Calligonum polygonoides L. Shrubs Provide Species-Specific Facilitation for the Understory Plants in Coastal Ecosystem

Mycorrhizal Symbiosis Can Change the Composition of Secondary Metabolites in Fruits of Solanum nigrum L

Solanum nigrum is a common weed in arable land, while being used in traditional medicine around the world due to its remarkable levels of valuable secondary metabolites. Agronomic and biological techniques can alter the production of a specific metabolite by influencing plant growth and metabolism. The effects of colonization with three arbuscular mycorrhizal fungi (AMF), including Funneliformis mosseae, Rhizoglomus intraradices, and Rhizoglomus fasciculatum, on the chemical composition of S. nigrum fruits were evaluated by gas chromatography-mass spectrometry (GC-MS) analysis. More than 100 different chemical constituents were evaluated by GC-MS. Our study revealed that the levels of phenols (quinic acid), benzenes (hydroquinone), sulfur-containing compounds, lactone and carboxylic acids were improved by R. intraradices. In contrast, hydroxymethylfurfural increased by 68 % in R. fasciculatum inoculated with uninoculated S. nigrum plants, and this species was also the most efficient in inducing sugar compounds (D-galactose, lactose, and melezitose). Our results suggest that AMF colonization is an effective biological strategy that can alter the chemical composition and improve the medicinal properties of S. nigrum.

Contrasting influences of two dominant plants, Dasiphora fruticosa and Ligularia virguarea, on aboveground and belowground communities in an alpine meadow

Soil organisms are abundant, phylogenetically and functionally diverse, and interact to catalyse and regulate critical soil processes. Understanding what structures belowground communities is therefore fundamental to gaining insight into ecosystem functioning. Dominant plants have been shown to influence belowground communities both directly and indirectly through changes in abiotic and biotic factors. In a field study, we used piecewise structural equation modelling to disentangle and compare the effects of a dominant allelopathic plant, Ligularia virgaurea, and a dominant facilitative plant, Dasiphora fruticosa, on understory plant, soil microbial and nematode community composition in an alpine meadow on the Tibetan plateau. Dasiphora fruticosa was associated with changes in edaphic variables (total nitrogen, soil organic carbon, pH and ammonium), understory plant and soil bacterial communities, whereas Ligularia virguarea was associated with increased soil ammonium content and soil fungal richness relative to dominant plant-free control plots. Moreover, nematode richness was significantly greater under D. fruticosa, with no change in nematode community composition. By contrast, nematode richness under Ligularia virgaurea was similar to that of dominant plant-free control plots, but nematode community composition differed from the control. The effects of both plants were predominantly direct rather than mediated by indirect pathways despite the observed effects on understory plant communities, soil properties and microbial assemblages. Our results highlight the importance of plants in determining soil communities and provide new insight to disentangle the complex above- and belowground linkages.

Addressing artifacts of colorimetric anticancer assays for plant-based drug development

Cancer has become the silent killer in less-developed countries and the most significant cause of morbidity worldwide. The accessible and frequently used treatments include surgery, radiotherapy, chemotherapy, and immunotherapy. Chemotherapeutic drugs traditionally involve using plant-based medications either in the form of isolated compounds or as scaffolds for synthetic drugs. To launch a drug in the market, it has to pass through several intricate steps. The multidrug resistance in cancers calls for novel drug discovery and development. Every year anticancer potential of several plant-based compounds and extracts is reported but only a few advances to clinical trials. The false-positive or negative results impact the progress of the cell-based anticancer assays. There are several cell-based assays but the widely used include MTT, MTS, and XTT. In this article, we have discussed various pitfalls and workable solutions.

