Comparison of the Ability to Control Water Loss in the Detached Leaves of Wedelia trilobata, Wedelia chinensis, and Their Hybrid

Abstract

In the process of biological invasion, hybridization between invasive species and native species is very common, which may lead to the formation of hybrids with a stronger adaptability. The hybrid of Wedelia trilobata (an alien invasive species) and Wedelia chinensis (an indigenous congener) has been found in South China. In our previous study, we found that the hybrid showed heterosis under cadmium stress. However, the results of this experiment demonstrated that the leaves of the hybrid had no heterosis in controlling water loss. The results showed that the water loss rate of W. trilobata was the slowest, that of W. chinensis was the fastest, and that of the hybrid was in the middle. Compared with W. chinensis and the hybrid, W. trilobata accumulated more abscisic acid (ABA) in leaves to control water loss. After the leaves were detached, W. chinensis leaves suffered the most serious damage, the lowest maximum photochemical efficiency, the most serious membrane lipid peroxidation, and the largest accumulation of malondialdehyde and reactive oxygen species. Compared with W. chinensis and its hybrid, the leaves of W. trilobata could accumulate more antioxidant enzymes and antioxidants, and the total antioxidant capacity was the strongest. The results demonstrate that the ability of the hybrid to reduce water loss was lower than that of W. trilobata, but higher than that of W. chinensis. They showed that the drought resistance of the hybrid may be higher than that of W. chinensis, and it might threaten the survival of W. chinensis.

Adaptation of the Invasive Plant (Sphagneticola trilobata L. Pruski) to a High Cadmium Environment by Hybridizing With Native Relatives

“…In the natural environment, studies have reported that there are hybrid species, of these two species, S. trilobata is paternal and S. calendulacea is maternal ( Wu et al, 2013 ; Li et al, 2015 ). In our previous research, we found that the tolerance of hybrid to water stress was in the middle of parents ( Zhang et al, 2020a ). For S. trilobata , the adaptability to water stress of hybrid enlarged the invasion and propagation of the genes of S. trilobata in the invasive region.…”

“…But the habitats of these two species are different. Our previous study has identified that S. trilobata is more resistant to water than S. calendulacea ( Zhang et al, 2020a ). In the natural environment, studies have reported that there are hybrid species, of these two species, S. trilobata is paternal and S. calendulacea is maternal ( Wu et al, 2013 ; Li et al, 2015 ).…”

“…For S. trilobata , the adaptability to water stress of hybrid enlarged the invasion and propagation of the genes of S. trilobata in the invasive region. Therefore, we believe that, in addition to the water factor, the hybrid may have wider adaptability to other environmental factors than the S. trilobata , because the hybrid combines some genotypes from parents and thus shows hybridization advantages ( Zhang et al, 2020a ).…”

“…We select the heavy metal Cadmium (Cd) as the environmental factor and try to study the tolerance of S. trilobata and its hybrid to Cd ion concentration in soil. The increase of Cd in the soil is related to human interference with the natural environment, and this aspect has become an important indicator of soil and water environmental pollution ( Zhang et al, 2020a ). The study has found that S. trilobata is the dominant species in the wasteland of Cd-rich lead–zinc mining areas in Guangdong, China ( Xiao et al, 2021 ).…”

“…S. trilobata mainly grows near marshes or damp places such as banks of the river, and these places are often the most serious places of human disturbance ( Cai et al, 2020 ; Sun et al, 2020 ; Zhang et al, 2020a ). Because of pollution and waste emissions, soil Cd ions are often very high.…”