Propagation of smooth cordgrass,Spartina alterniflora, from seed in North Carolina

Spartina alterniflora-derived porous carbon using as anode material for sodium-ion battery

互花米草入侵对鸟类的生态影响

Efficient adsorption of antibiotics in aqueous solution through ZnCl2-activated biochar derived from Spartina alterniflora

Simple SummaryThe objective of this comprehensive review is to address some important aspects linked to the spread of Spartina alterniflora in China’s coastal wetlands. Firstly, we summarize the mechanisms behind its spread and its ability to adapt to different niches, highlighting its characteristics and strong adaptability. Next, we examine the ecological effects of Spartina alterniflora on various aspects of ecosystem function, including habitat conversion, biodiversity alteration, soil carbon flux and sequestration. The presence of Spartina alterniflora in China has significantly changed the structure and configuration of coastal wetlands. To efficiently manage, increase, or eradicate Spartina alterniflora, it is vital to implement a complete and adaptive plan that reflects the long-term suggestions and precise circumstances within different provinces of China.Invasive plants, like Spartina alterniflora (SA), have a competitive advantage over native flora due to their rapid utilization of vital soil nutrients. This results in the depletion of resources for native plant species, significantly impacting ecosystem diversity and stability. This comprehensive review addresses several key aspects related to SA’s spread and spatial distribution in China’s wetlands. The rapid expansion of Spartina alterniflora is attributed to its high reproductive ability, adaptability to environmental factors like elevated salinity, and ability to disperse its seeds via tides. Spartina alterniflora mainly were found in Zhejiang, Jiangsu, Fujian, and Shanghai provinces, accounting for more than 90% of China’s total Spartina alterniflora area. Spartina alterniflora rapid growth results in displacement of native species and loss of vital microbial, plant, and animal diversity. Some studies reported that Spartina alterniflora increases carbon storage, while others argue that it weakens this function. The impact of Spartina alterniflora on organic and inorganic carbon requires further research for better understanding dynamics of carbon in coastal wetlands. The controlled growth of Spartina alterniflora can be beneficial in many aspects of the coastal wetlands’ ecosystem. In China, various methods have been employed to control the invasion of SA. Physical control, such as removing the plants and converting them into fertilizer or bioenergy, has been commonly used but has limitations like air pollution and the potential for re-invasion. Chemical herbicides like Imazapyr and Haloxyfop-R-methyl have effectively controlled and prevented re-invasion in specific areas, but their potential adverse impacts are still uncertain. Wetland Park construction, aquaculture development, and substituting native or exotic species with mangroves or reed communities have also been successful. It becomes evident that a long-standing and Contextual approach is necessary to effectively manage the advantages and curtail the drawbacks associated with S. alterniflora across China.

Spartina alterniflora is one of the most noxious invasive plants in China and many other regions. Exploring environmentally friendly, economic and effective techniques for controlling Spartina alterniflora is of great significance for the management of coastal wetlands. In the present study, different approaches, including mowing and waterlogging, mowing and tilling and herbicide application, were used to control Spartina alterniflora. The results suggest that the integrated approach of mowing and waterlogging could eradicate Spartina alterniflora, the herbicide haloxyfop-r-methyl could kill almost all the Spartina alterniflora, and the integrated approach of mowing and tilling at the end of the growing season was a perfect way to inhibit the germination of Spartina alterniflora in the following year. However, no matter which control approach is adopted, secondary invasion of Spartina alterniflora must be avoided. Otherwise, all the efforts will be wasted in a few years.

The study reports the responses of photosynthesis to NaCl stress in two C4 species: a glycophyte Setaria viridis (SV) and a halophyte Spartina alterniflora (SA). SV was unable to survive following exposure to NaCl level higher than 100 mM, in contrast, SA could tolerate NaCl up to 550 mM. Under different O2 concentrations, SV showed an increased P700 oxidation level following NaCl treatment, while SA showed almost no change. We also observed an activation of the NDH-dependent cyclic pathway in SV by about 2.4 times upon exposure to 50 mM NaCl for 12 days; however, its activity in SA dropped by about 25%. Using PTOX inhibitor (n-PG) and inhibitor of the Qo-binding site of Cytb6/f (DBMIB) to restrict electrons flow towards PSI, at either 2% or 21% O2, we showed an enhanced plastid terminal oxidase (PTOX) activity for SA but not for SV under NaCl stress. We further showed that both the mRNA and protein levels of PTOX increased by about 3~4 times for SA under NaCl stress but not or much less for SV. All these suggest that the up-regulation of PTOX is a major mechanism used by halotype C4 species SA to cope with salt stress.

