Phytoremediating coastal saline soils with oats: accumulation and distribution of sodium, potassium, and chloride ions in plant organs

Saline soil is considered to have a greater reserve of potentially cultivable land in China, especially in coastal areas with abundant rainfall. The possible use of oats (Avena sativa L. or Avena nuda L) for phytoremediation of the salinity and thus to improve soil quality for other crops is receiving greater attention. Six varieties (Bayou-1, Baiyan-2, Baiyan-7, Huawan-6, Huazao-2 and Pin-16) of oat were studied for their accumulation and distribution of salt ions in plant organs using a saline coastal area near the Bohai sea of North China. The objective was to determine the effects of variety, plant organs and time of harvest on the phytoremediating potential of oat. Plant uptake of sodium, potassium and chloride ions as well as growth rate varied significantly according to variety, growth stage, plant organ, and their interactions. The peak uptake of sodium and chloride ions in leaves across varieties was at the heading stage but in stem it was at maturity; for most varieties, potassium concentration was much higher in the stem during the growth period. The partitioning of ions to stem, root and panicle increased from heading to maturity but declined from maturity to delayed harvesting stage. However, those in the leaf continually decreased from heading to delayed harvesting stage. Averaged across growth stages and organs, the highest uptake rate for sodium ion (1739.4 g ha(-1) day(-1)) and chloride ion (3693.7 g ha(-1) day(-1)) was in the stem of BaiYan-7 variety during heading to maturity. The uptake rates for potassium ion in the stem were also the highest (2880.2 g ha(-1) day(-1) in the stem of BaiYan-2 variety) but they occurred from elongation to heading stage. Since most of the ions were concentrated in the straw, especially the stem, managing oats to enhance stem or straw biomass production and optimizing harvest or clipping times would have both economic and remediation benefits. Data from this study have added new information on how best to use oat for reclaiming degraded saline soils. (C) 2014 Elsevier Ltd. All rights reserved.