Kawaguchi Toshiro, Mukae Katsuya, Takahashi Yoshihiro, Ichiki Hirofumi
Kyushu Sangyo University, 2-3-1, Matsukadai, Higashi-Ku, Fukuoka, 813-8503, Japan.
Faculty of Life Science, Kyushu Sangyo University, Fukuoka, 813-8503, Japan.
BMC Plant Biol. 2025 Aug 1;25(1):1007. doi: 10.1186/s12870-025-07029-0.
Plants emit into the air trace amounts of cations (e.g., K and NH) and anions (e.g., NO and PO) that are involved in their physiological processes. Background ion charges in the air mask very low concentrations of plant-emitted ions in the air. Conventional air ion counters cannot measure these concentrations. Therefore, we devised a single magnetically levitated electrode ionization chamber (MALIC) unit system incorporating 3 MALIC units-a novel measuring system that is noninjurious to plants by being noncontact and pulsed electronic field-free and allows for the real-time monitoring of very low net concentrations (10 to 10 ions/mL) of plant-emitted ions in the air by subtracting background ion charges from cation and anion concentrations. The present study aimed to assess the performance of the system to measure these ion charges and ion and net ion concentrations.
Concentrations of ions, which had been emitted into the air by two Crassulacean Acid Metabolism plants [Crassula ovata (1 strain; 390 leaves) and Schlumbergera truncata (4 strains; 110 stem nodes per strain)] cultivated under almost the same cultivation conditions (light source, light intensity, light/dark state, flowering/flowerless stage, temperature, and humidity), were measured. Consequently, the system precisely measured very low background ion charge-subtracted, net, and average net concentrations of the relevant concentrations and separately collected cation and anion aggregates. Changes in net and average net ion concentrations in Crassula ovata that were exposed to three light sources (silica light, white fluorescent light, and fluorescent light for plant growth) and in Schlumbergera truncata in the light (white fluorescent light)/dark states and at the flowering/flowerless stages were congruent with their photosynthetic profiles, thus providing indirect evidence for the physiological traits of CAM plants.
The performance of a single MALIC unit system to precisely measure very low net ion concentrations in the air was demonstrated successfully, thus meeting its objective. The system monitors the concentrations in a real-time manner and separately collects the aggregates of cations and anions emitted from leaves, stem nodes, and flowers, thus directly providing ion aggregate materials as a novel measurement tool for ion homeostasis research without causing any damage to plants.
植物会向空气中释放痕量阳离子（如钾离子和铵根离子）和阴离子（如硝酸根离子和磷酸根离子），这些离子参与其生理过程。空气中的背景离子电荷掩盖了植物释放到空气中的极低浓度的离子。传统的空气离子计数器无法测量这些浓度。因此，我们设计了一种包含3个磁悬浮电极电离室（MALIC）单元的单磁悬浮电极电离室单元系统——一种新型测量系统，该系统通过非接触且无脉冲电场对植物无害，并通过从阳离子和阴离子浓度中减去背景离子电荷来实时监测空气中植物释放的极低净浓度（10至10个离子/毫升）的离子。本研究旨在评估该系统测量这些离子电荷以及离子和净离子浓度的性能。
测量了在几乎相同的栽培条件（光源、光照强度、光/暗状态、开花/无花阶段、温度和湿度）下培养的两种景天酸代谢植物[玉树（1株；390片叶子）和蟹爪兰（4株；每株110个茎节）]释放到空气中的离子浓度。结果，该系统精确测量了极低的经背景离子电荷扣除后的相关浓度的净浓度和平均净浓度，并分别收集了阳离子和阴离子聚集体。暴露于三种光源（石英灯、白色荧光灯和植物生长用荧光灯）下的玉树以及处于光照（白色荧光灯）/黑暗状态和开花/无花阶段的蟹爪兰的净离子浓度和平均净离子浓度变化与其光合特征一致，从而为景天酸代谢植物的生理特性提供了间接证据。
成功证明了单MALIC单元系统精确测量空气中极低净离子浓度的性能，从而实现了其目标。该系统以实时方式监测浓度，并分别收集从叶片、茎节和花朵中释放的阳离子和阴离子聚集体，从而直接提供离子聚集体材料，作为离子稳态研究的新型测量工具，且不会对植物造成任何损害。
