Crescimento e perfil bioquímico por espectroscopia no infravermelho de plântulas de mimosa tenuiflora com diversas intensidades do campo magnético

Abstract

The presence of a magnetic field (MF) can affect the biological conditions of plants. At certain intensity levels, it can cause damage to plant germination and growth. In this study, middle infrared (MIR) spectroscopy was used together with statistical treatments to identify changes in growth and biochemical profile in Mimosa tenuiflora (Willd.) Poir., seedlings exposed to magnetic fields at different intensities under controlled environments. The study was carried out at the Laboratory of Energy, Physics and Mathematics together with the Chemical Analysis Group at the Academic Unit of Serra Talhada. The species analyzed was chosen because it is native to the Caatinga. Spectral data were compared with biometric and physiological data, such as germination percentage (G), radicle length (RL), hypocotyl length (HL) and leaf morphometry (LM). M. tenuiflora seeds were placed in Petri dishes with qualitative filters and allocated in a BOD (Biochemical Oxygen Demand) incubator under controlled temperature (250C) and photoperiod (12h), and divided into two groups: closer to the light source (group C) and distant (group D). Samples of the seedlings (leaves, hypocotyl, and radicle) were subjected to MID spectroscopic analysis by attenuated total reflectance (ATR). RL, HL, and LM values decreased significantly (p<0.05) in the group closer to the light source compared to the control. Principal component analysis (PCA) of the spectral data of the samples allowed to see a significant distinction between the samples from group C and group D. Considering the analysis of samples that received an intensity of 0.24T for group C and 0.18T for group D, differences were noted in the range of 1200 to 1000cm−1 corresponding to C-O, C-H, and OH vibrations and in the range of 1050 and 1735cm−1 associated with C=O stretching bands, respectively. Together, the data suggest that MF acts differently on seedlings depending on the distance from the light source. Through MIR spectra it was possible to evaluate the composition and intensity of the bands and, when associated with statistical treatments (Student’s t-test and PCA), proved to be a promising and complementary tool for studying the effect of magnetic fields on plants in relation to the light source.