光照与铅锌胁迫对东亚砂藓生理的影响

Effects of Light and Pb-Zn Stress on Physiology and Enrichment of Racomitrium japonicum

摘要: 为了探究光照强度与铅锌胁迫及其交互作用对东亚砂藓生理代谢的影响，对铅锌矿区的生态恢复提供相关数据支撑。以东亚砂藓植株为实验对象，设置不同水平的铅锌胁迫(L₀: 0 + 0 mg∙L⁻¹, L₁: 125 + 100 mg∙L⁻¹, L₂: 250 + 200 mg∙L⁻¹, L₃: 300 + 300 mg∙L⁻¹, L₄: 400 + 400 mg∙L⁻¹)和不同强度的光照处理(全光照处理组I₁₀₀: 100%全光照，中度遮光组I₄₀: 40%全光照，重度遮光组I₁₀: 10%全光照)，测定东亚砂藓叶绿素(Chl)含量、渗透调节物质(可溶性蛋白SP、脯氨酸Pro)、膜系统指标(相对电导率RC、丙二醛MDA)及抗氧化酶活性(过氧化物酶POD、过氧化氢酶CAT、超氧化物歧化酶SOD)。结果显示，叶绿素含量在中度遮光下最高(I₄₀较I₁₀₀提高72.53%)，而铅锌胁迫表现为L₁促进、L₃~L₄抑制叶绿素合成的双重效应，L₄I₁₀₀复合胁迫导致Chla含量降低26.45%。渗透调节物质(SP, Pro)和膜透性(RC)随铅锌浓度增加持续上升，且全光照加剧其积累(L₄I₁₀₀较对照增加3.41倍)。3种抗氧化酶活性均在L₃达峰值，高浓度铅锌胁迫(L₄)显著抑制酶活性。结果说明东亚砂藓通过协同调控叶绿素代谢、渗透调节与抗氧化系统抵御多重胁迫，其在中度遮光下的高耐受性为生态修复提供理论依据‌。

Abstract: In order to explore the effects of light intensity, Pb-Zn stress and their interaction on the physiological metabolism of Racomitrium japonicum, and provide relevant data support for the ecological restoration of Pb-Zn mining areas. The plants of Racomitrium japonicum were collected in the field and exposed to different levels of Pb-Zn stress (L₀: 0 + 0 mg∙L⁻¹, L₁: 125 + 100 mg∙L⁻¹, L₂: 250 + 200 mg∙L⁻¹, L₃: 300 + 300 mg∙L⁻¹, L₄: 400 + 400 mg∙L⁻¹) and different intensities of light (I₁₀₀: full light intensity CK, I₄₀: 40% full sunlight, I₁₀: 10% full sunlight). The chlorophyll content, osmotic adjustment substances (SP, Pro), membrane system indexes (RC, MDA) and antioxidant enzyme activities (POD, CAT, SOD) were measured. Chlorophyll content was the highest under moderate shading (I₄₀ increased by 72.53% compared with I₁₀₀), while Pb-Zn stress showed a dual effect of L₁ promotion and L₃~L₄ inhibition. Compound stress (L₄I₁₀₀) led to a 26.45% decrease in Chla content. The osmoregulatory substances (SP, Pro) and membrane permeability (RC) increased continuously with the increase of Pb-Zn concentration, and the accumulation of them was aggravated by full light (L₄I₁₀₀ increased 3.41 times compared with the control); Antioxidant enzyme activity peaked at L₃ (CAT activity was 4.86 times that of the control), but high concentration stress (L₄) inhibited enzyme activity. Racomitrium japonicum resists multiple stresses through the coordinated regulation of chlorophyll metabolism, osmotic regulation and antioxidant system. Its high tolerance under moderate shading provide a theoretical basis for ecological restoration.