Responses of restinga plant species to pollution from an iron pelletization factory

Abstract

Byrsonima sericea DC. (Malpighiaceae), Cordia verbenacea DC. (Boraginaceae) andPsidium guineense SW. (Myrtaceae) were studied in two experimental sites: a restinga forest fragment, near an iron pelletization factory (mining area) and a restinga conservation unit "Paulo César Vinha State Park". The aims were verify the effects of emissions from a pelletization factory on some anatomical and physiological parameters and on absorption and accumulation of particulate iron by the leaves. A protocol was adjusted using Prussian blue reaction to histochemical detection of iron.Comparing the same species in two locals, C. verbenacea was the greatest accumulator of metallic iron, whereas B. sericea presented greater content of sulphur in mining area. The greater leaf contents of metallic iron may be related to the adhesion of the particles deposited on the leaves and to the characteristics of the covering tissue and the leaf. The foliar parameters evaluated in addition to soil analysis and atmospheric precipitation data indicated that the effects of particulate deposition occurred due foliar uptake. Structural characteristics such as peltate trichomes of leaf abaxial surface in B. sericea and hypodermis observed in B. sericea (one layer) and P. guineense (3-4 layers), probably formed a barrier lessening the penetration of metallic iron into the mesophyll as evidenced by the lower iron leaf content and iron accumulation in trichomes observed in these two species. In leaves of C. verbenacea occurred a positive reaction for iron in trichomes, epidermic cells at both faces, stomata, some xylem cells, collenchyma and endodermis at the midrib, and mesophyll tissues. The obtained data indicated that the unit conservation is also under pollution impact.

Early detection of injuries in leaves of Clusia hilariana Schltdl. (Clusiaceae) caused by particulate deposition of iron

“…Silva et al (2006) have also suggested an internal temperature increase in leaves of Cordia verbenacea and Psidium guineense growing near a pelletizing industry, as probable effect of stomata obstruction.…”

“…This observation corroborates with the data found by Silva et al, (2005) when characterizing the structural alterations caused by simulated acid rain in C. hilariana, in which the injury developed from the epidermis of the abaxial surface of the leaf. Stomata alterations caused by the deposition of particulate matter cause a physiological disturbance (FARMER, 1993;INOUE;REISSMANN, 1994;SILVA et al, 2006;PEREIRA et al, 2009), besides acting as an entrance pathway to the pollutant causing an increase in total concentration of metallic elements in the leaf tissues (GRANTZ et al, 2003). The histological organization of C. hilariana was kept unaltered after 45 days of continuous exposure to SPM Fe , presenting little structural injury.…”

“…In plant species, the toxicity by iron can be of two types: direct toxicity, caused by the accumulation of high levels of iron in the plant tissues (OLALEYE et al, 2001;SILVEIRA et al, 2007), and indirect toxicity, caused by multiple nutritional disorder resulting from deposition iron-shaped plate in the roots (LIU et al, 2008;SIQUEIRA-SILVA et al, 2012).…”

“…Additionally, the obstruction of the stoma may cause the increase of the leaf temperature, the alteration of the transpiratory rate (PEREIRA et al, 2009) and anatomical and ultrastructural modifications in leaf tissues organization (SILVA et al, 2006). Symptomatological, physiological, and biochemical parameters have been often used to evaluate the effects of the SPM Fe deposition on plant species (LOPES et al, 2000;OLIVEIRA et al, 2007;KUKI et al 2008a,b;NEVES et al, 2009;PEREIRA et al, 2009).…”

“…The morphoanatomical structure of leaves from species subjected to SPM Fe can contribute to the determination of their susceptibility to pollutants (PALING et al, 2001;SILVA et al, 2006). Characters of the epidermis, epicuticular wax deposition pattern, cuticle topography, epidermic cells shape, stomata distribution and position in relation to the other epidermal cells, are among the parameters involved in the plant responses to pollutants (SILVA et al, 2005;SANT'ANNA-SANTOS et al, 2006a,b, 2007BALASOORIYA et al, 2009;KARDEL et al, 2010;RAÍ et al, 2010;MESQUITA et al, 2011).…”