Zinc uptake and transport in wild emmer and cultivated durum wheat differing in seed zinc concentrations

Official URL: http://plantnutrition.org/files/downloads/2013ipnc-b-proceedings.pdf

Root uptake and shoot translocation of Zn showed substantial variation among wheat species and genotypes. Cultivated durum wheat genotypes had about two-­‐fold higher Zn root uptake and root-to-shoot translocation rate. Among the wild emmer accessions TD 536 expressed the lowest and TD 678 expressed the highest Zn uptake and translocation. Uptake and translocation data correlated significantly (Table 1) suggesting that these traits are interdependent and rate of root Zn uptake defines rate of root-to-shoot Zn translocation during vegetative growth stage. Unlike root uptake and translocation, no correlation was found between Zn mobilization (from oldest leaf tip) to shoot and root (Table 1). There were, however, significant differences among emmer wheat accessions and durum wheat cultivars in root or shoot Zn mobilization. Neither the root nor the shoot Zn mobilization rates expressed a correlation with root uptake or shoot translocation of Zn (Table 1). Similarly, mobilization of Zn from flag leaf towards the grain also had no correlation with uptake, translocation or mobilization of Zn during vegetative growth stages (Table 1). With the exception of TTD 21, emmer wheat accessions in general expressed a significantly lower grain Zn mobilization rate compared to durum wheat cultivars. It was noted that the only positive and significant correlation of grain Zn mobilization was with grain yield (Table 1). In summary, the difference in seed (or grain) Zn concentration of wild emmer and cultivated durum wheats were not associated with dry matter production, shoot Zn concentration, root uptake, shoot translocation and root, shoot and grain Zn mobilization. There are apparently other factors involved in accumulation of high Zn in grains of wild emmer wheat accessions compared to cultivated wheat such as low grain yield and less number of seeds per spike which may contribute to a "Zn concentration effect” in wild emmer grains.