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The influence of water stress on leaf and stem photosynthesis in Spartium junceum L.
Author(s) -
NILSEN E. T.
Publication year - 1992
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1992.tb00996.x
Subject(s) - photosynthesis , stomatal conductance , horticulture , water stress , transpiration , botany , biology , chemistry
Stem and leaf photosynthetic responses to environmental parameters were studied in Spartium junceum L., a legume with chlorophyllous stems. Stem net photosynthesis (P n ) was consistently lower than leaf P n . The low stem P n was due to lower quantum yield, lower mesophyll conductance and lower CO 2 ‐saturated P n than that of leaf P n . Stomatal limitations to leaf and stem P n were similar (25%). Water stress caused a greater reduction in leaf P n than that of stems. Leaf P n was also reduced in water‐stressed plants following rehydration. The reduced leaf P n was associated with a reduced photon saturated P n rate and a reduced CO 2 saturated P n rate. Apparent quantum yield, mesophyll conductance and stomatal limitation of leaves were unaffected by water‐stress. Stem P n following rehydration was not influenced by the water‐stress treatment. In general, leaf P n was more responsive to environmental parameters and more sensitive to water stress than stem P n . These data support the hypothesis that stem P n has greater tolerance of water stress, but is limited to low P n by biochemical means compared to leaves.