HAL Id: hal-02821437
https://hal.inrae.fr/hal-02821437
Submitted on 6 Jun 2020
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Methods comparison to assess root mortality in grass species
Catherine Picon-Cochard, Remi Pilon, Sandrine Revaillot, Damien Bardel
To cite this version:
Catherine Picon-Cochard, Remi Pilon, Sandrine Revaillot, Damien Bardel. Methods comparison to assess root mortality in grass species. 7th ISRR Symposium, Root Research and Applications (RootRAP), Sep 2009, Vienne, Austria. 1 p, 2009. �hal-02821437�
Catherine
Catherine Picon-CochardPicon-Cochard, Rémi Pilon, Sandrine Revaillot, Damien Bardel, Rémi Pilon, Sandrine Revaillot, Damien Bardel
INRA, UR874, Grassland Ecosystem Research Team, 234 av du Brézet, 63100 Clermont-Ferrand, France
INRA, UR874, Grassland Ecosystem Research Team, 234 av du Brézet, 63100 Clermont-Ferrand, France picon@clermont.inra.frpicon@clermont.inra.fr
Methods comparison to assess root mortality Methods comparison to assess root mortality
in grass species in grass species
Introduction Introduction
Accurate assessment of root turnover in terrestrial ecosystems is limited by current techniques for estimating root mortality under field conditions.
Accurate assessment of root turnover in terrestrial ecosystems is limited by current techniques for estimating root mortality under field conditions.
Determination of dead roots has been assessed by different time consuming methods: e.g. mass differences, vital colorations, manual and visual Determination of dead roots has been assessed by different time consuming methods: e.g. mass differences, vital colorations, manual and visual assessment, C isotopes, and minirhizotron. In the present study, we compared NIRS spectra with root and soil respiration, vital coloration and assessment, C isotopes, and minirhizotron. In the present study, we compared NIRS spectra with root and soil respiration, vital coloration and minirhizotron.
minirhizotron.
Materials and Methods
Root mortality was induced by removing total aboveground material of five grass species in 50L containers.
Cores of root were collected three times: just after aboveground material (T0), one (T1) and two (T2) months later. Roots were washed, dried, milled and measured with NIRS apparatus from 400 to 2500nm (Foss 6500, USA). Root and soil respiration were measured with a closed chamber (Li600009, Licor, USA), demography of root was measured with a minirhizotron system (Bartztechnology, USA). Vitality of roots was assessed with neutral red after cutting the roots at 110 to 150µm with a manual vibrating microtome (Vibratome®1500).
Results Results
• NIRS: Higher root absorbance spectra for dead treatment were observed in comparison with NIRS: Higher root absorbance spectra for dead treatment were observed in comparison with alive treatment, as previously observed by PiconCochard et al 2009. Differences were more alive treatment, as previously observed by PiconCochard et al 2009. Differences were more pronounced for Ao and Fr.
pronounced for Ao and Fr.
• Minirhizotron: Root mortality of dead treatment reached 10% of total root length that was Minirhizotron: Root mortality of dead treatment reached 10% of total root length that was two times higher than for alive treatment.
two times higher than for alive treatment.
• Vital coloration: Cortex sloughing observed one month after treatment application and two Vital coloration: Cortex sloughing observed one month after treatment application and two months after for the stele, indicated cessation of root functionality and start of root months after for the stele, indicated cessation of root functionality and start of root decomposition.
decomposition.
• Respiration: Sharp declines of soil (SR) and specific root respiration (SRR) for dead treatment Respiration: Sharp declines of soil (SR) and specific root respiration (SRR) for dead treatment after one month of treatment beginning. After two months, very low values of SR and increase of after one month of treatment beginning. After two months, very low values of SR and increase of SRR for 2 species were observed, that could correspond to root decomposition.
SRR for 2 species were observed, that could correspond to root decomposition.
alive
alive dead dead Ao
Dg Fa Lp Fr
0 36 57
alive
alive dead dead
0 36 57 0 36 57 0 36 57
Minirhizotron
Minirhizotron Vital coloration Vital coloration
Days after aerial removal
Soil and root respiration Soil and root respiration
S oil r espiration (S R)
0 10 20 30 40 50 60 70
Ratio Dead / Alive
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
Ao Dg Fa Fr Lp
S pecif ic root respiration (S RR)
Days after aer ial r emoval
0 10 20 30 40 50 60 70
0.0 0.5 1.0 1.5 2.0
36 57
Days after aerial removal
NIRS NIRS
Absorbance (log (1/R)
Wavelength (nm)
Conclusions Conclusions
Histological observations, root and soil respiration and NIRS spectra were more accurate methods to assess root mortality than minirhizotron.
Histological observations, root and soil respiration and NIRS spectra were more accurate methods to assess root mortality than minirhizotron.
NIRS measures changes of chemical composition and possibly cell wall disintegration during root decomposition.
NIRS measures changes of chemical composition and possibly cell wall disintegration during root decomposition.
Perspectives Perspectives
Extend methodology on grassland subjected to extreme event such as summer drought and heatwave.
Extend methodology on grassland subjected to extreme event such as summer drought and heatwave.
