<i>Urochloa brizantha</i> cultivated in aluminum-toxic soil: Changes in plant growth and ultrastructure of root and leaf tissues

Abstract

Brazilian soils destined for fodder production are infertile and acidic and contain toxic levels of aluminum (Al), which cause a reduction in growth of the root system and aerial plant parts. The main aim of the present pot trial was to determine ultrastructural and developmental changes in root and leaf tissues of Urochloa brizantha, when grown in an acid Oxisol containing varying levels of Al. The experimental design was a 3 × 5 factorial arrangement, involving 3 cultivars of U. brizantha (Marandu, Paiaguás and Piatã) and 5 concentrations of Al in the soil (0.2, 0.4, 0.8, 1.6 and 3.2 cmol/dm3), with 4 replications; a total of 60 pots. All cultivars responded negatively to increasing Al concentration in the soil, even in small amounts. Root ultrastructures were damaged even at concentrations of 0.4 cmol Al/dm3, primarily in the conducting tissues (xylem and phloem) and epidermal cells. Shoot development and leaf tissues were also negatively affected. In general, plant development and ultrastructure of root and leaf tissues in all 3 cultivars of U. brizantha were impaired when grown in the presence of Al at doses &gt;0.2 cmol/dm3 in the soil.

Característica bromatológica y morfológica de las plantas forrajeras

“…The lower concentration of minerals in the plant may occur due to a minor concentration of minerals in soil, a diminished genetic capacity of mineral accumulation, or even an indication of smaller needs of the plants to its growth regarding minerals. Similarly, higher concentrations, even in toxic levels, are indicative of its excess in soil, plant genetic capacity of higher accumulation, or greater need of minerals for its growth (Lisboa et al, 2021).…”

“…The thickness of adaxial cuticle (TAdC) and thickness of abaxial cuticle thickness (TAbC) did not present significant difference in the studied species. Biotic and abiotic stress may influence ihe epidermal thickness of leaves (Lisboa et al, 2021). As the main functions of these issues are the protection of the vegetal' surface and gas exchange, including steam, plants that contain epidermis may protect their mesophile against several injuries (Carrizo et al, 2020).…”