Photosynthesis in newly-developed leaves of heat-tolerant wheat acclimates to long-term nocturnal warming

We examined photosynthetic capacity of newly-developed and pre-existing flag leaves of four wheat genotypes under three night temperatures (15, 20 and 25 °C) and common day temperature of 26 °C in two controlled environment experiments. In newly-developed leaves which acclimated (i.e. maintained or increased) the maximum rate of net CO2 assimilation (An) to long-term (9–13 weeks) nocturnal warming, acclimation was underpinned by greater capacity of Rubisco carboxylation (Vcmax) and photosynthetic electron transport (J). This indicates a night-dependent temperature sensitivity of the activation state of Rubisco. Metabolite profiling linked acclimation of An to greater accumulation of monosaccharides and saturated fatty acids in leaves, suggesting roles for osmotic adjustment of leaf turgor pressure and maintenance of cell membrane integrity. By contrast, warm night-induced inhibition of An was related to reductions in stomatal conductance of CO2 and J, despite higher basal electron trans..., Tcrit: leaf discs were excised during the day from the middle section of detached dark-adapted and were exposed to a temperature ramp at a constant rate of 1°C min−1 from 20 to 65 °C with simultaneous continuous measurement of F0 taken. Tcrit was calculated as the intersection point of two regression lines extrapolated from the flat and steep portion of the F0–temperature response curve. Leaf gas exchange and An-Ci curves: Five LI-COR portable photosynthesis systems (LI-6400XT, LI-COR Inc., Lincoln, NE, USA) were used for gas exchange measurements. The LI-COR units were fitted with 6 cm2 leaf chambers with red-blue light source (6400-18 RGB Light Source, LI-COR). Leaves were exposed to saturating irradiance of 1500 μmol photons m−2 s−1 within the LI-COR leaf chamber, with both the LI-COR leaf chamber/block, and the whole plants were placed within the temperature-controlled cabinet. The LI-COR leaf chamber was initially set to 20°C, reference line atmospheric [CO2] of 400 ppm, a flow rat..., MS Excel and R/R Studio., This README file was generated on 2023-11-02 by Onoriode Coast. GENERAL INFORMATION 1. Title of Dataset: Photosynthesis in newly-developed leaves of heat-tolerant wheat acclimates to long-term nocturnal warming 2. Author Information A. Principal Investigator Contact Information Name: Onoriode Coast Institution: University of New England Address: Armidale, NSW Australia Email: [e-mail] B. Co-investigator Contact Information Name: Andrew P. Scafaro Institution: Australian National University Address: Canberra, ACT Australia Email: [e-mail] C. Co-investigator Contact Information Name: Helen Bramley Address: Hobart, TAS Australia Email: [e-mail] D. Co-investigator Contact Information Name: Nicolas L. Taylor Institution: University of Western Australian Address: Crawley, WA Australia Email: [e-mail] E. Co-investigator Contact Information Name: Owen...本研究在两项可控环境试验中，探究了4个小麦基因型的新展开旗叶与已成熟旗叶的光合能力，试验设置3种夜间温度（15、20、25 ℃）与统一日间温度26 ℃。对于经过9~13周夜间增温驯化的新展开叶片，其净CO₂同化最大速率（An）得以维持或提升，该驯化效应的基础为核酮糖二磷酸羧化酶/加氧酶（Rubisco）羧化能力（Vcmax）与光合电子传递能力（J）的增强。这表明Rubisco的活化状态存在夜间依赖性的温度敏感性。代谢组分析结果显示，An的驯化与叶片中单糖与饱和脂肪酸的积累量提升相关，提示其可能参与叶片膨压的渗透调节以及细胞膜完整性的维持。与之相反，夜间增温诱导的An抑制现象与CO₂气孔导度及J的下降相关，尽管基础电子传递……（原文截断）。 临界温度（Tcrit）测定：于日间从离体暗适应叶片的中部切取叶圆片，以1 ℃·min⁻¹的恒定速率从20 ℃升温至65 ℃，同时持续测量初始荧光（F0）。Tcrit通过从F0-温度响应曲线的平缓段与陡直段分别拟合得到的两条回归直线的交点计算得出。 叶片气体交换与An-Ci曲线测定：采用5台LI-COR便携式光合测定系统（LI-6400XT，美国LI-COR公司，内布拉斯加州林肯市）开展气体交换参数测量。该设备配备6 cm²叶室及红蓝光源（6400-18 RGB光源，LI-COR）。将叶片置于LI-COR叶室中，设置饱和光强为1500 μmol光子·m⁻²·s⁻¹，同时将叶室/叶块与整株植株均放置于控温柜内。初始设置叶室温度为20 ℃，参比气室大气CO₂浓度为400 ppm，气体流量……（原文截断）。本研究数据分析采用MS Excel与R/R Studio软件。本说明文件由Onoriode Coast于2023年11月2日生成。 # 一般信息 1. 数据集标题：耐热小麦新展开旗叶对长期夜间增温的驯化光合特性 2. 作者信息 A. 项目负责人联系方式 姓名：Onoriode Coast 所属机构：新英格兰大学 地址：澳大利亚新南威尔士州阿米代尔 邮箱：[e-mail] B. 合作研究者联系方式 姓名：Andrew P. Scafaro 所属机构：澳大利亚国立大学 地址：澳大利亚首都领地堪培拉 邮箱：[e-mail] C. 合作研究者联系方式 姓名：Helen Bramley 地址：澳大利亚塔斯马尼亚州霍巴特 邮箱：[e-mail] D. 合作研究者联系方式 姓名：Nicolas L. Taylor 所属机构：西澳大利亚大学 地址：澳大利亚西澳大利亚州克劳利 邮箱：[e-mail] E. 合作研究者联系方式 姓名：Owen……（原文未完整提供）