Root Responses to Aluminum Stress in Cowpea (Vigna unguiculata L.)

David Hickok, Tennessee State University


Cowpea is a crop that is widely grown in areas that are having issues with food scarcity, such as sub – Saharan Africa, Southern Asia, South America, and in the Southeastern United States. This makes research on cowpea improvement a likely way to supply the increased demand for food products in these areas. Aluminum toxicity is one of the most important abiotic stresses limiting cowpea production in the world, resulting in poor root growth and changes in root morphology leading to less efficient water and nutrient uptake. Identification of cultivars with aluminum toxicity stress tolerance should be a main objective of cowpea improvement programs in the Southeastern USA where aluminum toxic soils are common. Two hydroponics experiments were carried out to administer aluminum to cowpea plants and determine the effects of toxicity on cowpea root systems. Each hydroponic experiment used the same nutrient solution for control and added 50µM of AlCl3 for treatment. Additionally, two cowpea genotypes (Dixie Lee and Queen Anne) were identified as being suitable for germination in growth chamber transfer to hydroponics solution. Seeds were germinated on petri dishes on autoclaved paper towels prior to transfer to hydroponics tanks. WinRhizo was used to analyze root characteristics over a range of days (8 days in experiment 1 and 5 days in experiment 2). Eight root growth characteristics were looked at to determine root responses to aluminum: root volume (VOL), root surface area (SA), number of crosses (NCROS), number of forks (NFORKS), root length (LEN), average root diameter (AVGD), and projected root area (PA). It was found that response differed between the two experiments. The first experiment resulted in root thickening in cowpea grown in the aluminum hydroponic solution, a result consistent with other plants. The second experiment found that root growth was not inhibited in the aluminum hydroponics solution. RNA was then extracted from lateral roots and analyzed for quality and quantity to later be used in RNA-seq for aluminum stress resistance candidate genes. The results from the two experiments can be used to guide further research and analysis of cowpea responses to aluminum in hydroponic solution.

Subject Area

Plant sciences

Recommended Citation

David Hickok, "Root Responses to Aluminum Stress in Cowpea (Vigna unguiculata L.)" (2021). ETD Collection for Tennessee State University. Paper AAI28721125.