基于主成分分析法的枫香耐铅性及土壤修复潜力研究

探究枫香(Liquidambar formosana Hance)对铅污染土壤的修复作用,为缓解土壤铅危害和枫香在重金属污染地推广种植提供科学参考,以1年生枫香幼苗为试材,设置6个Pb~(2+)浓度(分别为0,100,300,500,800,1 000 mg/kg)对各Pb~(2+)浓度环境下枫香幼苗的生理特性和积累特性进行研究,并采用主成分分析法对枫香的12个生理指标进行筛选以及耐性评价。结果表明,随着Pb~(2+)的增加,枫香幼苗叶片的生物量、可溶性糖含量、可溶性蛋白含量、游离脯氨酸含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)均呈上升—下降趋势,表现出"低促高抑";丙二醛(MAD)含量则呈上升趋势;叶绿素a和叶绿素b均呈下降趋势,但是叶绿素a的下降趋势不显著;净光合速率(P_n)、气孔导度(G_s)、CO_2浓度(C_i)和蒸腾速率(T_r)均呈上升—下降趋势。枫香地下部分的铅含量地上部分的铅含量,转移系数在T2、T3时较大,富集系数与胁迫浓度呈负相关。主成分分析结果表明,提取的2个主成分积累贡献率高达92.462%,说明这2个主成分可以反映大部分信息,游离脯氨酸、净光合速率、气孔导度、胞间CO_2浓度、蒸腾速率和SOD活性为简化后的6个指标。由主成分得分得出,枫香幼苗耐铅性高低排序为T3T4T2T1T5T6。综合表明,枫香幼苗对重金属铅具有一定的耐受能力、富集和转移能力,可为重金属污染较重的地区引种枫香和缓解土壤重金属污染作一定的理论依据。

Lead Tolerance and Soil Remediation Potential of Liquidambar formosana Hance-Based on Principal Component Analysis

To explore the remediation of Liquidambar formosana Hance to lead-contaminated soil and provide scientific reference for the promotion of planting maple in contaminated heavy metals, annual L. formosana Hance seedlings were used as test materials, the physiological characteristics and accumulation characteristics of L. formosana Hance seedlings under 6 Pb²⁺ concentrations (0, 100, 300, 500, 800, and 1 000 mg/kg) were studied. The principal component analysis method was used to screen the 12 physiological indexes of L. formosana Hance and evaluate the tolerance. The results showed that with the increase of Pb²⁺ concentration, the biomass, soluble sugar content, soluble protein content, free proline content, superoxide dismutase (SOD), and peroxidase (POD) of L. formosana seedling leaves showed a upward-downward trend, which indicate a "low promotes high suppression" effect. The content of malondialdehyde (MAD) showed an upward trend. Both chlorophyll a and chlorophyll b showed a downward trend, but the downward trend of chlorophyll a was not significant. Net photosynthetic rate (P_n), stomatal conductance (G_s), CO₂ concentration (C_i), and transpiration rate (T_r) all showed an upward-downward trend. The lead content in the underground part of L. formosana>the lead content in the above-ground part, the transfer coefficient was the largest at T2 and T3, and the enrichment coefficient was negatively correlated with the stress concentration. The results of principal component analysis showed that the cumulative contribution rate of the two principal components extracted was as high as 92.462%, indicating that these two principal components can reflect most of the information. Free proline, net photosynthetic rate, stoma conductance, intercellular CO₂ concentration, transpiration speed, and SOD activity were the simplified 6 indexes. The principal component scores showed that the lead tolerance of L. formosana seedlings is ranked as T3>T4>T2>T1>T5>T6. Comprehensively, the L. formosana Hance seedlings have certain tolerance, enrichment, and transfer ability to heavy metal lead, and this study provide theoretical basis for introducing L. formosana Hance to areas with heavy metal pollution and alleviating soil heavy metal pollution.