Nitrogen Effect on Growth-Related Parameters and Evaluation of Portulaca oleracea as a Phytoremediation Species in a Cr(VI)-Spiked Soil

Abstract

In a pot experiment, we assessed the potential of purslane (Portulaca oleracea) as a phytoremediation species in Cr(VI)-contaminated soils. We focused on the evaluation of phytotoxic Cr(VI) effects at concentrations reaching 150 mg Cr(VI) kg−1 and the possible stress amelioration effect of nitrogen on Cr(VI)-stressed plants. Treatments were T-0 (control), T-1 (25 mg Cr(VI) kg−1), T-2 = 50 mg kg−1, T-3 = 100 mg kg−1, and T-4 = 150 mg kg−1. We measured Cr(VI) concentration in aerial and root tissues, a series of parameters related to photosynthesis and plant growth, phosphorus aerial plant tissue content, and we also calculated indices (ratios) related to leaf growth and above ground tissue water content. Cr(VI) almost exclusively was found in root tissues; all physiological and growth parameters studied were severely affected and plants selectively accumulated phosphorus in aerial plant tissues with increasing Cr(VI) soil concentrations. On the other hand, N amendment resulted in improved plant features in some of the measured parameters: chlorophyll index was improved with added N at T-2, plant height was significantly higher at T-0, T-1, and T-2, and aerial dry weight and leaf area was higher at T-0; these effects indicate that added N did increase P. oleracea potential to ameliorate Cr(VI) toxic effects. We conclude that purslane showed a potential as a possible species to be successfully introduced to Cr(VI)-laden soils, but more research is certainly necessary.

The Response of Purslane (Portulaca oleracea) to Soil-Added Pb: Is It Suitable as a Potential Phytoremediation Species?

“…One week prior to the harvest date, we measured plant height (cm), and photosynthetic rate (µmol CO 2 m −2 s −1 ) at a constant light intensity of 250 µmol cm −2 s −1 using the LI-Cor LI-6400XT Portable Photosynthesis System (LI-Cor, Lincoln, NE, USA)), whereas chlorophyll content (SPAD index) was measured using the OPTI-SCIENCES CCM-200 plus chlorophyll content meter (Opti-sciences, Hudson, NH, USA). Moreover, we measured the leaf area with the use of LI-3100C Area Meter (LI-COR Biosciences; Hellamco S.A., Athens, Greece) (all plant measurements are described in detail by [ 13 , 22 ]. At the end of the experiment, the aerial plant biomass was cut 2 cm above the soil surface and separated into leaves and stems.…”

“…Purslane ( Portulaca oleraceae ) is a wild edible plant that can be commercially cultivated in pristine soils and traded as it can be used as a gourmet raw or cooked salad. It has recently been tested as a potential species for use in phytoremediation if introduced to Cr(VI)-contaminated soils [ 13 , 14 ]. Moreover, the phytoremediation potential of the species has been reported by Kale et al [ 15 ], who suggested that hydroponically grown purslane may tolerate a high accumulation of Cr through the accumulation of proline and enhanced capacity of scavenging radical oxygen species.…”

Mine Site Restoration: The Phytoremediation of Arsenic-Contaminated Soils

“…For example, in rice production, the highest dry weight yield was most impacted by sufficient N availability; further, lowest yields were observed with N deficiency [122]. A study by Thalassinos et al [126] revealed that the addition of N significantly increased the plant height of Portulaca oleracea during the phytoremediation of Cr(VI)-contaminated soils.…”

Soil, Water and Nitrates Management in Horticultural Production

“…Thalassinos et al [7] analyzed the potential of purslane (Portulaca oleracea) as a phytoremediation species in Cr(VI)-contaminated soils. They concluded that purslane showed potential as a species to be successfully introduced to Cr(VI)-laden soils.…”