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Does high pH give a reliable assessment of the effect of alkaline soil on seed germination? A case study with Leymus chinensis (Poaceae)

journal contribution
posted on 2024-11-16, 07:37 authored by Hongyuan Ma, Haoyu Yang, Xiaotao Lü, Yuepeng Pan, Haitao Wu, Zhengwei Liang, Mark Ooi
Background and aims Alkaline soils, characterized by high pH, are representative of degraded regions throughout the world. Studying germination in relation to alkalinity can contribute to understanding how species cope with such conditions. Although the effects of pH have been widely studied, it is unknown whether germination response to pH gradients created with buffer solutions is representative of the conditions experienced in alkaline soils. Our aims were to (1) determine if high pH gives an accurate assessment of the effects of alkaline soils on germination, and (2) identify the inhibitory factors for germination in alkaline soils. Methods Using Leymus chinensis seeds, germination was tested over a gradient of pH solutions prepared using Tris (50 mM and 100 mM) and H2O buffers and eight germination media prepared from non-alkaline and alkaline soils with different pH and electrical conductivities (EC). Additionally, solutions of 10-100 mM NaCl, Na2SO4, Na2CO3 and NaHCO3 were used to determine the main ions inhibiting seed germination. Results H2O-buffered pH had no effect on seed germination, and seed germination was much lower at all pH levels in 50 mM Tris-HCl solutions (pH 7.0-10.35) than in the H2O control (pH 7.05). No seeds germinated in 100 mM Tris-HCl buffers irrespective of the pH. In alkaline germination media (pH 10.04-10.61), high germination was obtained only at low EC. The rank order of the inhibitory effect of salts was Na2CO3 > NaHCO3 > NaCl > Na2SO4. Conclusions Buffer solutions used to simulate alkaline environments did not provide a reliable indicator of the effects of alkaline soils on seed germination. High pH of alkaline soil had no negative effects, and results suggest that salt composition and concentration, especially CO3 2− and HCO3 −, are key inhibitors.

Funding

Predicting climate change impacts on biodiversity: testing and applying new approaches

Australian Research Council

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Citation

Ma, H., Yang, H., Lü, X., Pan, Y., Wu, H., Liang, Z. & Ooi, M. K. J. (2015). Does high pH give a reliable assessment of the effect of alkaline soil on seed germination? A case study with Leymus chinensis (Poaceae). Plant and Soil: international journal on plant-soil relationships, 394 (1-2), 35-43.

Journal title

Plant and Soil

Volume

394

Issue

1/02/2024

Pagination

35-43

Language

English

RIS ID

100770

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