In view of the difficulty and high cost of monitoring the invasion of small aggregations of Spartina alterniflora in coastal wetlands, this study proposes a SA-YOLO detection model. First, by adopting a lightweight cascade attention mechanism as the feature extraction part of the network, the model's ability to extract features from Spartina alterniflora images is optimized. Secondly, the convolution layer with an improved adaptive attention mechanism is added to optimize feature extraction, dynamically adjust the weight of the feature map, and reduce the amount of calculation. Thirdly, the improved adaptive convolution network is used to optimize the original neck layer, improve the model's ability to integrate Spartina alterniflora image features, and reduce the amount of calculation. Finally, a Spartina alterniflora recognition system is independently built. The system effectively implements the proposed method and realizes the detection and recording of Spartina alterniflora information. This study successfully verifies the effectiveness of the proposed method by conducting experiments on the actual collected Spartina alterniflora dataset. The test results show that the recall rate and accuracy of the proposed SA-YOLO Spartina alterniflora detection model are 94.5% and 92.4%, respectively, both reaching a high level. It can be seen that the model can complete the identification and detection tasks of Spartina alterniflora, providing a solution for the identification and information collection of Spartina alterniflora in coastal areas.

Short-term C 4 plant Spartina alterniflora invasions change the soil carbon in C 3 plant-dominated tidal wetlands on a growing estuarine Island

Although it is known that wetland plant species exhibit considerable interspecific variation in salt tolerance across coastal plant communities, very little is known concerning the amount of intraspecific variation in salt tolerance within plant species. Panicum hemitomon, Spartina patens and Spartina alterniflora are dominant emergent macrophytes of fresh, brackish and salt marshes, respectively. To investigate intraspecific variation in salt tolerance, plant material was collected from Gulf Coast populations of each of these species and subjected to a salinity screening protocol. All three of the plant species displayed significant intraspecific variation in lethal salinity level and plant morphology. Lethal salinity levels ranged from 7.67$\\perthous$ to 12.0$\\perthous$ in Panicum hemitomon, from 63$\\perthous$ to 93$\\perthous$ in Spartina patens, and from 83$\\perthous$ to 115$\\perthous$ in Spartina alterniflora. Population morphological differences were most correlated with salt tolerance in Panicum hemitomon, the fresh marsh dominant and least correlated with Spartina alterniflora, the salt marsh dominant. Investigations conducted at sublethal salinity levels on subsets of populations showed that plant photosynthetic response was able to differentiate highly salt-tolerant and poorly salt-tolerant populations within each species to varying degrees. These differences were greatest in Panicum populations, with the highly salt-tolerant populations having higher photosynthetic rates and greater water use efficiencies. Highly salt-tolerant populations of Panicum hemitomon and Spartina patens were able to limit the total cation concentrations in their leaves, maintain greater leaf xylem pressures, and accumulate less proline than poorly salt tolerant populations, but apparently had only limited control over the ionic composition. Conversely, Spartina alterniflora populations showed no differences in leaf total cation concentrations, but the highly salt-tolerant populations were able to selectively decrease their Na:K ratio and accumulate more glycinebetaine than poorly salt-tolerant populations. It is concluded that in Panicum hemitomon plant size factors and photosynthetic rates are important in explaining population differences in salt tolerance by providing more mature tissue for the translocation of salts away from actively growing regions. The importance of plant morphology decreases as physiological/biochemical responses become progressively more important in explaining intraspecific variation in salt tolerance in Spartina patens and Spartina alterniflora.

As a coastal halophyte, Spartina alterniflora has high salt tolerance. However, the mechanism at the molecular level has not been widely studied due to the absence of a reference genome. The proteins of NAC families are plant-specific transcription factors that regulate the growth, development and stress response in plants. To identify the NAC family and explore the relationship between NAC proteins and the growth, development and stress response of Spatina alterniflora, full-length transcriptome data of Spartina alterniflora by the third generation sequencing technology was used as reference sequences in this study to blast with the NAC protein sequences from Oryza sativa, Arabidopsis thaliana and Zea mays. Finally, 62 SaNAC proteins were found in Spartina alterniflora by deep analysis on conserved domains. Then we analyzed sequence alignment, evolution, motif prediction, homology comparison, subcellular localization, tissue and abiotic stress-induced gene differential expression profile on the NAC family members in Spartina alterniflora. As a result, all SaNAC proteins were found containing a conserved NAM domain and having certain evolutionary similarity with rice; two family proteins, SaNAC9 and SaNAC49, were expressed in the nucleus; moreover, SaNAC genes were identified to have distinct expressional profiles in different tissues and stress response of Spartina alterniflora. These results indicated the SaNAC transcription factor family not only had conserved functional domains but also played important role in the regulation of growth, development and abiotic stress response.

