ABSTRACT
Climate change is considered to rank among the most important global issues affecting species' geographic distributions and biodiversity. Understanding effects of climate change on species can enhance conservation efficacy. In this study, we applied ecological niche modeling (ENM) using maximum entropy (MaxEnt) approaches to predict the potential geographic distribution of Achillea eriophora DC., a medicinal plant species to Iran in southwestern Asia, under current and future climate scenarios. We evaluated potential distributional areas of the species, under two shared socioeconomic pathways (SSP2-4.5 and SSP5-8.5) for the period 2041-2060. Most current potential suitable areas were identified for A. eriophora in montane regions. Our results anticipated that the potential distribution of A. eriophora will expand geographically toward higher elevations and northward. However, the species is expected to experience relatively high losses of suitability in its actual habitats under future climate scenarios. Consequently, we recommend regional-to-national conservation action plans for A. eriophora in its natural habitats.
ABSTRACT
Rising water scarcity, together with increased industrial wastewater production, suggests reusing of wastewater for plant irrigation. The wastewater from Razi petrochemical complex contained different salts and heavy metals. Variation in Brassica napus responses to wastewater irrigation has recommended appropriate levels of mineral nutrients in diluted wastewater that stimulated plant growth, and toxic levels of salts in undiluted wastewater that restricted plant growth. The undiluted wastewater irrigation significantly decreased chlorophyll fluorescence, along with photosynthetic capacity, while wastewater dilution mitigated its adverse effect. High levels of salts in undiluted wastewater induced an imbalance in plant mineral nutrients, which was evidenced with increased lipid peroxidation and reduced plant growth. On the contrary to adverse effects of undiluted wastewater on plant performance, the diluted wastewater, especially at 50% level, behaved as a fertilizer which increased leaf mineral nutrients, photosynthetic capacity, morphological and anatomical features of plant, but decreased lipid peroxidation. In relation to improvement in photosynthetic capacity, a significant increase was achieved in stomatal traits in plants irrigated with half-strength wastewater. In conclusion, due to the nutrition values of wastewater, it can be suggested to irrigate plants with diluted wastewater with the aim of improving crop productivity and saving freshwater sources.
ABSTRACT
Stevia rebaudiana Bertoni is a sweet medicinal herb that is cultivated worldwide. This study aimed to identify the genotypic responses and function of nine cultivars of S. rebaudiana (accession numbers 1-9 from the EUSTAS Stevia Gene Bank) to low temperature. Plants were grown in vitro and incubated under controlled conditions at 5° or 25°C for 1 month. Cold stress significantly decreased the maximum quantum yield of photosystem II (Fv/Fm) in all cultivars, which was more pronounced in cultivars 5, 6, 8, and 9. The efficiency of photosystems I and II (PIABS) also declined in cold-stressed plants and was accompanied by reductions in net photosynthesis (PN), intercellular CO2 (Ci), water use efficiency (WUE), and chlorophyll a, chlorophyll b and carotenoid contents, more so in cultivars 5, 6, 8, and 9. Regardless of the downregulation of photosynthetic capacity, the cold stress increased water-soluble carbohydrates in all cultivars, which was accompanied by an increase in fresh leaf mass and area, more so in cultivars 5, 6, 8, and 9. Furthermore, cold stress increased the stomatal index and density, epidermal cell density, stem diameter, xylem vessel width, phloem tissue width, and number of sclerenchyma in all cultivars. Even though the nine cultivars of S. rebaudiana had lower PSII efficiencies at low temperatures, the increase in carbohydrates and leaf mass suggests that damage to PSII is not responsible for the reduction in its efficiency.
