Plant growth, nutrients and potentially toxic elements in leaves of yerba mate clones in response to phosphorus in acid soils

Abstract

Native to subtropical region of South America, yerba mate is responsive to P under some conditions, but the degree of influence of genetic and soil on the growth and composition of the leaf is unknown. The aim of study was to evaluate plant growth, nutrients and potentially toxic elements in leaves of yerba mate clones in response to P application in acid soils. In greenhouse condition, two yerba mate clone seedlings were grown (210 days) in pots, each clone in a completely randomized design in factorial scheme (with and without P; four acid soils). The elemental composition of leaves and the growth of plants were determined. Phosphorus promoted plant growth, but this was not accompanied by increased P in leaf tissue in all conditions tested. The P effect on the elemental composition varied: decrease/null (N, K, Mg, Mn, Cu, Ni, B, Mo, Al, Cd); increase/null (C/N, C, Ca, Fe, V); increase/decrease/null (Zn, Ba, Pb) and; null (Cr). The soils affect the elemental composition of the leaves, especially Mn, with accumulation greater than 1000 mg kg -1 . The Ba, Pb, Al and Zn in the leaves varied among clones. Yerba mate response to P was affected by edaphic and plant factors.

Soil Chemical Attributes and Their Influence on Elemental Composition of Yerba Mate Leaves

“…The aluminum concentrations found in the yerba mate leaves (Table 2) were similar to those reported in previous studies (REISSMANN et al, 1999;HEINRICHS;MALAVOLTA, 2001;CALDEIRA et al, 2006;OLIVA et al, 2014;BARBOSA et al, 2018). According to Reissmann et al (1999), yerba mate is a species that is Al-tolerant.…”

“…The strong correlation between Fe and V ( Table 3) that we observed was similar to the results of Barbosa et al (2018). In acidic soils, although V is predominant in its ionic form (VO2 + ), it presents a number of oxidation states that have ionic radiuses similar to Fe 2+ (0.74 Å) (KABATA;PENDIAS, 2011).…”

“…The average concentration of Ni (Table 2) was less than that reported by Heinrichs and Malavolta (2001) for processed yerba mate, but higher than that observed by Barbosa et al (2015) for leaves and fruits of four yerba mate varieties. For V, the concentrations measured were higher than that reported by Barbosa et al (2015) and Barbosa et al (2018). Vanadium has a number of health benefits for humans, such as to control the sugar levels in the blood in diabetic people, anti-tumoral and anti-carcinogenic activity, although high dosages can have negative effects (KORBECKI et al, 2012).…”

“…However, the variations in pH provided little support for the large variation in the Mn level that was observed. Barbosa et al (2018) reported that elevated concentrations of Mn in leaves were dependent on its availability, as well as the amount of low crystalline compounds containing Mn in the soil.…”

“…A number of factors control the elemental composition of yerba mate leaves, for instance, the genetics (BENEDETTI et al, 2017;BARBOSA et al, 2018), leaf age, time between harvesting, index of light (JACQUES et al, 2007), variation between leaves and fruits (BARBOSA et al, 2015), and soil attributes (REISSMANN et al, 1999;CARNEIRO, 2004;BARBOSA et al, 2018). Considering that yerba mate leaves are meant for human consumption, it is necessary to identify its elemental composition and its relationship with soil proprieties, because the soil chemistry can determine the elemental composition and consequently the raw material quality.…”