Abstract
Water deficit is one of the most important environmental stresses that adversely affect crop growth and production; and symbiotic bacteria have an important role in resistance to drought stress. Growth and nodulation of an alfalfa population originating from Ouargla oasis in association with six rhizobial strains (four local strains: E131, E222, O152 and O172, and two introduced strains: Sm1021 and Sm2011) exposed to three levels of water deficit (75%, 50% and 25% of field capacity) were assessed under greenhouse conditions. Phylogenetic analysis of concatenated sequences of glnII and recA showed that tested strains were closely related to reference strain S. meliloti USDA 1002T at similarity level of 97.76 and 98.07%, respectively. Increasing water stress gradually reduced plant growth and nodulation. At irrigation doses D2 and D3, growth was reduced respectively by 30% and 80% of plant height and by 31% and 72% of root length. Likewise, shoot and root dry weights decreased. The negative effect was more pronounced on shoots (39% and 75%) than on roots (no significant difference between control and D2, and between control and D3). Inoculation increased the capability of the plants to counteract the stress compared to the non-inoculated plants. So, the plants inoculated with Sm2011 and O152 strains increased shoot height, root length, shoot and root dry weights and formed the most efficient symbiotic couples compared to the other strains and non-inoculated control in all water stress levels. Inoculation under water stress was found to significantly affect nodule numbers of alfalfa. Under severe stress, a significantly higher nodule number was obtained with the O152 and Sm2011 strains. Under moderate stress, strains Sm2011, Sm1021 had the best nodulation. Our results show that combining alfalfa and rhizobial strains with superior water stress tolerance is an effective strategy to improve alfalfa productivity in drought affected areas. KEYWORDS: Water stress, alfalfa, Sinorhizobium meliloti, resistance, yield.
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Claims 15
Claim · model-written summary
Increasing water stress gradually reduced alfalfa plant growth and nodulation.
- Taxon
- ALFALFA
Medicago sativat0 - Treatment
- Increasing water stresse1
- Outcome
- plant growth and nodulatione1
- Direction
- reducede1
- Setting
- greenhouse conditionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Increasing water stress gradually reduced plant growth and nodulation”
e0“Growth and nodulation of an alfalfa population originating from Ouargla oasis in association with six rhizobial strains (four local strains: E131, E222, O152 and O172, and two introduced strains: Sm1021 and Sm2011) exposed to three levels of water deficit (75%, 50% and 25% of field capacity) were assessed under greenhouse conditions”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
At irrigation doses D2 and D3, alfalfa plant height was reduced by 30% and 80%.
- Taxon
- ALFALFAMedicago sativat0
- Treatment
- irrigation doses D2 and D3e2
- Outcome
- plant heighte2
- Direction
- reducede2
- Value
- 30% and 80%e2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“At irrigation doses D2 and D3, growth was reduced respectively by 30% and 80% of plant height and by 31% and 72% of root length”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
At irrigation doses D2 and D3, alfalfa root length was reduced by 31% and 72%.
- Taxon
- ALFALFAMedicago sativat0
- Treatment
- irrigation doses D2 and D3e2
- Outcome
- root lengthe2
- Direction
- reducede2
- Value
- 31% and 72%e2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“At irrigation doses D2 and D3, growth was reduced respectively by 30% and 80% of plant height and by 31% and 72% of root length”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
Under increasing water stress, shoot and root dry weights of alfalfa decreased.
- Taxon
- ALFALFAMedicago sativat0
- Treatment
- Increasing water stresse1
- Outcome
- shoot and root dry weightse3
- Direction
- decreasede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Likewise, shoot and root dry weights decreased”
e1“Increasing water stress gradually reduced plant growth and nodulation”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
The negative water-stress effect on alfalfa was more pronounced on shoots (39% and 75%) than on roots.
- Taxon
- ALFALFAMedicago sativat0
- Treatment
- Increasing water stresse1
- Outcome
- shootse4
- Direction
- more pronouncede4
- Value
- 39% and 75%e4
- Comparator
- rootse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“The negative effect was more pronounced on shoots (39% and 75%) than on roots”
e1“Increasing water stress gradually reduced plant growth and nodulation”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
Under moderate and severe water deficit (D2, D3), alfalfa roots showed no significant difference from control.
- Taxon
- ALFALFAMedicago sativat0
- Treatment
- irrigation doses D2 and D3e2
- Outcome
- rootse4
- Direction
- no significant differencee5
- Comparator
- controle5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“no significant difference between control and D2, and between control and D3”
e2“At irrigation doses D2 and D3, growth was reduced respectively by 30% and 80% of plant height and by 31% and 72% of root length”
e4“The negative effect was more pronounced on shoots (39% and 75%) than on roots”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
Inoculation increased the capability of alfalfa to counteract water stress compared with non-inoculated plants.
