Divergence in physiological responses between cyanobacterial and lichen crusts to a gradient of simulated nitrogen deposition
- Author:
- Zhou X.B., Zhang Y.M. & Yin B.F.
- Year:
- 2016
- Journal:
- Plant and Soil
- Pages:
- 399: 121–134
- Url:
Background and aims: Nitrogen (N) deposition in arid
lands is known to be increasing. However, N deposition
gradients have unclear effects on physiological characteristics
of biocrusts. This study tested if physiological
characteristics are stimulated by low levels of N deposition
and reduced by high levels of N deposition.
Methods We simulated N deposition at various rates to
plots of cyanobacterial and lichen biocrusts in the
Gurbantunggut Desert and measured indicators of
growth and stress.
Results in cyanobacterial crusts, most evidence suggests
that biomass and growth are unaffected by lower
levels of N but suppressed at the highest level. Biomass
and growth of lichen crusts were less sensitive to N
addition but, in the case of actual photochemical efficiency,
were also suppressed at the highest N addition
rate. Most osmotic adjustment substances of
cyanobacterial and lichen crusts did not show significant
responses after N addition. In the two crusts, minor
increase in antioxidative enzyme activity was found in
some N addition rates but no similar trends between the
crust types were observed.
Conclusions Physiological performance of cyanobacterial
crusts was more sensitive to high levels of N addition than
that of lichen crusts. Increasing N deposition might greatly
affect cyanobacterial crusts before lichen crusts.
Keywords Fluorescence . Chlorophyll . Peroxidase .
Catalase . Gurbantunggut desert.
- Id:
- 26130
- Submitter:
- zdenek
- Post_time:
- Monday, 01 February 2016 10:28