Tolerance of Eucalyptus and Pinus seedlings to exchangeable Aluminium

Abstract

Tolerance to acid soil is an important trait of Eucalyptus and Pinus species introduced into commercial forestry plantations in tropical ecosystems. The objective of this study was to evaluate the effect of the exchangeable Al on growth of the seedlings of two species and one hybrid of Eucalyptus and two species of Pinus. We also wanted to identify the role of the root cation exchangeable capacity (CEC) on Al tolerance. The experiment was conducted under controlled conditions in a greenhouse. The soil used was collected from the top layer of a red yellow Oxisol, from the Brazilian savanna region. The treatments consisted of different rates of P and the presence or absence of liming with CaCO 3 and MgCO 3. The species of Eucalyptus and Pinus showed no growth differences between the treatments. For all species, a higher density of fine roots was found in treatments with lower levels of bases and a higher Al exchangeable concentration. The Pinus species had a higher root CEC than the Eucalyptus species, which had a lower leaf Al concentration. Al concentration in the fine roots was 50 fold greater than in the leaves of all species. Similar to Al, concentrations of Fe, Cu and Zn in the roots were significantly higher than in the leaves in all species. In contrast, higher Mn concentration was found in the leaf tissue. This may lead species of Eucalyptus and Pinus to be more susceptible to Mn than to Al toxicity.

Aspects of soil fertility and nutrition of Pinus taeda L: A review

“…Aluminum (Al 3+ ) is an element that should always be observed in the nutrition of forest species, because when present in high concentrations in the soil it is considered a toxic element and can limit crop productivity in acidic soils (GOMES et al, 2019). Pinus is considered a species tolerant to the presence of Al 3+ in the soil, presenting adequate development rates, even in acidic soils (MOYER-HENRY et al, 2005;ROCHA et al, 2019).…”

“…However, at low concentrations (<370 µmol L -1 ), Al 3+ can be beneficial for Pinus development (HUANG; BACHELARD, 1993). At higher concentrations of Al 3+ in soil solution, it can be considered toxic, and can compromise and reduce the growth of the species (ROCHA et al, 2019). In general, the toxic effect of Al 3+ in plants is associated with a reduction in the development of the root system, since the main tolerance mechanism of Pinus is to avoid Al 3+ uptake (GOMES et al, 2019).…”

“…At higher concentrations of Al 3+ in soil solution, it can be considered toxic, and can compromise and reduce the growth of the species (ROCHA et al, 2019). In general, the toxic effect of Al 3+ in plants is associated with a reduction in the development of the root system, since the main tolerance mechanism of Pinus is to avoid Al 3+ uptake (GOMES et al, 2019). If this occurs, the thin roots end up exploring a smaller soil volume and, therefore, the plants express low efficiency in nutrient uptake and high susceptibility to water stress (ROCHA et al, 2019).…”

Availability of copper and zinc as affected by soil acidity in >i<Eucalyptus>/i< plantation

“…3) probably reflects the greater contribution to plant uptake of these metals from the soil and export to the xylem, orchestrated by various enzymatic transporters (Dimkpa et al 2020). Other study suggests that high root concentrations of Fe, Cu and Zn in relation to leaf were adsorbed to root cation exchange capacity, limiting their entry into the symplast (Gomes et al 2019). The higher concentration, accumulation, and distribution of Mn in leaves (Fig.…”

“…However, liming potentially have side effects in soil Cu and Zn availability for plant uptake . This hypothesis is based on the fact that lime is rich in Ca and Mg contents and, once applied into the soil, H + and Al + availability is reduced (Gomes et al, 2019;. Accordingly, liming increases pH levels and contributes to higher precipitations of Cu and Zn bound to carbonates or adsorbed to compounds rich in the Ca Jiménez-Cárceles et al, 2008).…”