Abstract
Abstract A 130-day hydroponic experiment was carried out in a glasshouse to examine whether manganese (Mn) concentration in the nutrient solution affects the nutritional status of olive plants and to find out whether the chlorophyll fluorescence technique is suitable to assess Mn toxicity and/or deficiency stress in olive plants prior to the appearance of these two nutritional disorders. For this purpose, chlorophyll fluorescence parameters (Fv/Fm and Fv/F0 ratios) were recorded every 40 days in the leaves of 'Kothreiki' and 'FS-17' olive cultivars, which were irrigated with Hoagland's nutrient solutions containing various Mn concentrations. In parallel the elongation of the main shoot of all experimental plants, as well as the concentrations of Mn, iron (Fe), zinc (Zn), boron (B), phosphorus (P), calcium (Ca), magnesium (Mg), and potassium (K) in their leaves were recorded. The following Mn treatments were applied: 0 μM Mn (to induce Mn deficiency), 40 μM Mn (to promote normal growth), and 640 μM Mn (to induce Mn toxicity). Our results indicated that not only the rate of shoot elongation but also the fluctuation with time of the leaf concentrations of all determined mineral elements (except for Mn) was not significantly affected by the Mn concentration in the nutrient solution, irrespectively of the cultivar. This was not observed with regard to the time variation of the Fv/Fm and Fv/F0 ratios, where the values of these parameters were significantly reduced in the 640 μM Mn treatment at the 80th and 130th day of the experiment in both olive cultivars, compared to the relevant previous ones (those of the days 0 and 40th), something which did not happen in the other two Mn treatments (0 and 40 μM). However, in none of the two cultivars tested and in any of the three Mn treatments (0, 40 and 640μM) the Fv/Fm and Fv/F0 ratios did not drop below the critical values of 0.8 and 4, respectively, even at the end of the experiment, where high Mn concentrations were found in the leaves of both cultivars treated with 640 μM Mn (616 μg g−1 d.w. in 'FS-17' and 734 μg g−1 d.w. in 'Kothreiki'). Symptoms of Mn toxicity (curling and brown speckles) were observed in the top leaves of both cultivars, after the 90th day of the experiment. At the same time, the final leaf Mn concentrations (those of the 130th day of the experiment) in plants grown under 0 μM Mn were 23 μg g−1 d.w. in 'FS-17' and 20 μg g−1 d.w. in 'Kothreiki', i.e., a little above of the deficiency range (<20 μg g−1 d.w.). At the 130th day, Mn concentration in nutrient solution, as well as Mn concentration in the leaves of both olive cultivars was negatively correlated with the leaf concentration of Fe and the values of the Fv/Fm and Fv/F0 ratios, and positively with the concentrations of Zn and P in the leaves. Finally, the periodical measurement of the Fv/Fm and Fv/F0 ratios was proved to be a non-reliable means to predict the appearance of the visible symptoms of Mn toxicity in olive leaves (although their values declined significantly at the 80th and 130th day of the experiment in both olive cultivars). Keywords: chlorophyll fluorescencemanganesephotosystem IIolive cultivarsdeficiencytoxicity ACKNOWLEDGMENTS We would like to thank Mrs. Sofia Kouti and Mrs. Vasiliki Tsakiridou for their assistance in chemical analyses.
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Claims 14
Claim · model-written summary
Manganese treatment did not significantly affect shoot elongation rate.
- Taxon
- olive
Olea europaeae1 - Treatment
- Mn concentration in the nutrient solutione0
- Outcome
- rate of shoot elongatione0
- Direction
- not significantly affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the rate of shoot elongation but also the fluctuation with time of the leaf concentrations of all determined mineral elements (except for Mn) was not significantly affected by the Mn concentration in the nutrient solution, irrespectively of the cultivar”
e1“'Kothreiki' and 'FS-17' olive cultivars”
Claim · model-written summary
Manganese treatment did not significantly affect temporal variation of leaf minerals other than Mn.
- Taxon
- oliveOlea europaeae1
- Treatment
- Mn concentration in the nutrient solutione0
- Outcome
- fluctuation with time of the leaf concentrations of all determined mineral elements (except for Mn)e0
- Direction
- not significantly affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the fluctuation with time of the leaf concentrations of all determined mineral elements (except for Mn) was not significantly affected by the Mn concentration in the nutrient solution, irrespectively of the cultivar”
e1“'Kothreiki' and 'FS-17' olive cultivars”
Claim · model-written summary
At 640 μM Mn, Fv/Fm and Fv/F0 fell at days 80 and 130 versus earlier days in both cultivars.
- Taxon
- oliveOlea europaeae0
- Treatment
- 640 μM Mn treatmente0
- Outcome
- Fv/Fm and Fv/F0 ratiose0
- Direction
- significantly reducede0
- Comparator
- days 0 and 40the0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fv/Fm and Fv/F0 ratios, where the values of these parameters were significantly reduced in the 640 μM Mn treatment at the 80th and 130th day of the experiment in both olive cultivars, compared to the relevant previous ones (those of the days 0 and 40th)”
Claim · model-written summary
At 0 and 40 μM Mn, the fluorescence ratio decline seen at 640 μM did not occur.
