The High Metal Macronutrients Selectivity over Na+ of Puccinellia chinampoensis Ohwi in the Rhizosphere of Sodic Soil

Abstract

The uptake of metal macronutrients (K+, Ca2+, Mg2+) and Na+ of Puccinellia chinampoensis Ohwi (P. chinampoensis), a sodic tolerant plant, were investigated in both sodic and alkaline soil. In the first experiment, sodic soil was collected from Songnen Plain in Jilin Province in northeast China. P. chinampoensis, Festuca arundinacea Schreb. (F. arundinacea) and Dactylis glomerata L. (D. glomerata) were grown in the sodic soil in growth chamber under natural light, but the plants did not grow. Then, the plants were grown in sodic soil mixed with vermiculite (artificial soil). The plants grew, and P. chinampoensis and F. arundinacea showed better growth than D. glomerata in the artificial soil. P. chinampoensis showed higher K level than the other plants and maintained low Na level in the shoot. Besides, P. chinampoensis had tremendously low Na/K, Na/Ca, and Na/Mg ratios. In the properties of artificial soil, soil pH was similar to the original sodic soil which was over 10. However, the soil cation exchange capacity (soil CEC) was higher, and the soil electrical conductivity (soil EC) and exchangeable sodium percentage (ESP) were lower than the original sodic soil. In the second experiment, P. chinampoensis and Leymus chinensis [Trin.] Tzvelev (L. chinensis) were grown on natural alkaline area in the Songnen Plain. There were no significant differences of the Na, K, Ca, and Mg levels in the both plants. Especially, though the concentration of exchangeable K+ was more than double, K level of P. chinampoensis in the alkaline soil was about one-tenth of that in the artificial soil. It was concluded that P. chinampoensis had high selectivity of metal macronutrients over Na+ which functions in sodic soils. Besides, it seemed that high soil EC and exchangeable Na+ were more harmful than high soil pH for plant growth on sodic soils.