Shoot and Root Traits are Associated with Varying Soil Phosphorus Supply in Chinese Cabbage

Purpose: Phosphorus (P) is an essential nutrient for crop growth. P absorption efficiency was closely correlated with the variety of crop traits. It is currently unclear how vegetable crops may adapt to various P circumstances. Methods: Twenty inbred lines of Chinese cabbage (Brassica rapa pekinensis) were grown in a culture room under conditions of high P (HP, 200 mg P kg^− 1) and low P (LP, 20 mg P kg^− 1) to evaluate root traits in order to define various adaptive strategies in relation to P acquisition in vegetable crops. Under HP and LP conditions, the shoot dry weight of inbred lines with all above or below that average mean were mentioned as high-P efficiency (PE) or low-PE inbred lines, respectively. Results: HP condition enhanced the shoot and root dry weight and P content. The high-PE inbred lines had more advantages in terms of root length, root surface area, fine root length, and acid phosphatase activity when compared to the low-PE inbred lines. Low-PE inbred lines might exhibit greater adaptability in root physiological traits under LP conditions. Significant correlations among these traits were observed in our research. Meantime, strong co-variation of root traits was demonstrated regardless of P levels, the co-variation of shoot and root traits were demonstrated under LP condition. Conclusion: Low P affected the plasticity of root traits of Chinese cabbage.The high-PE inbred lines of Chinese cabbage tend to have stronger root traits in order to acquire more P. Acid phosphatase also acts synergistically with these root traits under LP condition. The low-PE inbred lines of Chinese cabbage may be dependent on adjustments to physiological traits to enhance P availability in rhizosphere soil. Under LP condition, we found that the co-variation between shoot and root traits helps for P acquisition. In future, P fertilizer management needs to be linked to the P acquisition strategies of Chinese cabbage.