Premium
Biomass and leaf‐level gas exchange characteristics of three African savanna C 4 grass species under optimum growth conditions
Author(s) -
Mantlana K. B.,
Veenendaal E. M.,
Arneth A.,
Grispen V.,
Bonyongo C. M.,
Heitkonig I. G.,
Lloyd J.
Publication year - 2009
Publication title -
african journal of ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.499
H-Index - 54
eISSN - 1365-2028
pISSN - 0141-6707
DOI - 10.1111/j.1365-2028.2008.00961.x
Subject(s) - biomass (ecology) , water use efficiency , photosynthesis , panicum , agronomy , stomatal conductance , digitaria , biomass partitioning , repens , biology , botany , environmental science
C 4 savanna grass species, Digitaria eriantha , Eragrostis lehmanniana and Panicum repens , were grown under optimum growth conditions with the aim of characterizing their above‐ and below‐ground biomass allocation and the response of their gas exchange to changes in light intensity, CO 2 concentration and leaf‐to‐air vapour pressure deficit gradient ( D l ). Digitaria eriantha showed the largest above‐ and below‐ground biomass, high efficiency in carbon gain under light‐limiting conditions, high water use efficiency (WUE) and strong stomatal sensitivity to D l ( P = 0.002; r 2 = 0.5). Panicum repens had a high aboveground biomass and attained high light saturated photosynthetic rates ( A sat , 47 μmol m −2 s −1 ), stomatal conductance, ( g sat , 0.25 mol m −2 s −1 ) at relatively high WUE. Eragrostis lehmanniana had almost half the biomass of other species, and had similar A sat and g sat but were attained at lower WUE than the other species. This species also showed the weakest stomatal response to D l ( P = 0.19, r 2 = 0. 1). The potential ecological significance of the contrasting patterns of biomass allocation and variations in gas exchange parameters among the species are discussed.