Physiological response of sorghum seeds treated with Arsenicum album submitted to low temperature

Abstract

Introduction: Temperature is one of the main environmental factors that act on plants, affecting physiological processes such as germination and vigor, growth, photosynthesis, water and nutrients uptake, among others [1]. When seeds are exposed to temperature stress during imbibition process occur dramatic changes in the reorganization and function of the plasma membrane impairing the stability and functional structure of the membrane resulting in the decrease on germination and embryo death [2][3]. In plant, stress triggers wide response that extends from the change of gene expression and cell metabolism to changes in growth rate and productivity. The organism's reaction is a function of plant capacity to produce effects opposite to the action of stressors [4]. Aim: the purpose of this study was to evaluate high dilution effect of Arsenicum album on physiological variables of germination and growth of sorghum. Material and Methods: The experiment was conducted at the Laboratory of Physiology and Homeopathy at Universidade Estadual de Maringá - UEM. Arsenicum album 6x matrix was acquired in homeopathic laboratory. From matrix, other dilutions were prepared according to Brazilian Homeopathic Pharmacopoeia [5] with the homeopathic remedies prepared in distilled water (1/10) and succussed by 100 times in mechanical arm (50-Denise Model Autic). For cold test, 50 seeds were distributed on germitest paper moistened to 2.5 times the weight of paper under different dilutions of A. album (9, 12, 18, 24 and 30x) with four replications. The control consisted of distilled water. After sowing, the rolls were placed in plastic bags and sealed, and lead in BOD-chamber at 10°C for 7 days. After this period, the rolls were removed from plastic bags and transferred to BOD-chamber at (25 ± 2)°C, arranged at random where they remained for seven days. Germination percentage (GP%) were evaluated according to Rules for Seed Analysis [6]. The length of primary roots (LPR) and length of hypocotyl (LH) were determined only for seedlings. The total length seedlings (TLS) was calculated as the sum of the lengths of hypocotyl (LH) and primary root (LPR). The fresh biomass (FB) of the seedlings were obtained by removing from their cotyledons, and then weighed on an analytical balance. The dry biomass (DB) was obtained after drying at (80 ± 1)°C for 72h. The experimental design was completely randomized. We adopted the double-blind procedure, thereby avoiding possible researcher interference. Data were subjected to analysis of variance and means compared by Scott-Knott (P ≤ 0.05). Results: Seed exposure for seven days to cold stress at 10º C inhibited the germination percentage (GP%). Dilutions 9 and 18x showed the lowest germination percentage (Figure 1A). The cold inhibited the total length of hypocotyls (LH) the length of the seedlings (TLS), with the lowest values observed in seeds treated with dilution 24x (Figures 1B and 1C). Fresh biomass production of seedlings (FB) also was reduced the dilutions 9, 12 and 24x (Figure 1D). Seedlings treated with the dilution 24x reduced the dry biomass production (DB) (Figure 1E). Conclusions: We can conclude that homeopathy Arsenicum album 24x reduced the germination percentage, the length, fresh and dry biomass of sorghum. Probably the cause of this reduction is the lower absorption/water content in the system. The reduction in water content can be the cause lower values for the variables mentioned. However, the inhibitory action of the 24x dilution in water content is not yet known and will be one of the goals of future work.