Response of isoprene emission and carbon metabolism to drought in white poplar (Populus alba) saplings
Response of isoprene emission and carbon metabolism to drought in white poplar (Populus alba) saplings
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DOI：
10.1111/j.1469-8137.2007.02094.x
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发表时间：
2007-01-01
期刊：
影响因子：
9.4
通讯作者：
Centritto, Mauro
中科院分区：
文献类型：
--
作者：
Brilli, Federico;Barta, Csengele;Centritto, Mauro
研究了干旱条件下白杨幼树异戊二烯释放和光合作用解偶联的机理，测定了异戊二烯释放、异戊二烯分子中C-13的掺入、异戊二烯合成酶(ISPS)活性、浓度、基因表达和光合作用随土壤水分透性(FTSW)的变化，以及植物在干旱条件下的光合作用。异戊二烯排放量的下降只在接近FTSW终点时才明显。当光合作用受到干旱抑制时，C-13掺入异戊二烯的量较低。ISPS活性受到轻度干旱的抑制，而ISPS基因的表达和浓度随着FTSW终点的异戊二烯排放而下降。复水后，异戊二烯释放量高于预应激值，而光合作用与预应激值相近。在复水植株中，ISPs的活性和浓度以及C-13并入异戊二烯也迅速恢复到预应激值，而ISPS基因的表达仍然很低。我们的实验表明，只有当光合作用受到干旱的严重限制时，替代碳源对异戊二烯排放的贡献才更大。在严重干旱条件下，异戊二烯的排放可能被控制在转录后水平。
The mechanism uncoupling isoprene emission and photosynthesis under drought was investigated in Populus alba saplings.Isoprene emission, incorporation of C-13 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 FTSW30 (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. C-13 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 C-13 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.