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Response of isoprene emission and carbon metabolism to drought in white poplar ( Populus alba ) saplings
Author(s) -
Brilli Federico,
Barta Csengele,
Fortunati Alessio,
Lerdau Manuel,
Loreto Francesco,
Centritto Mauro
Publication year - 2007
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2007.02094.x
Subject(s) - isoprene , photosynthesis , botany , terpenoid , chemistry , metabolism , biology , biochemistry , organic chemistry , copolymer , polymer
Summary• The mechanism uncoupling isoprene emission and photosynthesis under drought was investigated in Populus alba saplings. • Isoprene emission, incorporation of 13 C into the isoprene molecule, isoprene synthase (ISPS) activity, concentration and gene expression, and photosynthesis were measured as a function of the fraction of transpirable soil water (FTSW) and in plants recovering from drought. • Photosynthesis sharply declined below FTSW 30 (a FTSW of 30%) and its inhibition was not caused by metabolic factors. A decline in isoprene emission was only evident towards the FTSW endpoint. 13 C incorporation into isoprene was lower when photosynthesis was constrained by drought. ISPS activity was inhibited by mild drought, while ISPS gene expression and concentration declined in concert with isoprene emission at the FTSW endpoint. Following rewatering, isoprene emission was higher than, and photosynthesis was similar to, prestress values. ISPS activity and concentration, and 13 C incorporation into isoprene, also rapidly recovered to prestress values, while ISPS gene expression remained low in rewatered plants. • Our experiment revealed a larger contribution of alternative carbon sources to isoprene emission only when photosynthesis was dramatically constrained by drought. Isoprene emission was likely controlled at the posttranscriptional level under severe drought.