Effect of vapor pressure deficit on gas exchange in wild-type and abscisic acid-insensitive plants

编号 040021305

推送时间 20191118

研究领域 森林培育 

年份 2019 

类型 期刊 

语种 英语

标题 Effect of vapor pressure deficit on gas exchange in wild-type and abscisic acid-insensitive plants

来源期刊 BMC Plant Biology

期 第213期

发表时间 20190927

关键词 ABA-signaling;  Drought stress;  HOS15;  OST1;  ABI1/2;  Protein degradation and stability; 

摘要 Stomata control the gas exchange of terrestrial plant leaves, and are therefore essential to plant growth and survival. We investigated gas exchange responses to vapor pressure deficit (VPD) in two grey poplar (Populus × canescens) lines: wild type (WT), and abscisic acid-insensitive (abi1) with functionally impaired stomata. Transpiration rate in abi1 increased linearly with VPD, up to about 2 kPa. Above this, sharply declining transpiration was followed by leaf death. In contrast, WT showed a steady or slightly declining transpiration rate up to VPD of nearly 7 kPa, and fully recovered photosynthetic function afterward. There were marked differences in discrimination against 13CO2 (Δ13C) and C18OO (Δ18O) between abi1 and WT plants. The Δ13C indicated that intercellular CO2 concentrations decreased with VPD in WT plants, but not in abi1 plants. The Δ18O reflected progressive stomatal closure in WT in response to increasing VPD; however, in abi1, stomata remained open and oxygen atoms of CO2 continued to exchange with 18O enriched leaf water. Coupled measurements of Δ18O and gas exchange were used to estimate intercellular vapor pressure, ei. In WT leaves, there was no evidence of unsaturation of ei, even at VPD above 6 kPa. In abi1 leaves, ei approached 0.6 times saturation vapor pressure before the precipitous decline in transpiration rate. For WT, a sensitive stomatal response to increasing VPD was pivotal in preventing unsaturation of ei. In abi1, after taking unsaturation into account, stomatal conductance increased with increasing VPD, consistent with a disabled active response of guard cell osmotic pressure.

服务人员 孙小满

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