- Taxon
- ALFALFAMedicago sativat0
- Treatment
- Inoculatione6
- Interactor
- SINORHIZOBIUM MELILOTI
Sinorhizobium melilotit0symbiont - Outcome
- capability of the plants to counteract the stresse6
- Direction
- increasede6
- Comparator
- non-inoculated plantse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“Inoculation increased the capability of the plants to counteract the stress compared to the non-inoculated plants”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
Inoculation with Sm2011 and O152 strains increased alfalfa shoot height and root length under all water stress levels.
- Taxon
- ALFALFAMedicago sativat0
- Treatment
- inoculated with Sm2011 and O152 strainse7
- Interactor
- SINORHIZOBIUM MELILOTISinorhizobium melilotit0symbiont
- Outcome
- shoot height, root lengthe7
- Direction
- increasede7
- Qualifier
- in all water stress levelse7
- Comparator
- non-inoculated controle7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“the plants inoculated with Sm2011 and O152 strains increased shoot height, root length, shoot and root dry weights and formed the most efficient symbiotic couples compared to the other strains and non-inoculated control in all water stress levels”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
Inoculation with Sm2011 and O152 strains increased alfalfa shoot and root dry weights under all water stress levels.
- Taxon
- ALFALFAMedicago sativat0
- Treatment
- inoculated with Sm2011 and O152 strainse7
- Interactor
- SINORHIZOBIUM MELILOTISinorhizobium melilotit0symbiont
- Outcome
- shoot and root dry weightse7
- Direction
- increasede7
- Qualifier
- in all water stress levelse7
- Comparator
- non-inoculated controle7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“the plants inoculated with Sm2011 and O152 strains increased shoot height, root length, shoot and root dry weights and formed the most efficient symbiotic couples compared to the other strains and non-inoculated control in all water stress levels”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
Inoculation with Sm2011 and O152 strains formed the most efficient symbiotic couples with alfalfa.
- Taxon
- ALFALFAMedicago sativat0
- Treatment
- inoculated with Sm2011 and O152 strainse7
- Interactor
- SINORHIZOBIUM MELILOTISinorhizobium melilotit0symbiont
- Outcome
- symbiotic couplese7
- Direction
- most efficiente7
- Comparator
- the other strainse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“the plants inoculated with Sm2011 and O152 strains increased shoot height, root length, shoot and root dry weights and formed the most efficient symbiotic couples compared to the other strains and non-inoculated control in all water stress levels”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
Under severe water stress, a significantly higher nodule number was obtained with O152 and Sm2011 strains.
- Taxon
- ALFALFAMedicago sativat0
- Treatment
- severe stresse0
- Interactor
- SINORHIZOBIUM MELILOTISinorhizobium melilotit0symbiont
- Outcome
- nodule numbere0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under severe stress, a significantly higher nodule number was obtained with the O152 and Sm2011 strains”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
Under moderate water stress, strains Sm2011 and Sm1021 gave the best alfalfa nodulation.
- Taxon
- ALFALFAMedicago sativat0
- Treatment
- moderate stresse0
- Interactor
- SINORHIZOBIUM MELILOTISinorhizobium melilotit0symbiont
- Outcome
- nodulatione0
- Direction
- beste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under moderate stress, strains Sm2011, Sm1021 had the best nodulation”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
Inoculation under water stress significantly affected alfalfa nodule numbers; direction not stated.
- Taxon
- ALFALFAMedicago sativat0
- Treatment
- Inoculation under water stresse0
- Interactor
- SINORHIZOBIUM MELILOTISinorhizobium melilotit0symbiont
- Outcome
- nodule numberse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation under water stress was found to significantly affect nodule numbers of alfalfa”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
Combining alfalfa with rhizobial strains of superior water stress tolerance is an effective strategy to improve alfalfa productivity in drought areas.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- combining alfalfa and rhizobial strains with superior water stress tolerancee0
- Outcome
- improve alfalfa productivitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“combining alfalfa and rhizobial strains with superior water stress tolerance is an effective strategy to improve alfalfa productivity in drought affected areas”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
Claim · model-written summary
Tested alfalfa rhizobial strains were closely related to reference S. meliloti USDA 1002T, at 97.76% and 98.07% similarity for glnII and recA.
- Taxon
- ALFALFAMedicago sativat0
- Interactor
- tested strainse0symbiont
- Outcome
- similarity levele0
- Value
- 97.76 and 98.07%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phylogenetic analysis of concatenated sequences of glnII and recA showed that tested strains were closely related to reference strain S. meliloti USDA 1002T at similarity level of 97.76 and 98.07%, respectively”
t0“ALFALFA GROWTH UNDER WATER STRESS BY INOCULATION WITH SINORHIZOBIUM MELILOTI”
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