2.3.2. Total Phenolic Compounds Content

The elicitor effect of the sulfated polysaccharides studied (FSF and BBF) on phenolic metabolism was also approached by the accumulation of total phenols in treated roots. The accumulation of phenolic compounds following FSF and BBF treatments was presented in Figure 4. Roots elicitation by FSF caused a significant (*p* < 0.05) and intense accumulation of phenolic compounds after 24 h compared to the control treatment (Figure 4). Second narrower accumulation of phenols was approved after 72 h of FSF treatment, this could be explained by the induction of PAL activity at the same time. However, a precocious and significant (*p* < 0.05) accumulation of these compounds was manifested just 12 h after following BBF treatment, this level of phenolic compounds remained higher than control plants during 24 h before decreasing at 48 h.

**Figure 4.** Effect of *F. spiralis* (FSF) and *B. bifurcata* (BBF) fucoidans on the accumulation of phenolic compounds in date palm roots. Means values ± SE. Based on Tukey's test at 12 h and 24 h \* Control vs. BBF: *p* < 0.05, at 24 h, 48 h and 72 h \* Control vs. FSF: *p* < 0.05.
