In Brazil, sugarcane is grown in large areas. Weed control in sugarcane fields is done by chemical method, since it is more efficient and less expensive. In this method, herbicides that persist in the environment for long periods are used, among which there are hexazinone and diuron, which are applied in mixtures marketed by the industry. This research evaluated the sorption and desorption of hexazinone and diuron applied alone and in mixture, in two samples of Red-Yellow Latosols (LVAG and LVAV) and a Organosol (OR), with and without manure. Sorption isotherms were built using the batch equilibrium method and the identification and quantification of herbicides was obtained through a high-performance liquid chromatography (HPLC) with UV-Vis detector. There were high diuron sorption coefficients (Kf) in the soils. The hexazinone Kf values found were low in LVAG and LVAV soils, and they were high ground only in OR. In all soils, diuron and hexazinone showed higher Kf values when mixed. There was a direct relation between the addition of manure to the substrate and the Kf values . Higher desorption values (Kfd) in relation to those of sorption in LVAG and LVAV soils indicate gradual release of these herbicides in the soil solution when using organic fertilizer, showing increased sorption and desorption of these molecules; this is accentuated when they are mixed. In the Organosol, desorption was very low, and cannot be quantitated by the used method. It is possible to conclude that the incubation of LVAG and LVAV soil with manure helps both the process of sorption and desorption of herbicides. However, sorption and desorption in the Organosol is high indicating very low agrochemicals such strong bonds with soil colloids.

In this study, basil (Ocimum basilicum L.) seedlings were intoxicated with Cd2+ and cultivated using a 5% v v–1 Hoagland nutrient solution. Desorption electrospray ionization mass spectrometry imaging (DESI-MSI) was used to identify different compounds on basil leaves (without and with 10 μmol L–1 Cd2+). DESI-MSI analysis identified 28 images of ions with high accuracy (mass deviation < 1.8 ppm) in contaminated and uncontaminated leaves. The biomarkers formed due to Cd external stress under controlled laboratory experiments were putatively identified in contaminated leaves as jasmone, hexose sugars, salvigenin, flavonoids (C18H14O7 and C21H22O10), and fatty acyl glycosides (C18H28O9). The accumulation of Cd occurred preferentially in the roots but also on the stems and leaves. The methodology to quantify Cd in basil organs was optimized and validated using an ultrasound-assisted micro-extraction procedure. Limits of detection and quantification were 6 and 17 μg L–1, respectively, with a precision better than 7.5 %, obtained by fast sequential flame atomic absorption spectrometry (FS FAAS). The standard reference material of spinach leaf (SRM NIST 1570a) presented a recovery of 101 ± 8 %. DESI-MSI was for the first time employed to examine the behavior of metabolites in plants maintained under stress conditions by the exposure to high levels of cadmium.

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The ionomic response of basil leaves, stems, and roots to Cd2+ was evaluated in seedlings grown in a hydroponic system for 15 days. Ions were quantified by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Cd accumulated mainly in roots while Be, Li, Ca, Mg and Sr in leaves and K and Mn in stems. Compared to the control group, basil seedlings treated with Cd2+ accumulated higher Ca, Cu, Mn, Sr, and Zn contents in roots, even when exposed at low levels. Pearson positive correlations between Cd and essential and nonessential elements were mostly observed in leaves and roots (p &lt; 0.05). On the other hand, negative correlations were observed mainly in stems with all elements, except Ba, Li, Sr, and Zn. Principal component analysis (PCA) showed an ionomic discrimination between leaves, stems, and roots, with Cd strongly correlated to Zn, Cu and Sr.