Comprehensive evaluation of physiological traits under nitrogen stress and participation of linolenic acid in nitrogen-deficiency response in wheat seedlings.

Background: Nitrogen (N) deficiency is a major constraint for plant production in many areas. Developing the new crop genotypes with high productivity under N deficiency is an important approach to maintain agricultural production. Therefore, understanding how plant response to N deficiency and the mechanism of N-deficiency tolerance are very important for sustainable development of modern crop production.
Results: In this study, the physiological responses and fatty acid composition were investigated in 24 wheat cultivars under N-deficient stress. Through Pearson's correlation analysis and principal component analysis, the responses of 24 wheat cultivars were evaluated. The results showed that the plant growth and carbohydrate metabolism were all differently affected by N deficiency in all tested wheat cultivars. The seedlings that had high shoot biomass also maintained high level of chlorophyll content under N deficiency. Moreover, the changes in fatty acid composition, especially the linolenic acid (18:3) and the double bond index (DBI), showed close positive correlations with the shoot dry weight and chlorophyll content alterations in response to N-deficient condition. These results indicated that beside the chlorophyll content, the linolenic acid content and DBI may also contribute to N-deficiency adaptation, thus could be considered as efficient indicators for evaluation of different response in wheat seedlings under N-deficient condition.
Conclusions: The alteration in fatty acid composition can potentially contribute to N-deficiency tolerance in plants, and the regulation of fatty acid compositions maybe an effective strategy for plants to adapt to N-deficient stress.