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Crude oil pollution is one of the commonest environmental pollution plaguing the Niger Delta in Nigeria due to transportation, accidental discharge and spillage. This study aimed to ascertain the changes in physicochemical properties and heavy metals level of crude oil polluted soil propagated using randomized block design and measured by standard methods. The physicochemical properties of the soil before and after the end of the experiment were 0.89% (MC), 0.30% (N). 96.25ppm (P), 1.33meq/mg (K) and 1.62% (OC) as compared to 0.16% (MC), 0.27% (N), 6.00 ppm (P), 0.72 meq/mg (K) and 1.84% (OC) in control. The soil was maintained its alkaline status of 6.00-6.50. There was an increase in Cu, Fe and Mn in HI from 3.33 to 3.44 and 3.42 ppm, 108.99 to 138.67 and 139.05 ppm, and 147.21 to 169.97 and 170.23 ppm respectively. However, there was an increase in Zn and Pb content of HI from 94.44 to 73.93 and 74.02 ppm, and 42.10 to 27.80 and 25.45 ppm respectively of the C. annum and C. frutescens. In conclusion, crude oil affects soil properties irrespective of season by precipitating a hydrophobic layer thus creating a competitive interaction between heavy metals and essential nutrients.

Cadmium toxicity in African yam bean (Sphenostylis stenocarpa) (Hochst. ex A.Rich.) Harms genotypesAbstract: The aim of the study was to investigate the growth responses of African yam bean (Sphenostylis sternocarpa (Hochst. ex A. Rich.) Harms (AYB) to cadmium pollution. Top garden soil (0 -10 cm) was obtained as pooled and polluted with cadmium (as CdCl 2 ) at the rate of 12 mg kg -1 , which is equivalent to 3 times the ecotoxicological screening value of Cd. The polluted soils were made ready for use 3 days later. Nine selected AYB accessions (TSs-87, TSs-89, TSs-90, TSs-91, TSs-92, TSs-93, TSs-94, TSs-95, and TSs-96) were pre-soaked for 30 minutes and then sown in the polluted and unpolluted soils. Data collected were subjected to ANOVA, and means were separated at 95 % confidence interval. Results showed that incidence of cadmium pollution significantly delayed seedling emergence in all tested AYB accessions by at least one day (p < 0.05). Despite exposure to Cd, TSs-96 attained 50 % emergence faster than other accessions. Although there were general reductions in yield due to exposure to Cd, TSs-92 showed the least percentage yield reduction (50 %), compared to 74 % yield reduction in TSs-93, thereby suggesting a comparatively better yield capacity compared to the other test accessions. Overall, decrease in total chlorophyll content seems to be the major reason of injury in Cd-exposed plants. Toksičnost kadmija za izbrane genotipe afriškega gomoljastega fižola(Sphenostylis stenocarpa) (Hochst. ex A.Rich.) HarmsIzvleček: Namen raziskave je bil preučiti rastni odziv afriškega gomoljastega fižola (Sphenostylis sternocarpa (Hochst. ex A. Rich.) Harms (AYB) na onesnaženje tal s kadmijem. Vzorčena je bila vrhnja plast vrtnih tal (0 -10 cm), onesnažena s kadmijem (kot CdCl 2 ) v velikosti 12 mg kg -1 , kar je trikratni ekvivalent priporočene ekotoksikološke vrednosti za Cd. Onesnažena tla so bila pripravljena za poskus v treh dneh. Izbranih je bilo devet akcesij AYB (TSs-87, TSs-89, TSs-90, TSs-91, TSs-92, TSs-93, TSs-94, TSs-95, in TSs-96), katerih semena so bila predhodno namočena za 30 minut in potem posejana v onesnažena in neonesnaženea tla. Zbrani podatki so bili ovrednoteni z ANOVA, kjer so bila poprečja ločena pri 95 % intervalu zaupanja. Rezultati so pokazali, da je onesnaženje s kadmijem značilno zamaknilo vznik kalic AYB pri vseh preiskušenih akcesijah najmanj za en dan (p < 0,05). Kljub izpostavitvi Cd, je akcesija TSs-96 dosegla 50 % kalivost hitreje kot vse ostale. Kljub splošnemu upadu pridelka zaradi izpostavljenosti kadmiju, je akcesija TSs-92 pokazala najmanjši upad pridelka (50 %), v primerjavi s 74 % upadom pri akcesiji TSs-93, kar kaže na njeno boljšo primerjalno sposobnost prilagoditve v primerjavi z drugimi genotipi. Na splošno je bil glavni razlog poškodb zaradi Cd pri vseh izpostavljenih rastlinah upad celokupne vsebnosti klorofila.

In Nigeria, S. stenocarpa is an under-utilized leguminous crop grown in Edo State mainly for its tuberous root and less for the seeds. The purpose of this study was to determine the nitrogen assimilation and distribution pattern of S. stenocarpa exposed to cadmium stress by partitioning the plant accessions into root and leaf, and N-nitrate and N-ammonia analysis was carried out during the seedling and flowering stage. The results showed that cadmium stress increased percentage foliar total nitrogen in TSs-91 in the Cd-5ESV from 2.03% to 2.03% and 1.93% to 5.73% 6 and 18 weeks after sowing with increased cadmium concentration. However, there was a reduction in leaves Nitrate-N with increase in cadmium concentration. TSs-93 in Cd-5ESV had a Nitrate-N of 703.84 ppm as compared to 968.14 ppm in control while the root was significantly reduced from 771.71 to 516.36 ppm. Irrespective of leaves, roots and metal concentration, TSs-91 sow in control soils assimilated 6.29% nitrogen nitrate as compared to 0.16% in nitrogen ammonia. It was observed that the plants assimilated nitrogen more in the nitrate form than in the ammonia form and are stored in the leaves as compared to the roots except TSs-95 which stored more N-nitrate in the roots.

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