FIGURE 4 The root system secretes catalase activity in the
culture medium. (a), (b), and (c) respectively represent the changes in
catalase under the superimposed environmental factors of nitrogen,
phosphorus and nitrogen-phosphorus deficit stress. (d) indicates the
changes in catalase under the superimposed drought and high temperature.
* indicating a significant difference to the N, P, NP, D, and CK
treatment, p < 0.05.