Adaptive photosynthetic strategies of the invasive plant Sphagneticola trilobata and its hybrid to a low-light environment

Abstract

In stressful environments, invasive plants acclimate more efficiently than native plants and hybridization mainly contributes to this process. We examined changes in the morphological characteristics, photosynthetic characteristics, and antioxidant capacity of Sphagneticola trilobata and its hybrids in a low-light environment to explore their invasiveness, with Sphagneticola calendulacea serving as the control. The morphological plasticity of S. trilobata was not dominant, the maximal photochemical efficiency of PSII, actual quantum yield of PSII, and electron transport rate of PSⅡ increased and nonphotochemical quenching decreased, while S. calendulacea and the hybrid produced opposite results. S. trilobata showed fewer spots stained for reactive oxygen species in tissues, with an increase in superoxide dismutase activity. Although S. trilobata is a heliophilous plant, we found that the shade tolerance of S. trilobata and the hybrid were stronger than that of S. calendulacea, which may be one important mechanism of invasion. Highlights• Shading promoted the plant height but decreased the stem length of Sphagneticola trilobata • S. calendulacea has the strong photosynthetic capacity and antioxidant activity in the shade • Shade tolerance of the hybrid is more efficient than that of S. calendulacea

Strong Invasive Mechanism of Wedelia trilobata via Growth and Physiological Traits under Nitrogen Stress Condition

“…Similarly, the Fv/Fm value was greater than W. chinensis under low-N conditions. Similar results were also reported by Ke et al [35]. W. trilobata have stronger net fluorescence Fv/Fm than W. chinensis under low-light conditions, demonstrating that low-light conditions accelerate the photosystem II reaction that converts light energy to heat energy.…”

“…The photosynthetic and physiological response of W. trilobata was significantly higher under low-temperature and -light conditions [30]. Previous studies observed that W. trilobata has a strong response to N enrichment and flooding conditions and better antioxidant enzyme activities under different forms of nitrogen compared with native Wedelia [34,35]. Until now, there has been no specific information on the physiological and biochemical application of W. trilobata under N deficit conditions.…”

“…The full leaves of W. trilobata and W. chinensis with control and treatment were immersed in diaminobenzidine (DAB) solution containing 0.5 mg/mL −1 with pH 8.0. Phosphate buffer was used as the solvent for 15 min before being covered with gauze and kept in the dark for 7 h. The accumulation of ROS could be seen as brown dots after DAB staining [35]. Similarly, both plant species were immersed in a solution using 0.1% nitro-blue tetrazolium (NBT) and 10 mM sodium azide using pH 6.4 phosphate buffer as the solvent.…”