Abstract
The tolerance of lettuce plants (Lactuca sativa L. cv. Romana) to drought stress differed with the arbuscular-mycorrhizal fungal isolate with which the plants were associated. Seven fungal species belonging to the genus Glomus were studied for their ability to enhance the drought tolerance of lettuce plants. These fungi had different traits that affected the drought resistance of host plants. The ranking of arbuscular-mycorrhizal fungal effects on drought tolerance, based on the relative decreases in shoot dry weight, was as follows: Glomus deserticola > Glomus fasciculatum > Glomus mosseae > Glomus etunicatum > Glomus intraradices > Glomus caledonium > Glomus occultum. In this comparative study specific mycorrhizal fungi had consistent effects on plant growth, mineral uptake, the CO(inf2) exchange rate, water use efficiency, transpiration, stomatal conductance, photosynthetic phosphorus use efficiency, and proline accumulation under either well-watered or drought-stressed conditions. The ability of the isolates to maintain plant growth effectively under water stress conditions was related to higher transpiration rates, levels of leaf conductance, and proline, N, and P contents. Differences in proline accumulation in leaves among the fungal symbioses suggested that the fungi were able to induce different degrees of osmotic adjustment. The detrimental effects of drought were not related to decreases in photosynthesis or water use efficiency. Neither of these parameters was related to P nutrition. The differences in P and K acquisition, transpiration, and stomatal conductance were related to the mycorrhizal efficiencies of the different fungi. Our observations revealed the propensities of different Glomus species to assert their protective effects during plant water stress. The greater effectiveness of G. deserticola in improving water deficit tolerance was associated with the lowest level of growth reduction (9%) under stress conditions. The growth of plants colonized by G. occultum was reduced by 70% after a progressive drought stress period. In general, the different protective effects of the mycorrhizal isolates were not associated with colonizing ability. Nevertheless, G. deserticola was the most efficient fungus and exhibited the highest levels of mycorrhizal colonization, as well as the greatest stimulation of physiological parameters.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 10
Claim · model-written summary
Glomus isolates differed in lettuce drought tolerance effects.
- Taxon
- lettuce plants
Lactuca sativae0 - Interactor
- arbuscular-mycorrhizal fungal isolatee0symbiont
- Outcome
- tolerancee0
- Direction
- differede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The tolerance of lettuce plants (Lactuca sativa L. cv. Romana) to drought stress differed with the arbuscular-mycorrhizal fungal isolate”
Claim · model-written summary
Glomus deserticola ranked highest and G. occultum lowest for drought protection based on shoot weight decline.
- Interactor
- Glomus deserticolaSeptoglomus deserticolae0symbiont
- Outcome
- relative decreases in shoot dry weighte0
Not reportedTaxonDirection
Verbatim
e0“The ranking of arbuscular-mycorrhizal fungal effects on drought tolerance, based on the relative decreases in shoot dry weight, was as follows: Glomus deserticola > Glomus fasciculatum > Glomus mosseae > Glomus etunicatum > Glomus intraradices > Glomus caledonium > Glomus occultum”
Claim · model-written summary
Plant growth maintenance under water stress related to higher transpiration and leaf conductance.
Not reportedTaxon
Verbatim
e0“The ability of the isolates to maintain plant growth effectively under water stress conditions was related to higher transpiration rates, levels of leaf conductance”
Claim · model-written summary
Plant growth maintenance under water stress related to higher proline, N and P contents.
Not reportedTaxon
Verbatim
e0“The ability of the isolates to maintain plant growth effectively under water stress conditions was related to higher transpiration rates, levels of leaf conductance, and proline, N, and P contents.”
Claim · model-written summary
Drought effects were not related to declines in photosynthesis or water use efficiency.
Not reportedTaxon
Verbatim
e0“The detrimental effects of drought were not related to decreases in photosynthesis or water use efficiency.”
Claim · model-written summary
Photosynthesis and water use efficiency were unrelated to P nutrition.
Not reportedTaxonDirection
Verbatim
e0“Neither of these parameters was related to P nutrition.”
Claim · model-written summary
P and K acquisition differed in relation to fungal mycorrhizal efficiency.
Not reportedTaxonDirection
Verbatim
e0“The differences in P and K acquisition, transpiration, and stomatal conductance were related to the mycorrhizal efficiencies of the different fungi.”
Claim · model-written summary
G. deserticola colonized lettuce had 9% growth reduction under drought.
- Taxon
- lettuce plantsLactuca sativat0
- Interactor
- G. deserticolaSeptoglomus deserticolae0symbiont
- Outcome
- growth reductione0
- Direction
- reductione0
- Value
- 9%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The greater effectiveness of G. deserticola in improving water deficit tolerance was associated with the lowest level of growth reduction (9%) under stress conditions.”
t0“lettuce plants (Lactuca sativa L. cv. Romana)”
Claim · model-written summary
G. occultum colonized lettuce had 70% growth reduction after progressive drought.
- Taxon
- plantsViridiplantaee0
- Interactor
- G. occultumParaglomus occultume0symbiont
- Outcome
- growthe0
- Direction
- reducede0
- Value
- 70%e0
Verbatim
e0“The growth of plants colonized by G. occultum was reduced by 70% after a progressive drought stress period.”
Claim · model-written summary
Protective effects of fungal isolates generally did not track colonizing ability.
Not reportedTaxonDirection
Verbatim
e0“the different protective effects of the mycorrhizal isolates were not associated with colonizing ability.”