Leaf Wound Induced Ultraweak Photon Emission Is Suppressed Under Anoxic Stress: Observations Of Spathiphyllum Under Aerobic And Anaerobic Conditions Using Novel In Vivo Methodology

Dataset for paper: ABSTRACT: Plants have evolved a variety of means to energetically sense and respond to abiotic and biotic environmental stress. Two typical photochemical signaling responses involve the emission of volatile organic compounds and light. The emission of certain leaf wound volatiles and light are mutually dependent upon oxygen which is subsequently required for the wound-induced lipoxygenase reactions that trigger the formation of fatty acids and hydroperoxides; ultimately leading to photon emission by chlorophyll molecules. A low noise photomultiplier with sensitivity in the visible spectrum (300 – 720 nm) is used to continuously measure long duration ultraweak photon emission of dark-adapting whole <em>Spathiphyllum</em>leaves (<em>in vivo</em>). Leaves were mechanically wounded after two hours of dark adaptation in aerobic and anaerobic conditions. It was found that (1) nitrogen incubation did not affect the pre-wound basal photocounts; (2) wound induced leaf biophoton emission was significantly suppressed when under anoxic stress; and (3) the aerobic wound induced emission spectra observed was &gt; 650 nm, implicating chlorophyll as the likely emitter. Limitations of the PMT photocathode’s radiant sensitivity, however, prevented accurate analysis from 700 – 720 nm. Further examination of leaf wounding profile photon counts revealed that the pre-wounding basal state (aerobic and anoxic), the anoxic wounding state, and the post-wounding aerobic state statistics all approximate a Poisson distribution. It is additionally observed that aerobic wounding induces two distinct exponential decay events. These observations contribute to the body of plant wound-induced luminescence research and provide a novel methodology to measure this phenomenon <em>in vivo</em>.本数据集配套论文的摘要如下：植物已演化出多种途径，以能量驱动的方式感知并响应非生物与生物环境胁迫。两类典型的光化学信号响应过程涉及挥发性有机化合物（volatile organic compounds）与光子辐射。部分叶片受创伤后释放的挥发性物质与光子辐射二者均依赖氧气；后续的创伤诱导脂氧合酶反应需要氧气参与，该反应可触发脂肪酸与氢过氧化物的生成，最终引发叶绿素分子的光子辐射。本研究采用工作于可见光谱（300~720 nm）的低噪声光电倍增管（photomultiplier），对暗适应的完整白鹤芋（<em>Spathiphyllum</em>）叶片开展长时程连续活体（<em>in vivo</em>）超弱光子辐射测量。实验在有氧与无氧条件下进行，叶片经2小时暗适应后接受机械创伤处理。实验结果显示：(1) 氮气孵育不会影响创伤前的本底光子计数；(2) 无氧胁迫下，创伤诱导的叶片生物光子辐射会被显著抑制；(3) 观测到的有氧创伤诱导辐射光谱波长大于650 nm，表明叶绿素是该辐射的潜在发射源。然而，光电倍增管（PMT）光阴极的辐射灵敏度存在局限，导致无法对700~720 nm波段开展精准分析。对叶片创伤过程的光子计数分布进一步分析后发现，创伤前本底状态（包括有氧与无氧条件）、无氧创伤状态以及创伤后有氧状态的光子计数统计分布均近似于泊松分布（Poisson distribution）。此外，研究还观测到有氧创伤会引发两种截然不同的指数衰减过程。上述研究结果为植物创伤诱导发光领域的研究积累了新的证据，并提供了一种可用于该现象活体测量的全新方法。