ROOT ZONE TEMPERATURE AFFECTS THE PHYTOEXTRACTION OF Ba, Cl, Sn, Pt, AND Rb USING POTATO PLANTS (SOLANUM TUBEROSUML. VAR. SPUNTA) IN THE FIELD

Abstract

Three consecutive years of field experiments were conducted to investigate how different root-zone temperatures, manipulated by using different mulches, affect the phytoextraction of Ba, Cl, Sn, Pt and Rb 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 plants as control (T0). The different treatments had a significant effect on mean root zone temperatures (T0 ¼ 16 C, T1 ¼ 20 C, T2 ¼ 23 C, T3 ¼ 27 C and T4 ¼ 30 C) and induced a significantly different response in Ba, Cl, Sn, Pt and Rb concentration and accumulation. The T3 treatment gave rise to the greatest phytoextraction of Ba, Pt, Cl and Sn in the roots, leaflets and tubers. In terms of the relative distribution of the phytoaccumulated elements (as percentage of the total within the plant), Pt and Ba accumulated mainly in the roots whereas Rb, Sn and Cl accumulated primarily in tubers, establishing a close relationship between the biomass development of each organ and phytoaccumulation capacity of metals in response to temperature in the root zone.

Ionomic response ofLotus japonicusto different root-zone temperatures

“…1). Similar results were also reported for potato (Baghour et al 2001(Baghour et al , 2002a(Baghour et al , 2002b(Baghour et al , 2002c(Baghour et al , 2003, Brassica napus (Ye et al 2006) and tropical cucurbitaceous plants (Zhang et al 2008): within the RZT range of 20-27 C, the total biomass increased in plants, while outside this range the dry weight fell. Effect of low RZT has been previously emphasized; Engels and Marschner (1990) found that low root temperatures not only delayed root growth but also reduced the shoot growth of corn plants.…”

“…Baghour and co-workers demonstrated that 23-27 C soil temperature was optimum for the uptake of most essential and some non-essential elements such as aluminum (Al), As, barium (Ba), Cd, nickel (Ni) and lead (Pb) (Baghour et al 2001(Baghour et al , 2002a(Baghour et al , 2002b(Baghour et al , 2002c(Baghour et al , 2003. These studies also showed that RZT < 20 C, considered sub-optimal for most plants (Zhang et al 2008;Adebooye et al 2010), exacerbates growth as well as nutrient uptake.…”

“…Baghour and coworkers reported that 23-27 C was ideal for uptake of most element (Baghour et al 2001(Baghour et al , 2002a(Baghour et al , 2002b(Baghour et al , 2002c(Baghour et al , 2003. Engels and Marschner (1990) reported that N, P and K concentrations in shoots of maize decreased at low .…”