- Taxon
- oliveOlea europaeae2
- Treatment
- 0 and 40 μMe0
- Outcome
- Fv/Fm and Fv/F0 ratiose1
- Direction
- did not happene0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“something which did not happen in the other two Mn treatments (0 and 40 μM)”
e1“time variation of the Fv/Fm and Fv/F0 ratios”
e2“'Kothreiki' and 'FS-17' olive cultivars”
Claim · model-written summary
Neither cultivar crossed the critical Fv/Fm or Fv/F0 thresholds in any treatment.
- Taxon
- oliveOlea europaeae1
- Outcome
- Fv/Fm and Fv/F0 ratios did not drop below the critical values of 0.8 and 4e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in none of the two cultivars tested and in any of the three Mn treatments (0, 40 and 640μM) the Fv/Fm and Fv/F0 ratios did not drop below the critical values of 0.8 and 4, respectively”
e1“'Kothreiki' and 'FS-17' olive cultivars”
Claim · model-written summary
At 640 μM Mn, FS-17 leaf Mn reached 616 μg g−1 dry weight.
- Taxon
- oliveOlea europaeae1
- Material
- FS-17e0
- Outcome
- Mn concentrationse2
- Value
- 616 μg g−1 d.w.e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“616 μg g−1 d.w. in 'FS-17'”
e1“'Kothreiki' and 'FS-17' olive cultivars”
e2“high Mn concentrations were found in the leaves”
Claim · model-written summary
At 640 μM Mn, Kothreiki leaf Mn reached 734 μg g−1 dry weight.
- Taxon
- oliveOlea europaeae1
- Material
- Kothreikie0
- Outcome
- Mn concentrationse2
- Value
- 734 μg g−1 d.w.e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“734 μg g−1 d.w. in 'Kothreiki'”
e1“'Kothreiki' and 'FS-17' olive cultivars”
e2“high Mn concentrations were found in the leaves”
Claim · model-written summary
Both cultivars developed toxicity symptoms in top leaves after day 90.
- Taxon
- oliveOlea europaeae1
- Organ / stage
- top leavese0
- Outcome
- Symptoms of Mn toxicity (curling and brown speckles)e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Symptoms of Mn toxicity (curling and brown speckles) were observed in the top leaves of both cultivars, after the 90th day of the experiment”
e1“'Kothreiki' and 'FS-17' olive cultivars”
Claim · model-written summary
Under 0 μM Mn, FS-17 leaf Mn was 23 μg g−1 dry weight on day 130.
- Taxon
- oliveOlea europaeae1
- Material
- FS-17e0
- Outcome
- leaf Mn concentrationse2
- Value
- 23 μg g−1 d.w.e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“23 μg g−1 d.w. in 'FS-17'”
e1“'Kothreiki' and 'FS-17' olive cultivars”
e2“final leaf Mn concentrations”
Claim · model-written summary
Under 0 μM Mn, Kothreiki leaf Mn was 20 μg g−1 dry weight on day 130.
- Taxon
- oliveOlea europaeae1
- Material
- Kothreikie0
- Outcome
- leaf Mn concentrationse2
- Value
- 20 μg g−1 d.w.e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“20 μg g−1 d.w. in 'Kothreiki'”
e1“'Kothreiki' and 'FS-17' olive cultivars”
e2“final leaf Mn concentrations”
Claim · model-written summary
Solution and leaf Mn were negatively correlated with leaf Fe at day 130.
- Taxon
- oliveOlea europaeae0
- Compound
- Mne0
- Outcome
- leaf concentration of Fee0
- Direction
- negatively correlatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mn concentration in nutrient solution, as well as Mn concentration in the leaves of both olive cultivars was negatively correlated with the leaf concentration of Fe”
Claim · model-written summary
Solution and leaf Mn were negatively correlated with fluorescence ratios at day 130.
- Taxon
- oliveOlea europaeae0
- Compound
- Mne0
- Outcome
- values of the Fv/Fm and Fv/F0 ratiose0
- Direction
- negatively correlatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mn concentration in nutrient solution, as well as Mn concentration in the leaves of both olive cultivars was negatively correlated with the leaf concentration of Fe and the values of the Fv/Fm and Fv/F0 ratios”
Claim · model-written summary
Solution and leaf Mn were positively correlated with leaf Zn and P.
- Taxon
- oliveOlea europaeae0
- Compound
- Mne0
- Outcome
- concentrations of Zn and P in the leavese0
- Direction
- positivelye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mn concentration in nutrient solution, as well as Mn concentration in the leaves of both olive cultivars was negatively correlated with the leaf concentration of Fe and the values of the Fv/Fm and Fv/F0 ratios, and positively with the concentrations of Zn and P in the leaves”
Claim · model-written summary
Periodic fluorescence ratio measurement was unreliable for predicting visible Mn toxicity symptoms.
- Taxon
- oliveOlea europaeae0
- Outcome
- non-reliable means to predict the appearance of the visible symptoms of Mn toxicitye0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the periodical measurement of the Fv/Fm and Fv/F0 ratios was proved to be a non-reliable means to predict the appearance of the visible symptoms of Mn toxicity in olive leaves”
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