Morpho-Physiological and Metal Accumulation Responses of Hemp Plants (Cannabis Sativa L.) Grown on Soil from an Agro-Industrial Contaminated Area

Abstract

Hemp is a promising plant for phytomanagement. The possibility to couple soil restoration to industrial crop cultivation makes this plant attractive for the management of contaminated sites. In this trial, Cannabis sativa L. plants were grown in a greenhouse on soils from two sites of “Valle del Sacco” (Lazio Region, Italy), a wide area contaminated by agro-industrial activities. One site was representative of moderate and diffuse metal(loid) multi-contamination, above the Italian concentration limit for agriculture (MC—moderately contaminated). The second site showed a metal(loid) content below the aforementioned limit, as a typical background level of the district (C—control). After 90 days, biometric and physiological parameters revealed satisfactory growth in both soil types. MC-grown plants showed a slight, but significant reduction in leaf area, root, and leaf biomass compared with C-grown plants. Chlorophyll content and chlorophyll fluorescence parameters, namely the quantum yield of primary photochemistry (Fv/Fm) and the Performance Index (PIABS), confirmed the good physiological status of plants in both soils. Metal(loid) analyses revealed that As, V, and Pb accumulated only in the roots with significant differences in MC- and C-grown plants, while Zn was found in all organs. Overall, preliminary results showed a satisfactorily growth coupled with the restriction of toxic metal translocation in MC-grown hemp plants, opening perspectives for the phytomanagement of moderately contaminated areas.

Root and Shoot Response to Nickel in Hyperaccumulator and Non-Hyperaccumulator Species

“…Consistent with the biomass results, and consistent with other plants able to accumulate metals [ 61 , 62 ], the maximum primary photochemical efficiency of PSII, Fv/Fm, and the performance index (PI) [ 63 ] do not differ in the hyperaccumulator species at increasing Ni concentrations, while it significantly declines in A. montanum. This could be due to the great sensitivity to the fluctuations of environmental abiotic factors [ 64 ], such as Ni stress.…”

Potential of hemp (Cannabis sativa L.) for paired phytoremediation and bioenergy production

“…Similarly, hemp grown in soils with moderate contamination of metal(loid)s As, Pb, V, and Zn (22.6, 115, 106.7, and 92.8 ppm, respectively) had Citterio et al (2003) 0.14-0.30 mg kg −1 (leaf/stem) 1.69-2.56 mg kg −1 Di Candilo et al (2004) 0.8-3.5 ppm (leaf/stem/seed) Linger et al (2002) 0-3 mg kg −1 (shoot only) Meers et al (2005) 11.4-33.3 µg g −1 (shoot only) 217-481 µg g −1 Shi et al 20121.3-4 mg kg −1 (shoot only) Mihoc et al 20122.47-32,293 µg g −1 (leaf/stem; seedling) 547-33,457 µg g −1 (seedling) Petrová et al 2012151 mg kg −1 (leaf only) Ahmad et al 2016Chromium 1.2-1.4 µg g −1 (leaf only) 6.2-9.0 µg g −1 Citterio et al 2003Copper 15-80 mg kg −1 (shoot only) Meers et al (2005) 20.9-29,914 µg g −1 (leaf/stem) 1026-16,240 µg g −1 Petrová et al 20121530 mg kg −1 (leaf only) Ahmad et al 2016Lead 0.21-1.12 mg kg −1 (leaf/stem) 1.30-1.88 mg kg −1 Di Candilo et al 20041.8-22.4 ppm (leaf/stem/seed) Linger et al 20021-7 mg kg −1 (shoot only) Meers et al 20051.38-9627 µg g −1 (leaf/stem; seedling) 3738-66,280 µg g −1 (seedling) Petrová et al 2012Nickel 7.1-52.1 µg g −1 (leaf/stem) 35.8-321.8 µg g −1 Citterio et al (2003) 6.9-63.6 ppm (leaf/stem/seed) Linger et al 20025-23 mg kg −1 (shoot only) Meers et al (2005) 123 mg kg −1 (leaf only) Ahmad et al 2016Radium 0.28-0. yields and morphological traits comparable to plants grown in control soils. There were no statistically significant differences between the stem and inflorescence yields, the plant height, or the stem diameter of hemp cultivated in moderately contaminated soils when compared to cultivation in control soils (Pietrini et al, 2019). This indicates that low levels of contamination are not detrimental to the overall aboveground biomass yield of the crop, since the components of stem size/ yield compose a large fraction of the total hemp plant mass.…”

Linking Bioeconomy to Redevelopment in Contaminated Sites: Potentials and Enabling Factors

“…There is a wide variety of knowledge and technological expertise needed for bioeconomy-related activities, and the challenge to apply bioeconomy principles to contaminated sites includes research-and industry-driven aspects and demands innovation in bioeconomy value chains. As an example, there are still relevant gaps of knowledge on the effects of the presence of contaminants on biomass quality and conversion/valorization potential (Bianconi et al, 2011;Pietrini et al, 2019). Preliminary studies on processes for biomass treatment coming from phytoremediation activities and consequent valorization into a biorefinery perspective also using microorganism (Sotenko et al, 2017) have been undertaken with the aim to pave the way for successful commercialization of bio-based products and services from contaminated areas.…”

“…The perimeter of the contaminated area (Site of National Interest -SIN) was later enlarged to cover over 8,000 hectares included in 19 municipalities between the Provinces of Rome and Frosinone, where several industrial clusters are located. Since 2012 bioremediation approaches have been tested both in lab and pilot scale (Bianconi et al, 2011;Pietrini et al, 2019) with the double aim to remediate from contamination and turn the system into a sustainable value chain. Despite this serious situation, no political frameworks have been developed in the long term in the Region.…”