Plant-induced differentiation of soil variables and nematode community structure in a Mediterranean serpentine ecosystem

Soil Research ◽  
2014 ◽  
Vol 52 (6) ◽  
pp. 593 ◽  
Author(s):  
Nikolaos Monokrousos ◽  
George Charalampidis ◽  
George Boutsis ◽  
Varvara Sousanidou ◽  
Efimia M. Papatheodorou ◽  
...  

Abiotic and biotic components of a serpentine Mediterranean soil were studied in terms of heavy metal and nutrient concentrations, microbial biomass, and structural and functional characteristics of the soil nematode community. We explored differentiations of the soil environment imposed by vegetation, sampling the bare soil and soil under Buxus sempervirens, Juniperus oxycedrus, Cistus creticus and Thymus sibthorpii. Organic matter, microbial biomass, nutrient availability and calcium/magnesium (Ca/Mg) ratio of the serpentine site were similar to those of degraded, non-serpentine Mediterranean ecosystems; the serpentine site showed potassium deficiency and high heavy metal load. Soil nematode abundance, especially of phytoparasites, was very low. Low enrichment and structure indices and high channel index values indicated a degraded, low-resource, stressful environment where fungal decomposition predominates. There was no differentiation of heavy metal concentrations among microsites. Bare soil exhibited high pH, low water content, low Ca/Mg (0.68), low nutrient concentrations, low abundance of most nematode groups, low values of maturity and plant parasitic indices, low nematode diversity and a distinct generic composition. Rhizosphere soil was differentiated according to the evergreen–sclerophyllous or seasonal–dimorphic habit of shrubs. This was reflected in soil nutrients and in all parameters of the soil nematode community.

Soil Research ◽  
2016 ◽  
Vol 54 (8) ◽  
pp. 905
Author(s):  
Nikolaos Monokrousos ◽  
George Charalampidis ◽  
Pantelitsa Kapagianni ◽  
Maria D. Argyropoulou ◽  
Efimia M. Papatheodorou

We investigated the variations in space and time of soil functionality in a Mediterranean serpentine soil for heavy metal and nutrient concentrations, microbial biomass and soil enzymatic activities (urease, dehydrogenase and alkaline phosphatase) in the rhizospheres of different plant species and in bare soil, during the humid and dry seasons of the year. Nutrients and heavy metals were also estimated in leaves of shrubs inhabiting the study area. Four species of serpentine-tolerant shrubs were present: the evergreen-sclerophyllous Juniperus oxycedrus and Buxus sempervirens and the phryganic Cistus creticus and Thymus sibthorpii. The most significant differentiation of the soil environment was between bare and rhizosphere soil, and was mainly driven by the availability of potassium. Spatial variations related to plant identity were clear but less important than temporal variations. There was no relationship between soil and foliar concentrations of nutrients and heavy metals. Higher foliar concentrations were recorded in the phryganic species. Finally, there was no enzyme inhibition due to the heavy metal load of the serpentine soil. Enzymatic activities were lower for bare soil samples, while their temporal variations probably followed the temporal variations of temperature and humidity imposed by the Mediterranean climate.


Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 326
Author(s):  
Nikolaos Monokrousos ◽  
Maria D. Argyropoulou ◽  
Kalliopi Tzani ◽  
Urania Menkissoglou-Spiroudi ◽  
George Boutsis ◽  
...  

We investigated the effects of three botanicals with nematicidal properties (anise-Pimpinella anisum, parsley-Petroselinum crispum, and rocket-Eruca sativa) on the soil nematode community, in terms of trophic structure and nematode genera composition. We compared effects with those of fluopyram (synthetic nematicide) and Nemagold (bionematicide). We assessed the role of time, by sampling 15 and 45 days after treatments and analyzing nematode genera and microbial phospholipid fatty acid biomarkers (PLFA). Soil incorporation of botanicals reduced plant parasitic nematodes, increased bacterivores, especially the enrichment opportunists and among them Rhabditis, having no effect on fungivores and non-parasitic plant feeders. Neither the number nor the composition and dominance hierarchy of nematode genera were affected. Nemagold did not induce any significant change, while fluopyram decreased both free-living and parasitic nematodes, but with no uniform effect against all genera. The least affected genus was the fungivorous Aphelenchus. While most microbial PLFAs increased with time, the abundances of nematode genera did not change, except the Meloidogyne incognita second stage juveniles, which emerged in soil only 45 days after treatments. The low enrichment index and high channel index values of the fluopyram soil samples indicated a stressful environment. The opposite was observed in the botanical treatments, especially parsley and rocket.


BMC Ecology ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Xiaodan Liu ◽  
Dengxiao Zhang ◽  
Huixin Li ◽  
Xiuxiu Qi ◽  
Ya Gao ◽  
...  

PLoS ONE ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. e0230153 ◽  
Author(s):  
Gisèle L. Herren ◽  
Joos Habraken ◽  
Lieven Waeyenberge ◽  
Annelies Haegeman ◽  
Nicole Viaene ◽  
...  

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