Evaluation of biochemical, photosynthetic and physiological characteristics of cowpea (Vigna unguiculata l. Walp) accessions to cadmium stress
August 9, 2019
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| Article Title: | Evaluation of biochemical, photosynthetic and physiological characteristics of cowpea (Vigna unguiculata l. Walp) accessions to cadmium stress |
| Authors: | Ohanmu E., O., Ikhajiagbe B., Anoliefo G., O. |
| Affiliation: | 1Department of Plant Biology and Biotechnology, Faculty of Science, Edo University, Iyamho, Nigeria 2Environmental Biotechnology and Sustainability Research Group, Department of Plant Biology and Biotechnology, University of Benin, Benin City, Nigeria |
| Abstract: | Cadmium stress are known to reduce crop productivity, increase reactive oxygen species and impair photosynthetic processes. The present study aimed to determine the physiological and biochemical characters of cowpea accessions (TVu-91, TVu-92, TVu-93, TVu-95, and TVu-96) to cadmium stress. Cowpea seeds were exposed to three concentration of CdCl2; the control (0ESV), Cd-2.5ESV and Cd-5ESV and laid out in randomized block design (RBD) for five months. Parameters were evaluated both above and below ground level at the seedling stage. The leaves were partitioned into young leaf (YP), intermediate leaf (IP) and old leaf (OP) for a concise distribution of foliar chlorosis and necrosis 84 days after sowing. The physiological characters, chlorophyll content, enzymatic and non-enzymatic activities were also determined. From the result, the shoot, root and petiole length, number of primary stem and root branches of TVu-91, TVu-92, TVu-93, TVu-95 and TVu-96 were reduced with increased cadmium concentration. Cadmium stress also resulted to a significant difference in the number of root nodule of TVu-96 as compared to TVu-95. Cadmium stress increased foliar chlorosis and necrosis with increased concentration however, the effect were more in older leaves (OP) as compared to the young leaves (YP) and intermediate leaves (IP). There was an insignificant increase in the chlorophyll-a/b content with increased concentration. Superoxide dismutase (SOD) and catalase (CAT) showed the highest activities in TVu-93 while the MDA content of TVu-92 and TVu-93 were significantly increased. Generally, cadmium stress reduced the overall foliar yield, plant dry weight and root dry weight of cowpea accessions. Cadmium significantly reduced the above and below shoot parameters, resulting in increased MDA levels however, the plant responded by employing proline and catalase as a defense mechanism in combating the oxidative stress mitigated by the metal. |
| Keywords: | proline, mda, cowpea, crop productivity, chlorosis, necrosis |
| *Correspondence: | Edokpolor Osazee Ohanmu, Department of Biological Sciences, Faculty of Science, Edo University Iyamho, Edo State, Nigeria, Tel. +2347084059346, email: edos.ricky@yahoo.com |
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