Ancient and improved wheats are discrepant in nitrogen uptake, remobilization, and use efficiency yet comparable in nitrogen assimilating enzymes capabilities

摘要

Since clarity is lacking around nitrogen (N) acquiring and partitioning in ancient wheats of different ploidy levels, N uptake, remobilization, utilization, use efficiency, and assimilation of these wheats was assessed. A twoyear field experiment and one pot experiment were conducted on some less-improved free-threshing durum and hulled einkorn, emmer, spelt, and macha wheats and improved free-threshing durum and bread wheats. This study compared di-, tetra-, and hexaploid wheats of modern and old types under a range of N fertilization levels. N fertilizer was applied to the examined wheats at the 0 - 120 kg ha(-1) N rates to achieve various N supplies/deficiencies. Ancient wheats were unresponsive to N supply, as evidenced by smaller N uptake, utilization, remobilization, use efficiency, grain yield, and harvest index compared to the improved durum and bread wheats particularly in the presence of sufficient N supplies. Though, the N-deprived ancient wheats such as emmer wheats tended to indicate greater or comparable N uptake and utilization efficiencies, in comparison to the improved durum and bread wheats. The activity of nitrate reductase, nitrite reductase, and glutamine synthetase of the ancient wheats was not meaningfully different from the improved durum and bread ones. Some of these ancient wheats possessed a greater or at least comparable DM production under low N input conditions and their grain protein concentration was notably greater than the improved wheats across the wide range of N supplies attempted herein. Novel findings of this study define ancient wheats such as emmer, spelt, and macha lowyielding and unresponsive to N but capable of acquiring and utilizing N from N deficient medium and a potential alternative/specialty species for low-input production systems.