Advantages of growth and competitive ability of the invasive plant Solanum rostratum over two co-occurring natives and the effects of nitrogen levels and forms

Higher Nitrogen Uptakes Contribute to Growth Advantage of Invasive Solanum rostratum over Two Co-Occurring Natives Under Different Soil Nitrogen Forms and Concentrations

High nitrogen (N) uptake is one of the main reasons for invasive alien plant invasions. However, little effort has been made to compare the effects of different N forms on N uptake between invasive and native plants, especially those on N form acquisition strategies (preference and plasticity), which influence N uptake, and thus exotic plant invasions. Related studies are particularly few in barren habitats, where the effects of N deposition on invasiveness are considered to be much weaker than in fertile habitats. In this study, we grew Solanum rostratum, a noxious invader in barren habitats, and the native plants Leymus chinensis and Agropyron cristatum in both mono- and mixed cultures under nitrate and ammonium addition treatments, and analyzed the effects of the soil N availability and forms on the growth, N uptake, and N form acquisition strategies for these plants. The invader outperformed the natives in N uptake (in most cases) and growth (always) in both mono- and mixed cultures under all N treatments. N addition increased the N uptake and growth of the invader. The advantages of the invader over the natives were higher under ammonium relative to nitrate addition. The growth advantage of the invader was associated with its higher N uptake and higher N-use efficiency. Higher plasticity in N form uptake may contribute to the higher N uptake for the invader when grown in mixed cultures. Our findings indicate that N deposition, particularly in the form of ammonium, may accelerate exotic plant invasions in barren habitats.

Adaptive Benefits of Antioxidant and Hormone Fluctuations in Wedelia trilobata Under Simulated Salt Stress with Nutrient Conditions

Salinity is one of the most significant environmental factors limiting plant development and productivity. Invasive plants could quickly respond to environmental changes, thus successfully achieving invasion. However, there is limited research on the mechanism of salt responses in invasive plants under different nutritional conditions. This study evaluated and compared the impact of salinity stress and nutrient application on physiological responses in the invasive plant Wedelia trilobata and native plant Wedelia chinensis. Mild salinity stress disrupted the growth of these two plants, significantly reducing their leaf and stem node number under a low nutrient condition. W. trilobata showed notable decreases in height and leaf number with high salinity stress regardless of nutrient levels, whereas it was observed only in the low nutrient state in W. chinensis. The negative effects of high salinity on both species were most evident in nutrient-poor environments. Under low salinity and nutrient stress, W. trilobata's leaves exhibited increased levels of proline, MDA, CAT, and ABA, with decreased GA and IAA content. A low-salt environment favored W. trilobata's competitive advantage, and nutrient enrichment appeared to enhance its invasive potential, in which process the plant antioxidant system and endogenous hormones contribute greatly. This study provides a theoretical foundation for predicting suitable growth areas for W. trilobata referring to the salt condition, guiding future strategies for preventing and controlling its invasive spread.

Buffalo-bur (Solanum rostratum Dunal) invasiveness, bioactivities, and utilization: a review

Solanum rostratum Dunal, belongs to the Solanaceae family and has drawn attention for its intricate interplay of invasiveness, phytochemical composition, and potential bioactivities. Notably invasive, S. rostratum employs adaptive mechanisms during senescence, featuring thorn formation on leaves, fruits, and stems seed self-propulsion, and resistance to drought. This adaptability has led to its proliferation in countries such as China, Canada, and Australia, extending beyond its Mexican origin. Despite its invasive historical reputation, recent studies unveil a rich array of phytochemicals in S. rostratum, suggesting untapped economic potential due to under-exploration. This review delves into exploring the potential uses of S. rostratum while elucidating the bioactive compounds associated with diverse identified bioactivities. In terms of phytochemistry, S. rostratum reveals an abundance of various bioactive compounds, including alkaloids, flavonoids, phenols, saponins, and glycosides. These compounds confer a range of beneficial bioactivities, encompassing antioxidant, antifungal, anticarcinogenic, anti-inflammatory, phytotoxic, and pesticidal properties. This positions S. rostratum as a reservoir of valuable chemical constituents with potential applications, particularly in medicine and agriculture. The review provides comprehensive insights into the phytochemistry, bioactivities, and bioactivity-guided fractionation of S. rostratum. In this review, we focus on the potential utilization of S. rostratum by emphasizing its phytochemical profile, which holds promise for diverse applications. This review is the first that advocates for further exploration and research to unlock the plant's full potential for both economic and environmental benefit.