Genotypic difference in response to Fe deficiency of winter wheat with different phosphorus efficiency

The genotypic differences in response to iron deficiency (-Fe) of winter wheat with different phosphorus efficiency were investigated in nutrient solution under controlled conditions. The genotypic differences existed in response to Fe deficiency, which decreased the shoot growth in P efficiency genotypes more significantly than in P inefficiency genotypes. Compared with supplying Fe treatment(+Fe), in -Fe treatment, the average biomass in shoot of three P efficiency genotypes, 81(85)-5-3-3-3、Xiaoyan54 and Taihe-5025 decreased by 55.2%, and that in three P inefficiency genotypes, Jinghe90-Jian-17、NC37 and Jing411 decreased by 33.0%. The different response to Fe deficiency also existed in chlorophyll content between P efficiency genotypes and P inefficiency genotypes. The average contents of three P efficiency genotypes in chlorophyll a、chlorophyll b and chlorophyll a+b decreased by 35.6%, 35.3% and 35.3%, respectively, more significantly than that in three P inefficiency ones by 16.8%, 7.7% and 11.9%. respectively.The Fe deficiency was not significant effect on root growth, P uptake in root and P utilization efficiency (dry matter production per unit of P uptake, g/mg), but decreased the root efficiency ratio (ratio of P uptake in shoot to dry matter, mg/g) and P uptake in shoot in P efficiency genotypes more significantly than in P inefficiency genotypes. The root efficiency ratio and P uptake in shoot in P efficiency genotypes and in P inefficiency genotypes decreased by 55.0%, 54.9% and 32.5%, 36.4% in Fe deficiency treatment respectively. The P accumulation in P efficiency genotypes is much more than that in P inefficiency which appears to be the causative factor of the P efficiency genotypes more sensitivity to Fe deficiency.