Cadmium toxicity in African yam bean (Sphenostylis stenocarpa (HOCHST. EX A.RICH.) HARMS genotypes

Abstract

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.

African yam beans (Sphenostylis stenocarpa): A review of a novel tropical food plant for human nutrition, health and food security

“…It was reported that the tubers can be cooked and eaten in the same manner with other tubers like yams and potatoes. The flavor of the tuber is similar to that of potatoes (Olisa et al, 2010;Okoye et al, 2019). The colour of the seed may differ from creamywhite or brownish-yellow to dark brown, occasionally with black steaky appearance.…”

“…Ikemefuna and Julian, 2010). AYB plant yields small spindle-figured tubers that are about 5.0 to 7.5 cm tall (Olisa et al, 2010;Okoye et al, 2019;Aremu and Ibirinde, 2012). The seeds are usually ground and substituted to other flour to produce composite flour so as to improve its functional potentials.…”

“…The tubers could be eaten raw or processed, however, the details are still not well understood, therefore, more work is expected to be carried out on this. Some countries like Mexico process the raw AYB in the following ways: raw tubers are sliced into sticks, sprinkled with lime juice and chill; the sliced tuber could be added to salads for dinner; cooked tuber could be used with or without vegetables for soup preparation; they can also be grated and boiled in milk to create a tasty drink; the tuber could be sliced, diced and pickled with onion and chill to form a popular snack food (Heuze, 2016;Ojueoderie and Balogun, 2019;Okoye et al, 2019).…”

Introduction to Africa Yam Bean (Sphenostylis Stenocarpa (Hochst. Ex A. Rich.) Harms)

“…The crop tubers can be roasted, fried, or cooked and eaten such as yam and potato. The tuber flavor is like that of potatoes [62]. The tubers from Africa yam bean can be store for a longer period without any form of spoilage due to microbial action as a result of its low moisture content of about 10.3% [44].…”