Differential interactive effects of the Ca/Mg quotient and PEG-simulated drought in Alyssum inflatum and Fortuynia garcinii
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Background and aims
Serpentine soils typically have low Ca/Mg quotients, low water-holding capacities, and are rich in Ni and Cr, but poor in N and P. To better understand the role of drought and low Ca/Mg quotients in plant adaptation to serpentine soil, we compared the effects of different Ca/Mg quotients (0.18, 2 and 4) and polyethyleneglycol (PEG)–imposed osmotic stress on growth and Ca and Mg uptake and translocation between two Iranian serpentine endemic plant species, the Ni-hyperaccumulator Alyssum inflatum, and the non-accumulator Fortuynia garcinii.
Seedlings were grown in modified Hoagland’s solution with varying Ca/Mg molar quotients (0.18, 2 and 4) and then exposed to PEG (209.7 g L−1) for 8 days.
In both species, shoot dry weight was highest at the highest Ca/Mg quotient (4). However, at this Ca/Mg quotient A. inflatum suffered much more from PEG-induced drought (84% mortality and severe growth inhibition in the survivors), compared with the lower Ca/Mg quotients (<20% mortality and no significant growth inhibition). In F. garcinii, the PEG*Ca/Mg interaction was not significant. Shoot Ca concentrations and translocation factors in A. inflatum were higher than in F. garcinii in all the treatments. In both species the Mg translocation factor was highest at the highest Ca/Mg quotient (4) in the PEG treatment.
We conclude that a high Ca/Mg quotient stimulated growth in the absence of PEG in both species, but strongly decreased survival and growth in combination with PEG in A. inflatum. In F. garcinii root dry weight and the root to shoot dry weight ratio were significantly decreased at the highest Ca/Mg quotient (4), particularly after PEG treatment, suggesting that F. garcinii also may require a moderate or low Ca/Mg quotient to cope with natural drought.
KeywordsSerpentine soil Ca/Mg quotients Osmotic stress Uptake Translocation
We would like to thank the Graduate School of University of Isfahan for providing research facilities. We also thank Plant Antioxidants Center of Excellence (PACE) University of Isfahan for its support of this study.
- Boyd RS, Martens SN (1992) The raison d’être for metal hyperaccumulation by plants. In: AJM B, Proctor J, Reeves RD (eds) The ecology of ultramaffic (serpentine) soils. Intercept, Andover, pp 279–289Google Scholar
- Brooks RR (1987) Serpentine and its vegetation: a multidisciplinary approach. Dioscorides Press, Portland, OregonGoogle Scholar
- Ghasemi R, Chavoshi ZZ, Ghaderian SM (2015a) Stenocalcic properties in the serpentine-endemic plant Alyssum inflatum Nyárády. Aust JBot 63:31–38Google Scholar
- Ghasemi R, Chavoshi ZZ, Boyd RS, Rajakaruna N (2015b) Calcium: magnesium ratio affects environmental stress sensitivity in the serpentine-endemic Alyssum inflatum (Brassicaceae). Aust J Bot 63:39–46Google Scholar
- Ghasemi R, Share H, Sharifi R, Boyd RS, Rajakaruna N (2018) Inducing Ni sensitivity in the Ni hyperaccumulator plant Alyssum inflatum Nyárády (Brassicaceae) by transforming with CAX1, a vacuolar membrane calcium transporter. Ecol Res (in press)Google Scholar
- Goodwin-Bailey C, Woodell S, Loughman B (1992) The response of serpentine, mine spoil and saltmarsh races of Armeria maritima (mill.) Willd. To each others’ soils, the vegetation of ultramafic (serpentine) soils. Proceedings of the First International Conference on Serpentine Ecology, Hampshire, Intercept Ltd, p 390Google Scholar
- Harrison S, Rajakaruna N (2011) Serpentine: the evolution and ecology of a model system. Univ. of California Press, BerkeleyGoogle Scholar
- Kachenko AG (2008) A role for nickel in drought resistance in water-stressed Hybanthus floribundus subsp. floribundus. PhD thesis, Univ. of Sydney, pp. 1–20Google Scholar
- Pandey R, Agarwal RM (1998) Water stress-induced changes in proline contents and nitrate reductase activity in rice under light and dark conditions. Physiol Mol Biol Plants 4:53–57Google Scholar
- Rajakaruna N, Boyd R (2008) The edaphic factor. In ‘Encyclopedia of ecology. Vol. 2’.(eds Jorgensen SE, Fath B) Elsevier, Oxford, pp 1201–1207Google Scholar
- Salehi Eskandari B, Ghaderian SM, Schat H (2017b) The role of nickel (Ni) and drought in serpentine adaptation: contrasting effects of Ni on osmoprotectants and oxidative stress markers in the serpentine endemic, Cleome heratensis, and the related non-serpentinophyte, Cleome foliolosa. Plant Soil 147:183–195CrossRefGoogle Scholar