Upon illumination, the flow of protons from the stroma into the thylakoid lumen is coupled to the release of Mg2+ from the intra thylakoid space to the stroma. These light actuated ion fluxes decrease the stromal concentration of protons (the pH increases from 7 to 8) and increase that of Mg2+ by 2 to 5 mM. 

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#Id: 9743

#Unit 6. System Physiology – Plant

Glycosylated triterpenoid compound avenacin A1, found in oat (Avena sativa) roots The wheat root pathogen Gaeumannomyces graminis var. tritici is extremely sensitive to avenacins

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#Id: 9744

#Unit 6. System Physiology – Plant

Tomato plants produce tomatine, a compound that is closely related to avenacin. Only certain pathovars of the fungal pathogen Septoria lycopersici can cause disease on tomatoes, and these pathovars produce a glucosidase that can detoxify tomatine.

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#Id: 9745

#Unit 6. System Physiology – Plant

According to Optimal Defense Hypothesis, 

Young tissues not only contain the highest levels of constitutive secondary compounds, they are also more responsive to herbivory. Thus, younger leaves exhibit more robust inducible defenses to herbivores than older leaves.

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#Id: 9746

#Unit 6. System Physiology – Plant

Constitutive defenses are costly to the plant. The production of secondary metabolites requires a significant energy investment derived from primary metabolism, which is then unavailable for use in growth and reproduction.

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#Id: 9747

#Unit 6. System Physiology – Plant

Inducible defense against pests or pathogens, involve both a wound response and the recognition of certain compounds abundant in the insect’s saliva or regurgitant. 

These compounds belong to a broad group of chemicals called elicitors

TLS Online TPP Program

#Id: 9748

#Unit 6. System Physiology – Plant

Elicitors are HAMPs or herbivore- associated molecular patterns