Nutrient Acquisition by Soybean Treated with and without Silicon under Ultraviolet-B Radiation.

The objective of this study was to determine if treatment with silicon (Si) may improve nutrient uptake by soybean under ultraviolet-B (UV-B) radiation stress. Soybean (Glycine max L.) cultivars, 'Kennong 18' (K 18) and 'Zhonghuang 13' (ZH 13), were grown in hydroponic cultures under ambient and supplemental levels of ultraviolet-B (UV-B, 280-315 nm) with and without Si. Supplemental UV-B radiation simulating 30% stratospheric ozone depletion significantly decreased plant biomass by 74.9 to 135.6%, increased leaf nitrogen (N) and phosphorus (P) by 9% and 16%, respectively, decreased leaf magnesium (Mg) contents by 9%, and calcium (Ca) by 24%. UV-B radiation caused a substantial increase in the allocation of P, potassium (K) and Ca to roots compared with stem and leaves, presumably to ensure sustained nutrient uptake under the stress. Silicon application improved the uptake of P and Mg by 11%, which favored the partitioning of dry mass to shoots under UV-B radiation and the allocation of tissue P and Ca to roots. The overall changes due to Si supported a reasonable increase in dry mass of the 'K 18' cultivar. [ABSTRACT FROM AUTHOR]