Fig. 10.

Effects of wheat straw addition on the content and distribution of lignin in watermelon roots. PAL activity (a) and POD activity (b) in watermelon roots. Cross-sections of the main roots of watermelon at flowering stage, stained with Safranin O (red) and Fast green FCF (green) (c). Arrows indicate the lignin distribution in watermelon roots. Magnification = 4400×. The lignin conent in watermelon roots (d). CK, without adding wheat straw; T1, addition of 1% wheat straw; T2, addition of 2% wheat straw