Early Growth Test Research Articles

Thermal treatment of petroleum-contaminated marine sediment according to oxygen availability and temperature: Product quality as a potential plant-growth medium

The sustainable management of dredged sediment from contaminated sites needs to consider the end-use of the treated sediment. In this regard, modifying conventional sediment treatment techniques to generate a product that is suitable for a range of terrestrial uses is necessary. In the present study, we evaluated the product quality of treated sediment as a potential plant-growth medium following the thermal treatment of marine sediment contaminated by petroleum. The contaminated sediment was subject to thermal treatment at temperatures of 300, 400, or 500 °C, and no, low, or moderate oxygen availability, and the resulting treated sediment was analyzed in terms of its bulk properties, spectroscopic properties, organic contaminants, water-soluble salts and organic matter, and the leachability and extractability of heavy metals. All operational combinations for the treatment process reduced the total petroleum hydrocarbon content of the sediment from 4922 mg kg−1 to lower than 50 mg kg−1. The thermal treatment process stabilized the heavy metals in the sediment, reducing the zinc and copper concentration by up to 58.9% and 89.6%, respectively, in the leachate from the toxicity characteristic leaching procedure. The hydrophilic organic and/or sulfate salt byproducts of the treatment were phytotoxic, but these can easily be removed by washing the sediment with water. By combining the sediment analysis results with experimental data from barley germination and early-growth tests, the end product was found to be of higher quality when higher temperatures and lower oxygen availability were employed in the treatment process. These findings demonstrate that it is possible to retain the natural organic resources of the original sediment by optimizing the thermal treatment, thus ensuring a suitably high product quality for use as a plant-growth medium.

Phytotoxicity assessment of biodegradable and non-biodegradable plastics using seed germination and early growth tests

Global production of plastics remains at the high level despite the SARS-Cov-2 pandemic. These are primarily petroleum-derived plastics but the contribution of bio-based plastics estimated at the level of 1% in the plastic market in 2019 is expected to be increasing. Simultaneously, the significant part of plastic waste is still disposed improperly and pollutes the environment making a threat to all living organisms.In this work three plastic materials, two bio-based biodegradable: polylactide (PLA) and polyhydroxybutyrate (PHB), and one petroleum-derived non-biodegradable polypropylene (PP) were studied towards their effects on seed germination and early growth of higher plants. The following plants were used as bioindicators: monocotyledonous plant - Sorghum saccharatum and two dicotyledonous plants: Sinapsis alba and Lepidium sativum. Plastics did not affect seed germination of higher plants even at the highest concentration tested (11.9% w/w) but their presence in soil acted in various ways on growth of the plants. Either no or inhibitive or stimulation effects on growth of roots or stems were noticed. It depended on the concentration and chemical composition of the plastic tested, and plant species. PHB and PLA more often caused to the inhibition of root growth than PP did. This phenomenon was observed in particular with regard to the dicotyledonous plants.Moreover, in the tests with the dicotyledonous plants (S. alba and L. sativum) the dose-response relations were usually determined as statistically relevant. Among these plants cress (L. sativum) occurred to be more sensitive and allowed for obtaining the dose-response dependence for both root and stem length, and, what is important, it took place in the case of each of materials tested. Therefore, cress is recommended to be used as a bioindicator in the assessment of the effect of plastics (petroleum-derived and bio-based plastics) on the early stages of growth of higher plants.

Plant-microbe-soil fertility interaction impacts performance of a Bacillus-containing bioproduct on bell pepper.

Limited information is available on the performance of plant growth-promoting inoculants or bioproducts under different soil nutritional or fertility conditions. Consequently, the objective of this study was to evaluate the effects of a commercially available Bacillus-containing bioproduct, Microlife Abundance, at concentrations of 5.5 and 6.5 log cfu/ml on early growth, fertilizer use-efficiency, and fruit yield of bell pepper (Capsicum annuum L.) under two different soil fertility conditions (25% and 100% recommended N rates). Two pot experiments were conducted with bell pepper: (a) a 4-week-long early growth test with inoculant treatments applied once at transplanting; and (b) a 13-week-long yield test with inoculant treatments applied at transplanting and again at first blossom-set. Results from the early growth test indicated that at both N fertilization levels, applying Abundance once at transplanting at 6.5 log cfu/ml rather than 5.5 log cfu/ml significantly increased root dry weight, total root length, root volume, root surface area, and total length of very fine roots compared with the noninoculated control by 20%, 13%, 17%, 15%, and 12%, respectively. In contrast to the early growth, results from the yield test showed that only at the 100% recommended N rate, applying Abundance twice at both concentrations significantly enhanced N fertilizer use-efficiency and marketable yield of bell pepper over the noninoculated control by 34% (5.5 log cfu/ml) and 30% (6.5 log cfu/ml). Therefore, the efficacy of the Bacillus-containing bioproduct Abundance in enhancing fertilizer use-efficiency and marketable yield of bell pepper varied between soil nutritional conditions, but the early growth promotion effect of Abundance did not. Our results also demonstrate that selected microbial-based bioproducts, like Abundance, can be compatible with chemical fertilizers to enhance fertilizer use-efficiency and crop yields, but cannot be used as complete substitutes for chemical fertilizers.

수박의 착과절위가 종자 발아 및 유묘활력에 미치는 영향

This study was conducted to investigate the effects of fruit set internode on the germination of watermelon seeds. Generally fruits setted in higher than 20 internode were high percent of germination, fruit setted in low internode(5-10) is low. The higher fruit-set internode, fruit weight was significantly increased, but 1,000 seed weight was decreased the more fruit set internode. However number of seed was about 300 seeds irrespective of fruit-set internode. Investigating viability of seed by BP test, general percent germination was recorded highest at 5 flower cluster above 20 internode of fruit-set internode. In contrast, condition of fruit setted on 3, 4, 6 flower cluster were high percent of germination, regarded as unnormal germination not to be as normal seedling by 2~3%. Seed harvested at 5 flower-cluster had high viability on hypocotyl height and diameter of seedling through early growth test, but were not significant. Therefore 5 flower-cluster was optimum fruit-set internode to obtain high-quality seed.