Physiological and Biochemical Responses of Invasive Species Cenchrus pauciflorus Benth to Drought Stress

The invasive plant Cenchrus pauciflorus Benth exhibits strong adaptability to stress, especially drought. When newly introduced certain plant species can become invasive and quickly spread in an area due to lack of competition, potentially disturbing the ecological balance and species diversity. C. pauciflorus has been known to cause huge economic losses to agriculture and animal husbandry. Thus, understanding the physiological responses of C. pauciflorus to drought stress could help explore the role of C. pauciflorus in population expansion in sandy land environments. In this study, we evaluated the response of C. pauciflorus to induced low, moderate, and severe drought stress conditions. Results showed a linear reduction in the fresh weight (FW), dry weight (DW), and relative water content (RWC) of the aboveground parts of C. pauciflorus following drought stress as compared to the control plants (no drought stress). Chemical analyses showed that the drought treatments significantly induced the production of proline, soluble proteins, soluble sugars, MDA, and free amino acids as compared to the control treatment (no drought stress). On the other hand, the starch content was significantly reduced in drought-treated plants. This was also accompanied by a significant linear increase in the antioxidant enzyme activities (SOD, POD, and CAT) in plants subjected to drought stress. On the basis of physiological and biochemical analyses, we propose that C. pauciflorus has evolved to survive harsh drought stress conditions of the desert via sophisticated biochemical adjustment and antioxidant reprograming that allows protection against damage caused by drought stress.