Growth and Nutritional Responses of Cowpea (cv. Soronko) to Short-term Elevated Temperature

Abstract

Short-term variations in temperature associated with climate change have been noted to affect the physiological processes and metabolite profile of plants, including the nutritional status, ultimately affecting their growth and development. An evaluation of the effects of elevated temperatures on the growth and nutritional quality of cowpea was performed during this experiment. The main objective was to evaluate the effects of short-term elevated temperatures on the nutritional quality of cowpea at different growth stages. Surface-sterilized seeds of cowpea (cv. Soronko) were germinated in pots in the glasshouse. At different growth stages (preflowering, flowering, and postflowering), plants were incubated in growth chambers set at three different temperature regimes (25, 30, and 35 °C) for a period of 7 days. Compared with control (25 °C), exposure to both elevated temperatures (30 and 35 °C) reduced the whole plant fresh weight and dry weight by 30% and 52% and 42% and 29%, respectively, at the preflowering stage, and by 31 and 60% and 47 and 63%, respectively, at the flowering/anthesis stage. However, no significant difference in whole plant biomass was noted between elevated temperatures (35%) and the control temperature at the postflowering stage. Short-term exposure to an elevated temperature (35 °C) increased the shoot crude protein content (5.59 N%) of cowpea compared with control (3.77 N%) and preflowering stage. In contrast, at the flowering stage, an elevated temperature (35 °C) reduced the crude protein content (1.77%) of the shoot compared with control (5.59%). At an elevated temperature (35 °C), the preflowering and flowering stages of cowpea were most affected compared with control. These results suggest that the preflowering and flowering stages of cowpea compared with the postflowering stage are more susceptible to elevated temperatures (30 to 35 °C).