high quantities, usually with negative effects in biomass production or morphology,
but increasing plant quality in terms of aroma, taste or color. The metabolic profile
and general response of elicitation vary greatly depending on the plant model, the
elicitor level or concentration, and the stimulation time. Considering these facts,
this chapter clearly and concisely discusses the most current strategies of elicitation
for the increase of secondary metabolites production in plants.
Keywords Secondary metabolites Á Eustress Á Distress Á Defense in plant Á
Elicitation
5.1 Introduction
A variety of substances or compounds called secondary metabolites are mainly
responsible for the adaptation of plants to environmental changes. Plants synthesize
a wide range of secondary metabolites such as alkaloids, flavonoids, phenolic,
steroids, anthocyanins between others, which are used as pharmaceuticals, agrochemicals, biopesticides, color, additives, etc. Secondary metabolites are not considered to be part of fundamental life processes of plants, however, they play a
significant role in protection from insect, pest, herbivores, phytopathogens, and
other harsh environmental variables (Thakur et al. 2019). Therefore, the synthesis
of secondary metabolites depends on internal and external factors (stressors and
stress factors, respectively) that influence plant metabolism, and can affect plant
reproduction and productivity (Kranner et al. 2010). The stress factors, that for their
nature can be biotic or abiotic, modify positively or negatively the plant metabolism (Cheynier et al. 2013). Biotic stress is the result of the interaction between
plant and viral, bacterial, fungi, pheromones, phytohormones, and nucleic acids
among others. Meanwhile, abiotic stress can be physical factors (Light spectra,
temperature, water stress, acoustic waves, others) and chemical factors
(Nanostructures, gasses, nutriment, others) (Vázquez-Hernández et al. 2019).
According to data provided by Agathokleous et al. (2019), exist 109,821 publications that review the topic of “plant stress” only in the period 2000 to 2018. The
results indicated that the dose–response is not always linear, observing a biphasic
response when the doses allow it. This balance of response between the plant and
stress factors provides information on a positive (eustress) or a negative effect
(distress), a phenomenon called “Hormesis” (Agathokleous et al. 2019;
Vázquez-Hernández et al. 2019). The concept of hormesis is a term used in medicine for the application of toxins in low doses (Calabrese 2004). Paracelsus (1493–
1541) defined it as “All things are poison and nothing is without poison, only the
dose permits something not to be poisonous” (cited by (Vázquez-Hernández et al.
2019)). Currently, the term is applied in horticultural and agricultural practices as a
biphasic response in which doses of a toxic agent could cause inhibition (distress)
or can cause stimulation (eustress) (Vargas-Hernandez et al. 2017).
152
H. Aguirre-Becerra et al.
but increasing plant quality in terms of aroma, taste or color. The metabolic profile
and general response of elicitation vary greatly depending on the plant model, the
elicitor level or concentration, and the stimulation time. Considering these facts,
this chapter clearly and concisely discusses the most current strategies of elicitation
for the increase of secondary metabolites production in plants.
Keywords Secondary metabolites Á Eustress Á Distress Á Defense in plant Á
Elicitation
5.1 Introduction
A variety of substances or compounds called secondary metabolites are mainly
responsible for the adaptation of plants to environmental changes. Plants synthesize
a wide range of secondary metabolites such as alkaloids, flavonoids, phenolic,
steroids, anthocyanins between others, which are used as pharmaceuticals, agrochemicals, biopesticides, color, additives, etc. Secondary metabolites are not considered to be part of fundamental life processes of plants, however, they play a
significant role in protection from insect, pest, herbivores, phytopathogens, and
other harsh environmental variables (Thakur et al. 2019). Therefore, the synthesis
of secondary metabolites depends on internal and external factors (stressors and
stress factors, respectively) that influence plant metabolism, and can affect plant
reproduction and productivity (Kranner et al. 2010). The stress factors, that for their
nature can be biotic or abiotic, modify positively or negatively the plant metabolism (Cheynier et al. 2013). Biotic stress is the result of the interaction between
plant and viral, bacterial, fungi, pheromones, phytohormones, and nucleic acids
among others. Meanwhile, abiotic stress can be physical factors (Light spectra,
temperature, water stress, acoustic waves, others) and chemical factors
(Nanostructures, gasses, nutriment, others) (Vázquez-Hernández et al. 2019).
According to data provided by Agathokleous et al. (2019), exist 109,821 publications that review the topic of “plant stress” only in the period 2000 to 2018. The
results indicated that the dose–response is not always linear, observing a biphasic
response when the doses allow it. This balance of response between the plant and
stress factors provides information on a positive (eustress) or a negative effect
(distress), a phenomenon called “Hormesis” (Agathokleous et al. 2019;
Vázquez-Hernández et al. 2019). The concept of hormesis is a term used in medicine for the application of toxins in low doses (Calabrese 2004). Paracelsus (1493–
1541) defined it as “All things are poison and nothing is without poison, only the
dose permits something not to be poisonous” (cited by (Vázquez-Hernández et al.
2019)). Currently, the term is applied in horticultural and agricultural practices as a
biphasic response in which doses of a toxic agent could cause inhibition (distress)
or can cause stimulation (eustress) (Vargas-Hernandez et al. 2017).
152
H. Aguirre-Becerra et al.