Effects of K-deficiency stress on the root morphology and nutrient efficiency of sugarcane

Potassium (K) deficiency in soil restricts the production of sugarcane in major planting areas. To investigate the responses of sugarcane varieties to K-deficiency stress, the growth, root parameters, and nutrient-use efficiency of sugarcane varieties were compared using sand cultures. K deficiency inhibited the growth of sugarcane. Two hybrid sugarcane varieties, namely YC10–29 and YC10–65, exhibited greater tolerance to K-deficiency stress. The weight, length, surface area, and volume of root showed 30.49%, 15.91%, 20.02%, and 24.26% reductions, respectively, in ROC22 under K-deficiency stress, but increased in the other five varieties. YC10–65 accumulated 2.03 times more nitrogen (N) in the roots than did the plants under normal conditions. Significant increases for N and phosphorous (P) utilization efficiencies were detected in YC10–65 under K-deficiency stress. Correlations between nutrient efficiency and root morphology revealed that modifications to root morphology in response to K deficiency may help improve the nutrient efficiency and the K-deficiency tolerance of sugarcane.