Fig. 4 in The complexity of sound quantification of specialized metabolite biosynthesis: The stress related impact on the alkaloid content of Catharanthus roseus

Fig. 4. The stress-related increase of the concentration of natural products. In principle, two major effects are responsible for the stress-related increase, i. e., the decrease of the reference value (e.g. dry weight), and an enhancement of biosynthetic activity. The latter one is due either to stress-related up-regulation ("active increase" of enzymatic activity) or a "passive shift" cause by the stress-related overreduction due to stomatal closure. Decreases of factors are displayed in red, the related enhancements in blue. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)