Desert plants secondary metabolites

Plant parts often differ in their levels of secondary metabolites (Table 11.4), some containing extremely high levels. For example, the creosote bush, Larrea tridentata, of the western United States has phenolic resins concentrated in leaves, amounting to as much as 18% of dry weight. In experiments, desert woodrats, Neotoma lepida, selected plant parts of creosote bush with low levels of resins (Meyer and Karazov 1989). 

Chicory (Cichorium intybus) is cultivated in cool regions such as Northern Europe. Recently, this vegetable has arisen out of claims that it is able to promote good health since no pesticides are used to cultivate chicory in the field, while the plant remains noticeably free from herbivore and microbial attack. The bitter substances, lactupicrin, 8-deoxylactucin and some phenolics had previously been shown to possess insect antifeedant properties in chicory (Rees and Harbome, 1985). Specifically, sesquiterpenoid lactones from chicory leaves, such as 8-deoxylactucin and lactupicrin (Figure 1), were identified as insect antifeedants against desert locust, Schistocerca gregaria. Similarly, we found some biologically active secondary metabolites in the... 

---