Multivariate analysis of the response of cotton lavender (Santolina chamaecyparissus) to lead stress

Abstract

Cotton lavender is a shrubby aromatic plant with several uses in medical and pesticide issues. The objective of the present work was to determine the physiological response of cotton lavender plants (Santolina chamaecyparissus) against lead stress through chemometric tools assessing tolerance for Pb stress. Seedlings were arranged in pots of 1 kg with sand:vermiculite (3:1) as substrate and grown in a greenhouse. Macro and micronutrients were applied with 1 g of Nitrofull fertilizer every 30 days until the end of the experiment. 32 days after the experiment started (AES), plants were watered with PbCl2 solution until they reached concentrations in substrate 0, 250, 500, 1000, and 2000 ppm of Pb. 25 weeks AES, plant growth parameter was measured with image analysis software. At week 27 AES, samples were collected to determine lipid peroxidation (LP), catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (GOPX) activity. The data were analyzed by uni and multivariates statistics. Score plot defined two groups in which concentrations up to 1000 ppm of Pb performed one group, and the other grouped 2000 ppm Pb treatment. The loading plot indicated that such difference is due to the influence of LP, CAT, APX, and GOPX, which they increase at 2000 ppm Pb in accordance with univariate statistics. Results indicate that treatments up to 1000 ppm Pb have a slightly-moderate physiological response with respect to the 0 ppm Pb, while at 2000 ppm biomass production is inhibited, and lipid peroxidation and antioxidant enzyme activity increase significantly. In conclusion, the results indicate that cotton lavender has high tolerance in conditions up to 1000 ppm of Pb, presenting effects and responses to oxidative stress at 2000 ppm Pb. Thus, this specie could be potentially useful as a phytoremediator in contaminated areas with Pb.