Foliar pH as a new plant trait: can it explain variation in foliar chemistry and carbon cycling processes among subartic plant species and types?

CORNELISSEN, J.H.C.; QUESTED, H.M.; VAN LOGTESTIJN, R.S.P.; PÉREZ-HARGUINDEGUY, N.; GWYN-JONES, D.; DÍAZ, S.; GALLAGHAN, T.V.; PRESS, M.C.; AERTS, R.

OECOLOGIA

Springer

Año: 2006 vol. 147 p. 315 - 326

0029-8549

Plant traits have become popular as predictors  of interspecific variation in important ecosystem properties  and processes. Here we introduce foliar pH as a  possible new plant trait, and tested whether (1) green  leaf pH or leaf litter pH correlates with biochemical and  structural foliar traits that are linked to biogeochemical  cycling; (2) there is consistent variation in green leaf pH  or leaf litter pH among plant types as defined by nutrient  uptake mode and higher taxonomy; (3) green leaf pH  can predict a significant proportion of variation in leaf  digestibility among plant species and types; (4) leaf litter  pH can predict a significant proportion of variation in  leaf litter decomposability among plant species and  types. We found some evidence in support of all four  hypotheses for a wide range of species in a subarctic  flora, although cryptogams (fern allies and a moss)  tended to weaken the patterns by showing relatively  poor leaf digestibility or litter decomposability at a given  pH. Among seed plant species, green leaf pH itself explained  only up to a third of the interspecific variation in  leaf digestibility and leaf litter up to a quarter of the  interspecific variation in leaf litter decomposability.  However, foliar pH substantially improved the power of  foliar lignin and/or cellulose concentrations as predictors  of these processes when added to regression models  as a second variable. When species were aggregated into  plant types as defined by higher taxonomy and nutrient  uptake mode, green-specific leaf area was a more powerful  predictor of digestibility or decomposability than  any of the biochemical traits including pH. The usefulness  of foliar pH as a new predictive trait, whether or  not in combination with other traits, remains to be tested  across more plant species, types and biomes, and  also in relation to other plant or ecosystem traits and  processes.