination on the content of endogenous auxins”
e5“two-fold downregulation of the LAX3 gene expression, facilitating IAA influx into the cells, was detected in the roots”
Claim · model-written summary
Low illumination decreased auxin diffusion from shoots through the phloem by about 60%
- Taxon
- barleyHordeum vulgaret0
- Treatment
- low level of illuminatione1
- Outcome
- auxin diffusion from shoots through the phloeme6
- Direction
- declinee6
- Value
- about 60%e6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Lateral Roots in Barley Plants”
e1“The influence of a low level of illumination on the content of endogenous auxins”
e6“a decline in auxin diffusion from shoots through the phloem by about 60%”
Claim · model-written summary
Reduced lateral root emergence under low light is suggested to result from disturbed phloem auxin transport
- Taxon
- barleyHordeum vulgaret0
- Outcome
- emergence of lateral rootse7
- Qualifier
- disturbance of auxin transport through the phloeme7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Lateral Roots in Barley Plants”
e7“It was suggested that the reduced emergence of lateral roots in barley under a low level of illumination was due to a disturbance of auxin transport through the phloem”
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