INFLUENCE OF THERMAL REGIME OF SOIL ON THE SULFUR (S) AND SELENIUM (Se) CONCENTRATION IN POTATO PLANTS

Abstract

Three consecutive years of field experiments were carried out to investigate the effect of different root temperatures, induced by the application of mulches on the concentration of sulfur (S) forms (organic-S, total-S and SO4(2-)) and Se in different organs of potato plants (roots, tubers, stems and leaves). Four different plastic covers were used (T1: transparent polyethylene; T2: white polyethylene; T3: white and black coextruded polyethylene, and T4: black polyethylene), using uncovered soil as control (T0). The different treatments had a significant effect on mean root temperatures (T0 = 16 degrees C, T1 = 20 degrees C, T2 = 23 degrees C, T3 = 27 degrees C and T4 = 30 degrees C) and induced a significantly different response in the S forms and Se concentration, showing the T3 treatment (27 degrees C) the greatest concentration of total S and organic S in the stems and leaflets. The Se reached higher levels in the roots and tubers in T3. With regard to possibilities in phytoremediation, it is necessary to control the thermal regime of the soil to optimize the accumulation of elements.

Sulfur, chromium, and selenium accumulated in Chinese cabbage under direct covers

“…Previous findings from experiments of Cr distribution in plants indicated that only a small proportion of Cr absorbed is translocated to aerial parts (Chandra et al, 1997;Baghour et al, 2002;Gardea-Torresdey et al, 2004). In Chinese cabbage, the total Cr content per plant in T 1 surpassed 0.22% (Table 2), without the appeareance of phytotoxic symptoms.…”

“…The levels were not high enough to be considered as a Se-accumulator (!25 mg Se kg K1 d.w; Mazzafera, 1998;Ellis and Salt, 2003), and Se concentrations in all treatments did not reach toxic levels that would be considered detrimental to human health (Bañuelos et al, 1997;Baghour et al, 2002).…”

“…Sulfur, in its reduced form, plays an important role in plant growth and in the regulation of plant development (Bick and Leustek, 1998;Singh, 1999). Plants requiring high concentrations of S, such as Brassica species, will concomitantly absorb other available elements in the soil, either non-essential elements like selenium (Se) or toxic elements, such as chromium (Cr) (Baghour et al, 2001(Baghour et al, ,2002Gardea-Torresdey et al, 2004), which may inadvertently enter the food chain posing considerable health risks to humans and animals (Bañuelos and Mayland, 2000;Ellis and Salt, 2003;Pillay et al, 2003).…”

Chemical and biological characterisation of nutraceutical compounds of broccoli

“…Data has demonstrated that Se in soil can be reliably transferred to plants and ultimately to humans, and the Se uptake from soil and accumulation in plants is affected by soil type, soil humidity and sulphur status, soil temperature [111], and soil and air temperature, light conditions and humidity, as found in Chinese cabbage (B. rapa L. [Pekinensis group]) [112]. Broccoli (B. oleracea var.…”

Increased plasma selenium levels correlate with elevated resistance of Heliothis virescens larvae against baculovirus infection

“…In support of this hypothesis, plant derived inhibitors of phenoloxidase have been documented (Dowd, 1988(Dowd, , 1999Kubo et al, 2003) leading to speculation that insects feeding upon these compounds would exhibit suppressed melanization capabilities, and consequently be immunosuppressed Ourth, 2004;Shelby and Popham, 2006). Soil Se levels vary by geographic region and this variation correlates with the Se status of large herbivores such as beef cattle (Baghour et al, 2002;Hintze et al, 2002). Dietary Se was assimilated from selenate irrigated alfalfa by the larval beet armyworm, Spodoptera exigua, to selenite and to selenomethionine (Vickerman et al, 2004).…”