Changes in C, N, P content and stoichiometric ratios in response to salt stress in Avena sativa plants

This study investigated the effects of salt stress on C, N, and P distribution, and the stoichiometry of the oat, Avena sativa, providing a theoretical basis for the use of oats as a biological tool for the improvement of saline soil in the Hexi region. The content of C, N, and P, and the stoichiometric ratios of oat plants were studied under 5 kinds of salt concentration stress. Our results showed that: 1) With an increase in salt concentration, the content of C, N, and P in the aboveground and underground parts of oat increased and then decreased, reaching a maximum value at 150 mmol·L⁻¹. 2) Oats adapted to adversity stress primarily by changing the utilization efficiency of N and P. Under salt stress, the C∶N and C∶P ratios were lower in the aboveground regions of oat plants than in the underground parts. Meanwhile, the oat N∶P values (2.5～10.6) were all lower than 14. Compared to P, N showed a higher restriction in the growth of oats in the Hexi area. 3) There was a significant correlation between the conversion and utilization of aboveground and subsurface nutrients under salt stress (P < 0.05), and N was the most sensitive. In summary, 150 mmol·L⁻¹ was the maximum salt tolerance threshold of oats grown in the Hexi region. Reasonable nitrogen fertilizer addition was more conducive to oat growth as a biological tool for the improvement and restoration of saline grassland in the Hexi region.