Proximate Composition, Bioactive Compounds, and Antioxidant Potential of Wild Halophytes Grown in Coastal Salt Marsh Habitats

Halophytes have been characterized as a potential resource for fiber, food, fodder, and bioactive compounds. Proximate composition, bioactive compounds, and antioxidant activity of five wild dominant halophytes (Arthrocnemummacrostachyum, Halocnemumstrobilaceum, Limoniastrummonopetalum, Limoniastrumpruinosum, and Tamarix nilotica) naturally growing along the Nile Delta coast were assessed. The soil supporting these halophytes was sandy to sand-silty, alkaline, with low organic carbon, and relatively high CaCO3. H. strobilaceum attained the highest moisture content, ash, crude fiber, lipids, and total soluble sugars. L. monopetalum showed the highest content of crude protein (18.00%), while T. nilotica had the highest content of total carbohydrates. The studied halophytes can be ranked according to their nutritive value as follows: H.strobilaceum > L.monopetalum > A.macrostachyum > L.pruinosum > T. nilotica. A. macrostachyum attained the highest amount of Na+, K+, Ca2+, and Mg2+. A. macrostachyum showed a high content of phenolic compounds, while H.strobilaceum was rich in tannins and saponin contents. The MeOH extract of A. macrostachyum and H. strobilaceum exhibited substantial antioxidant activity. The present results showed that the studied halophytes could be considered as candidates for forage production or used as green eco-friendly natural resources for bioactive compounds.

Influence of the invasive shrub Nicotiana glauca Graham on the plant seed bank in various locations in Taif region, western of Saudi Arabia

Invasive species have been considered as one of the most serious threats to the biodiversity of various ecosystems, particularly in arid regions. The present study aimed to assess the influence of the invasive shrub Nicotiana glauca on the biodiversity of different habitats in Taif region, Saudi Arabia as well as to determine the highest habitat with seed bank of N. glauca. Soil samples were collected from three locations (Alwaht, Ash-shafa, and Ar Ruddaf), invaded with N. glauca, and analyzed for the soil seed bank. A soil seed experiment was designed in a greenhouse, whereby emerged plant seedlings were left to grow for three months and identified as well as the species density and biodiversity were assessed under and outside the canopy of N. glauca. Also, the floristic composition, life forms, and chorotype spectra of the plant species of the seed bank were analyzed. A total of 42 species, belonging to 23 families, were recorded in the soil seed bank. Asteraceae, Poaceae, and Cyperaceae were the major families (42.9%). The life form spectra of the recorded species were dominated by Therophytes (59.5%). Chorotype spectra analysis revealed that Mediterranean, Saharo-Arabian, and Irano-Turanian were the most represented elements. The species richness and evenness were higher outside the canopy, which indicates a negative effect of the invasive shrub N. glauca on the plant biodiversity in the study area, particularly in Ar Ruddaf location. This could be attributed to the competition or allelopathic effect of N. glauca. In contrast, the density of N. glauca seeds was higher under the canopy compared to outside. The soil nutrients and moisture under the canopy were higher than outside canopy. The present study provides a deeper understanding of the most susceptible habitats or communities to the invasion by N. glauca and thereby open the challenge toward control of this noxious plant and vegetation restoration.

Functional Traits Plasticity of the Invasive Herb Argemone ochroleuca Sweet in Different Arid Habitats

Understanding the strategies and mechanisms of invasive species could guide their control and management especially in arid ecosystems. This study compares the vegetative and reproductive functional traits of the invasive Mexican poppy (Argemone ochroleuca), in seven habitat types, in southwestern Saudi Arabia. The results showed that the aboveground phenological attributes such as plant height, leaf area, and leaf dry mass attained the highest values in the wadi channels, whereas these attributes attained the lowest values in the mountain ranges. Maximum specific leaf area, root parameters, and all reproductive traits were recorded in the abandoned fields. In contrast to all other habitats, populations from abandoned fields had a greater investment of resources in belowground structures, while the population growing in the wadi channels and mountain ranges habitat allocated more energy to vegetative parts. The plasticity in vegetative and reproductive resource allocation in A. ochroleuca is an important mechanism in determining its colonizing ability in different habitat types and expanding the distribution range. The present data of the functional traits of A. ochroleuca agree with the resource fluctuation hypothesis, where the plant flourished in the abandoned fields that attained the highest values of organic matter and nutrients. Therefore, the restoration of these disturbed habitats could improve the resistance toward invasion by this noxious weed.