Temporal–spatial variation and source analysis of carbon and nitrogen in a tidal wetland of Luoyuan Bay

The central Jiangsu coast is typical of China's coastal muddy silt with an average tidal range of 4 m. The shoreline has been gradually advancing seaward as the coast was supplied by a large amount sediment from ancient Yangtze River and Yellow River. As a result, a lot of land resources are fostered in the coast. Therefore tidal flat reclamation activities gradually intensified to the demand of economic development. A large- scale reclamation plan in Jiangsu coast has been implemented since the 21 st century and Spartina alterniflora marsh has become the main target of tidal flat reclamation. Thus how Spartina alterniflora marsh will expand during the reclamation period is worthy of study. Thirteen phases of satellite imageries from 2001 to 2013 and field observation data are analyzed to quantify the expansion rate of Spartina alterniflora marsh in association with the reclamation activities. The result shows that Spartina alterniflora expansion during 2001- 2013 can be divided into three periods. During 2001- 2007,the Spartina alterniflora area outside the seawall was relatively large and the influence on the tidal flat sedimentary environment by reclamation did not hamper its expansion. As a result,both the annually increased Spartina alterniflora area and the expansion rate keep pace with reclamation. During 2008- 2010, the Spartina alterniflora area outside the seawall decreased significantly; nevertheless, the mean annual expansion rate of the Spartina alterniflora marsh was still relatively high. During 2011- 2013, the area of Spartina alterniflora marsh became small because of the reclamation activities during 2001-2007 and 2008-2010 periods. Spartina alterniflora expansion became stabilized. As such, the pattern of the marsh expansion differs in response to the reclamation rate and stages. If a sufficiently wide marsh can be maintained during reclamation, then the marsh will continue to grow. The underlying mechanism is that the Spartina alterniflora marsh is influenced by the generation of seedling and the sediment types and bed elevation, while reclamation will affect all these factors. The relationship between marsh expansion and reclamation rate for the period of 2001- 2007 indicates that, for sustainable reclamation on the Jiangsu coast, a width of 0.9-1 km for the Spartina alterniflora marsh should be maintained.

Spatio-temporal dynamics of net primary productivity and the economic value of Spartina alterniflora in the coastal regions of China

The present study reveals contrasting responses of photosynthesis to salt stress in two C4 species: a glycophyte Setaria viridis (SV) and a halophyte Spartina alterniflora (SA). Specifically, the effect of short-term salt stress treatment on the photosynthetic CO2 uptake and electron transport were investigated in SV and its salt-tolerant close relative SA. In this experiment, at the beginning, plants were grown in soil then were exposed to salt stress under hydroponic conditions for two weeks. SV demonstrated a much higher susceptibility to salt stress than SA; while, SV was incapable to survive subjected to about 100 mM, SA can tolerate salt concentrations up to 550 mM with slight effect on photosynthetic CO2 uptake rates and electrons transport chain conductance (gETC). Regardless the oxygen concentration used, our results show an enhancement in the P700 oxidation with increasing O2 concentration for SV following NaCl treatment and almost no change for SA. We also observed an activation of the cyclic NDH-dependent pathway in SV by about 2.36 times upon exposure to 50 mM NaCl for 12 days (d); however, its activity in SA drops by about 25% compared to the control without salt treatment. Using PTOX inhibitor (n-PG) and that of the Qo-binding site of Cytb6/f (DBMIB), at two O2 levels (2 and 21%), to restrict electrons flow towards PSI, we successfully revealed the presence of a possible PTOX activity under salt stress for SA but not for SV. However, by q-PCR and western-blot analysis, we showed an increase in PTOX amount by about 3–4 times for SA under salt stress but not or very less for SV. Overall, this study provides strong proof for the existence of PTOX as an alternative electron pathway in C4 species (SA), which might play more than a photoprotective role under salt stress.

The invasion of Spartina alterniflora (SA) has led to significant hydrogen sulfide (H2S) production in coastal wetlands. The phytotoxic S2− plays a critical role in elemental biogeochemistry and may contribute to the successful invasion of SA in areas contaminated with heavy metals. To explore how H2S influences nutrient uptake and energy utilization in SA and the native Phragmites australis (PA) under cadmium (Cd) stress, and to uncover the mechanisms by which H2S facilitates SA invasion, a hydroponic experiment was conducted. This experiment included three Cd concentrations (0, 1 and 2 mg Cd L−1) and three H2S treatments (inhibiting H2S synthesis, simulating an external H2S source and untreated control). Results revealed that H2S plays a crucial role in balancing the uptake of Mg, Mn, Ca and Zn in SA, mitigating Cd-induced damage to the photosynthetic system and enhancing nutrient and energy accumulation under Cd stress. In contrast, H2S was toxic to PA, increasing lipid peroxidation, inhibiting growth, and disrupting mineral uptake, particularly of Ca. This exacerbated the detrimental effects of Cd on the photosynthetic system and nutrient accumulation in PA. These results highlight that irrespective of Cd treatment, H2S enhanced energy accumulation, mineral uptake, and growth in SA compared to PA, which could support the ecological niche competition within the coastal wetlands during the invasion of SA into PA habitats. Consequently, inhibiting endogenous H2S synthesis in SA may offer a potential strategy for controlling its invasion.