Adaptation of the Invasive Plant Sphagneticola trilobata (L.) Pruski to Drought Stress

Invasive species and their hybrids with native species threaten biodiversity. However, there are few reports on the drought stress adaptability of invasive species (L.) Pruski and its hybrid with native species . In this study, relative water content (RWC), abscisic acid (ABA), reactive oxygen species, antioxidant capacity, and photosynthetic capacity were measured in the hybrid and its parents under drought stress (13% PEG-6000). Under drought stress, the ABA content and RWC in were the highest. RWC decreased by 28% in , 41% in , and 33% in the hybrid. Activities of the antioxidant enzymes in were the highest, and the accumulation of malondialdehyde (MDA) was the lowest (4.3 μg g ), while it was the highest in (6.9 μg g ). The maximum photochemical efficiency (F /F ) of was the lowest (0.71), and it was the highest in (7.5) at 8 h under drought stress. The results suggest that the drought resistance of the hybrid was weaker than that of but stronger than that of . Therefore, the survival of may be threatened by both the invasive species and the hybrid.