College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong, Shanxi, 030600, China; Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Chemosphere. 2023 Apr;319:138019. doi: 10.1016/j.chemosphere.2023.138019. Epub 2023 Jan 31.
The influence of environmental factors on Cd accumulation by Hylotelephium spectabile and its physiological mechanisms are unclear. A field trial was conducted to investigate the effects of nitrogen, soil moisture, and light regulation on plant growth, Cd absorption and translocation, and the photosynthetic characteristics of two H. spectabile populations (LN with high Cd accumulation capacity and HB1 with relatively low Cd accumulation capacity). The results showed that Cd accumulation in LN was 59.6% higher than that in HB1 which may partly be explained by the inherent high transpiration rate of LN, especially at the terminal stage. In addition, the photosynthetic rate of LN responded more positively to nitrogen than HB1, which further amplified its advantages on plant growth and Cd accumulation. Moderate drought significantly stimulated root growth of LN, indicating that LN possesses stronger resistance to drought. Shade inhibited Cd distribution, rather than directly affecting Cd concentrations in H. spectabile. The combined stress of shade and drought had a synergistic effect on Cd translocation in H. spectabile. Moreover, LN achieved 17.3%∼444.5% higher transpiration levels than HB1 under environmental stress, which ensured a more efficient Cd transport capacity of LN. Therefore, the investigation of photosynthetic characteristics further revealed the physiological mechanism by which LN accumulated Cd superior to HB1 under environmental stress and responded more positively to nitrogen nutrition.
环境因素对八宝景天 Cd 积累的影响及其生理机制尚不清楚。本试验通过大田试验，研究氮、土壤水分和光照调控对 2 种八宝景天种群（高 Cd 积累能力的 LN 和相对低 Cd 积累能力的 HB1）生长、Cd 吸收和转运以及光合特性的影响。结果表明，LN 中 Cd 的积累量比 HB1 高 59.6%，这可能部分归因于 LN 固有的高蒸腾速率，尤其是在末期。此外，LN 对氮的光合响应比 HB1 更为积极，这进一步放大了其在植物生长和 Cd 积累方面的优势。适度干旱显著促进了 LN 的根系生长，表明 LN 具有更强的抗旱性。遮荫抑制了 Cd 的分布，而不是直接影响八宝景天体内的 Cd 浓度。遮荫和干旱的联合胁迫对八宝景天体内 Cd 的转运具有协同作用。此外，在环境胁迫下，LN 的蒸腾水平比 HB1 高 17.3%~444.5%，这确保了 LN 具有更高效的 Cd 转运能力。因此，对光合特性的研究进一步揭示了在环境胁迫下 LN 积累 Cd 优于 HB1 且对氮素营养响应更为积极的生理机制。
