Germination potential of Sesbania cannabina in 2 Chromium (Cr) spiked growth media

<p>Sediments of the banks of the Buriganga River, Bangladesh, are contaminated with heavy metals from industrial activity, especially Chromium (Cr). These carcinogens pose a serious risk to human and environmental health (Nargis et al., 2018). Sesbania cannabina, a leguminous fodder crop with rapid growth and high biomass production, is found to be naturally growing in these areas (Sarwar et al., 2015) and may have phytoremediation potential (Varun et al., 2017). This study aims to determine whether Sesbania cannabina can be grown from seed under chromium stressed conditions to establish this species as a possible phyto-extractor.</p><p>In this experiment toxicity testing of Chromium (K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>) on seed germination was carried out using two growth media: Murashige and Skoog basal medium (MS0); and filter paper (Whatman Grad 1), by top of media or top of paper method respectively. In all cases, seeds were germinated under controlled conditions; 12 h full spectrum light at temperature 28°C ± 1°C and relative humidity of ~ 75% for 5 days. Seeds were pre-treated with H<sub>2</sub>O<sub>2</sub> (6% v/v) for 5 minutes and primed with 65°C water for 5 minutes, before the addition of Cr. Under low Cr concentrations (0 to 50 ppm) there was no significant effect observed in germination or root length. Under high Cr concentrations 98-100% of seeds germinated in both growth media, but root length decreased to almost half that of controls in ≥ 500 ppm Cr, and root elongation was negligible or stopped in ≥ 1000 ppm Cr. Confocal micrographs (stained with propidium iodide) indicate that damage to the cell wall of lateral root tips of germinated seeds increased with the concentration of Cr. There was no significant difference observed between the two growth media.</p><p>Thus it can be concluded that Sesbenia cannabina can tolerate Cr contamination, and is able to germinate and grow in up to 500 ppm Cr. Given the ability of SC to grow in semi-arid to sub-humid climates, and a range of environmental conditions including seasonally submerged soils, there is great potential for SC to be adopted as a tool for phytoremediation of Cr contaminated soils in Bangladesh and elsewhere.</p>

Modeling the Emergence and Growth of Alligatorweed at Different Field Capacity Levels

ABSTRACT: A study focusing on different field capacity levels was planned in the Weed Science Lab, Department of Agronomy, University of Agriculture Faisalabad. Fresh alligatorweed was harvested from the Agronomy fields and cuttings (2 cm length) were made from it. These cuttings were placed at 25%, 50%, 75% and 100% field capacity levels in pots for 25 days. The results of the experiments revealed that at all field capacity levels, fragments of alligatorweed were able to sprout and grow. Increased moisture levels significantly increased the emergence ability and survival of the alligatorweed plants upto a certain level. Compared with the control (25% FC), emergence time of the sprouts in the maximum moisture regime (100% of FC) decreased by 40% (12.94 days vs.7.17 days). By contrast, the survival rate of the fragments decreased by 60% (5 vs. 1.75) although survival and growth rate increased at first with 50% FC and 75% FC. Maximum sprouting and growth were found at 50% field capacity. Field capacity does affect the sprouting capacity of alligatorweed fragments but it has only a little influence on growth parameters. The results suggest that alligatorweed can sustain dry conditions to a great extent and also has the ability to sprout and grow in fully submerged soils.