Do lichens have "memory" of their native nitrogen environment?

Area of Science:

• Environmental Science
• Plant Physiology
• Ecology

Background:

• Lichens are sensitive bioindicators of environmental conditions.
• Wet nitrogen deposition poses a significant threat to lichen health and survival.
• Intraspecific adaptations in lichens to nitrogen pollution are not fully understood.

Purpose of the Study:

• To investigate the physiological mechanisms of nitrogen tolerance in Xanthoria parietina.
• To determine how native nitrogen availability influences lichen response to ammonium sulfate exposure.
• To assess the impact of varying nitrogen deposition levels on lichen physiology.

Main Methods:

• Xanthoria parietina thalli were collected from areas with high and low nitrogen deposition.
• Lichens were exposed to different concentrations of ammonium sulfate ((NH₄)₂SO₄) solutions.
• Physiological parameters measured included maximal PSII efficiency, ion localization (K+, Mg²+), and buffer capacity.

Main Results:

• Significant physiological differences were observed between lichens from high and low nitrogen environments.
• Lichens previously exposed to higher nitrogen levels exhibited better coping mechanisms.
• Native nitrogen environment significantly marked the physiological responses of X. parietina.

Conclusions:

• Xanthoria parietina demonstrates adaptive capacity to nitrogen pollution.
• Pre-existing nitrogen availability in the native environment is crucial for enhancing tolerance.
• Understanding these intraspecific mechanisms is vital for lichen conservation amidst rising nitrogen deposition.