Optimizing phosphorus fertilization promotes dry matter accumulation and P remobilization in oilseed flax.

Xie, Y.P., Niu, J., Gan, Y.T., Gao, Y.H., and Li, A.R. (2014). "Optimizing phosphorus fertilization promotes dry matter accumulation and P remobilization in oilseed flax.", Crop Science, 54(4), pp. 1729-1736. doi : 10.2135/cropsci2013.10.0672  Access to full text

Abstract

Improving nutrient management is critical to increase nutrient use efficiency, promote translocation of photoassimilates to sinks, and increase crop yield. In this study, we determined the effects of phosphorus (P) fertilization on dry matter (DM) and P accumulation, partitioning and remobilization from vegetative tissues to the grains in oilseed flax (Linum usitatissimum L.). We hypothesized that P accumulation and remobilization depended on the level of P supply and varied with vegetative tissues. The cultivar Baxuan 3 was sown under low P (LP, 15 kg P ha1), moderate P (MP, 30 kg P ha1), and high P (HP, 45 kg P ha1) conditions along with a zero P control in a randomized complete block design, with three replicates, in 2011 and 2012. At mid-anthesis, leaf DM (average 1970 kg ha1) and stem DM (average 1826 kg ha1) were more than 20 times that of the nongrain reproductive DM (77 kg ha1); as plants grew to maturity, the DM in the stem and nongrain reproductive parts increased but leaf DM decreased. Compared with the control, oilseed flax grown under the LP, MP, and HP conditions increased leaf DM by 76%, stem DM by 46%, nongrain reproductive DM by 39%, and improved grain yield by an average of 45%. The fertilized oilseed flax increased the P translocation from vegetative tissues to the grains by 150% in 2011 and 201% in 2012. The P content in leaves reached the peak at anthesis and then decreased rapidly to maturity, whereas P contents in the stem and nongrain reproductive parts increased gradually and reached the peak at maturity, showing that leaves are the major contributor to the grain P, whereas the stem and nongrain reproductive parts are stronger P-demanding organs in oilseed flax. We suggest that advanced techniques, such as 32P labeling, may be used to further quantify the amount of P remobilized from the stems and nongrain reproductive parts to the grain.

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