Differential Cl−/Salt Tolerance and NaCl-Induced Alternations of Tissue and Cellular Ion Fluxes in Glycine max, Glycine soja and their Hybrid Seedlings

Abstract

The salt‐sensitive Glycine max N23674 cultivar, the salt‐born Glycine soja BB52 population, and their hybrid 4076 strain (F5) selected for salt tolerance generation by generation were used as the experimental materials in this study. First, the effects of NaCl stress on seed germination, tissue damage, and time‐course ionic absorption and transportation were compared. When qualitatively compared with seed germination appearance in culture dishes, and tissue damages on roots or leaves of seedlings, or quantitatively compared with the relative salt injury rate, the inhibition on N23674 was all the most remarkable. After the exposure of 140 mm NaCl for 1 h, 4 h, 8 h, 12 h, 2 days and 4 days, the content of Cl− gradually increased in the roots and leaves of seedlings of BB52, 4076 and 23674. Interestingly, the extents of the Cl− rise in roots of the three experimental soybean materials were BB52 > 4076 > N23674, whereas those in leaves were just on the contrary. Secondly, by using the scanning ion‐selective electrode technique (SIET), fluxes of Na+ and Cl− in roots and protoplasts isolated from roots and leaves were also investigated among the three experimental soybean materials. After 140 mm NaCl stress for 2, 4 and 6 days, and when compared with N23674, slighter net Cl− influxes were observed in root tissue and protoplasts of roots and leaves of BB52 and 4076 seedlings, especially at the cellular protoplast level. The results indicate that with regard to the ionic effect of NaCl stress, Cl− was the main determinant salt ion for salt tolerance in G. soja, G. max and their hybrid, and the difference in their Cl−/salt tolerance is mainly attributed to the capacity of Cl− restriction to the plant above‐ground parts such as leaves.

Crescimento e acúmulo de íons em plantas de cajueiro anão precoce em diferentes tempos de exposição à salinidade

“…A tolerância das plantas à salinidade requer, dentre vários fatores, a compartimentação de íons Na + e Cl -nos tecidos, a níveis intra/extracelular, a fim de evitar concentrações tóxicas dentro do citoplasma, especialmente nas células do mesofilo foliar (ZHANG et al, 2011 A tolerância das plantas à salinidade requer, dentre vários fatores, a compartimentação de íons Na + e Cl -nos tecidos, a níveis intra/extracelular, a fim de evitar concentrações tóxicas dentro do citoplasma, especialmente nas células do mesofilo foliar (ZHANG et al, 2011). Na maioria das culturas, tais como algodão, feijão, trigo e arroz, o Na + parece contribuir mais do que o Cl -para a toxidez em plantas sob estresse salino.…”

“…Na maioria das culturas, tais como algodão, feijão, trigo e arroz, o Na + parece contribuir mais do que o Cl -para a toxidez em plantas sob estresse salino. Contudo, existem estudos que demonstram que algumas culturas (soja e citros, por exemplo) são mais sensíveis ao Cl -do que ao Na + (BRUMÓS et al, 2009;LUO;LIU, 2005;ZHANG et al, 2011).…”

“…Em um estudo realizado com cultivares e híbridos provenientes desses cultivares de soja tolerantes à salinidade, Zhang et al (2011) observaram um maior aumento no influxo celular de Cl -e Na + nas raízes e folhas das plantas sensíveis com o prolongamento do tempo de estresse salino, enquanto que nas plantas tolerantes ocorreu um efluxo de Na + , associado a um menor influxo de Cl -. Para esses autores, as diferenças de tolerância à salinidade entre cultivares e híbridos de soja são atribuídas principalmente à capacidade da planta de restringir o acúmulo dos íons Cl -na parte aérea, especialmente nas folhas.…”

Enhancing NO3- supply confers NaCl tolerance by adjusting Cl- uptake and transport in G. max & G. soja

“…The absorbed nitrogen for plants utilization includes various N forms (nitrate, ammonium, amino acids, and peptides), and nitrate (NO 3 -) is the most important nitrogen source for plants (Chen et al, 2012), and is also the main mineral and univalent anions in plant tissues and cells except Cl -, 2010). Studies have showed that, tobacco, grape, potato, citrus and soybean, whose salt stress effects are mainly caused by Cl -, are known as the "chloridehating plants" (Zhang et al, 2011, Abbaspour et al, 2013, Henderson et al, 2014. Cultivated soybean (G. max) is one of the important grain and oil crops in the world, wild soybean (G. soja) is the relative of G. max, and is often regarded as an important genetic germplasm resource for high yield and good quality of G. max breeding (Zhang et al, 2011).…”

“…Studies have showed that, tobacco, grape, potato, citrus and soybean, whose salt stress effects are mainly caused by Cl -, are known as the "chloridehating plants" (Zhang et al, 2011, Abbaspour et al, 2013, Henderson et al, 2014. Cultivated soybean (G. max) is one of the important grain and oil crops in the world, wild soybean (G. soja) is the relative of G. max, and is often regarded as an important genetic germplasm resource for high yield and good quality of G. max breeding (Zhang et al, 2011).…”