Soil Biota and Plant Feedback Flashcards
Plant growth depends on
Pathogens (Nematodes, Fungi): negative effect on growth
Mutualists (Rhizobia, AMF): positive effect on growth
Abiotic factors: temperature, water content, nutrient availability, pH, soil type
Sum of effects: net soil biota effect (may be -, 0 or +)
Soil biota effect
impact of soil organisms on plant growth
Plant-soil feedback (PSF)
„Plant–soil feedback is a process where plants alter the biotic and abiotic qualities of soil they grow in, which then alters the ability of plants to grow in that soil in the future”
previous plant induced changes in soil properties affect subsequent plant growth = legacy effect. Over time a plant species develops a specific composition of soil biota in the rhizosphere = conditioning. each plant species forms ists own soil biota community.
Negative PSF: Plants are less able to grow in soil that was prev. occupied by a member od the same(or a different) species
Positive PSF: Plants are more able to grow…
Legacy effects on abiotic soil conditions & associated soil biota via: litter (leaf and root), Exudates ans uptake processes
Measuring effects of soil biota
Bever´s interaction coefficient
- quantifies how much each plant’s growth is limited by its own soil community compared to how much it limits others (for two-species comparisons)
- Measured by quantifying the growth of two plants, both in soil conditioned by members of their own species, and in soil conditioned by members of the other species
How to study PSFs in plant communities? Experimental approach
-> Two-phase experimental set-ups: Conditioning phase & test phase
-> Always a comparison of plant performance on a “home soil” versus an “away soil”
Treatment approaches for the test phase:
Home and away pairwise/ away mixture
Home: soil from plants rhizosphere (correct soil)
Away: soil from another plants’ rhizosphere (wrong soil)
PSF = 0 no effect
PSF < 0 home soil worse
PSF > 0 home soil better
-> soil legacy effects are inextrictably connected to soil nutruent availability!!
Effect on dominant plant species
Dominant plant species in a plant community show stronger plant-soil feedbakcs
PSF and invasion biology
Invasive species often experience more negative PSF in their native ranges than in their introduced (non-native) ranges.
The longer a species is present the more negatively it is affected by soil biota.
Measuring plant–soil feedback:
- Bever’s interaction coefficient: quantifies how much each plant’s growth is limited by its own soil community compared to how much it limits others (for two-species comparisons)
- Measured by quantifying the growth of two plants, both in soil conditioned by members of their own species, and in soil conditioned by members of the other species
Plant-Plant Interaction
PSFs are suggested to play an important role for:
- plant performance
- plant-plant interactions
- plant community composition
If we have a species rich grassland, the question why these species grow together has not only to do with above ground competition but all soil interactions too.
Allelopathy
- reduces competition
- role inshaping species composition
- occures more often than thought: possibility to develop bioherbicides
Hemiparasites
plants are still having green leaves -> photosynthesis
Holoparasites
no more green leaves, energy gain is completly dependent
Effects of climate change on ecosystems: PSFs matter
-> Quality of litter decreases
Reasons:
1. Elevated nutreint resorption prior to leaf senescence
2. Production of recalcitrant structural compounds
What do you learn from this summary of the field experiment’s results?
Soil legacy effects on responding plant communities are (here) mediated by soil fungi
