Leaf morphoanatomy of species tolerant to excess iron and evaluation of their phytoextraction potential

Abstract

Setaria parviflora (Poir.) Kerguélen and Paspalum urvillei Steudel are grasses that grow naturally in a soil with high iron contents. This study aimed to characterize morphoanatomically and histochemically the iron phytotoxicity on leaves and evaluate the phytoextraction potential of these grasses. Saplings were cultivated in hydroponic solution with and without excess Fe-EDTA. Regarding measurements taken on leaves, reduction was observed among treatments of Fe-EDTA on height values of abaxial epidermis and bundle sheath in both species. As for iron histolocalization, stronger reaction was observed in leaves of S. parviflora, in comparison with P. urvillei. Anatomical damage, such as protoplast retraction, irregular xylem, changes in cell volume, and cell collapse, and visual symptoms, like leaf bronzing, chlorosis, and necrosis, were similar in both species when exposed to excess iron; however, P. urvillei showed more severe damage. This species accumulated more iron in shoots than S. parviflora and therefore is more favorable for use in phytoextraction. The root system of both species accumulated higher iron concentrations in relation to shoots.

Arsenic accumulation in Brassicaceae seedlings and its effects on growth and plant anatomy

“…An apparent increase in the number of root lateral ramifications was the only visible morphological alteration, which reinforces the importance of anatomical studies for the precocious diagnose of the damage caused by arsenic or other pollutants (Sant' Anna-Santos et al, 2007;Tuffi-Santos et al, 2009;Silva et al, 2005;Siqueira-Silva et al, 2012;Santana et al, 2014).…”

“…Plant anatomy allied to morphological analyses is important in studies on environmental pollutants as it provides prognostic information on the deleterious effects that they may have on the studied plant species (Sant'Anna-Santos et al, 2006;Shaibur and Kawai, 2009;Santana et al, 2014). The low cost of these techniques, the reliability of the results and the rapidity with which these results are obtained make such techniques applicable in analyses of the quality of large-scale produced crop species (Shaibur and Kawai, 2009), such as several representatives of the Brassiaceae.…”

Morphoanatomical responses induced by excess iron in roots of two tolerant grass species

“…P. urvillei and S. parviflora are both species that tolerate and accumulate in their root iron amounts above the toxicity limit (500 mg kg −1 ) (Marschner 1995), as already verified by Santana et al (2014), who studied the iron effects on these two species with the same exposure time as the one used in our study. The high iron content caused morphological and anatomical alterations in roots of the two studied species.…”

“…Besides tolerating high Fe concentrations in the substrate, both species accumulate in their tissue iron contents above the toxicity limit, which according to Marschner (1995) is 500 mg kg −1 , without altering their growth (Araújo et al 2014). Species exposed to high iron concentrations may exhibit characteristic visual toxicity symptoms (Santana et al 2014), even when not presenting changes in their growth (Araújo et al 2014).…”

Differential physiological responses in rice upon exposure to excess distinct iron forms

“…Iron excess in leaf tissues caused prominent morphoanatomical changes in the rice leaves. The leaf bronzing observed in both cultivars studied is a classic symptom of iron toxicity (Engel et al 2012;Santana et al 2014). Cellular collapse due to injuries of the epidermal and mesophyll cells, and the reduction in the thickness of leaf blade (Fig.…”