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Effects of salinity and drought on early seedling growth and survival of Artemisia herba-alba
Abstract and Figures
Seedlings of Artemisia herba-alba grown in glasshouse were watered with differing salinities (0, 150, 250 or 350 mM NaCl) and watering frequencies of 3, 7, 14 or 21 days for a period of 6 weeks. At the end of the study, plant survival, dry matter yield, biomass allocation (shoot and root), leaf area, relative growth rate (RGR), net assimilation rate (NAR), specific leaf area (SLA) and leaf area ratio (LAR) were recorded. When watered with 0 mM NaCl, Artemisia herba-alba plants had similar (P> 0.9) final dry matter weight and 100% survival regardless of watering frequency. However, plants did respond to watering frequency by allocating less biomass proportionately to below ground reserves as watering frequency decreased (P< 0.05). A threshold for survival of Artemisia herba-alba to cumulative salt concentrations above 20 g salt per kg soil was recorded. Once salinity concentrations passed the threshold, survival decreased dramatically from 80% at 30 g salt per kg soil to 60% at 70 g salt per kg soil. As well, within each level of watering frequency, as salt concentrations increased, seedling biomass decreased. Artemisia herba-alba’s drought tolerance makes it an ideal candidate on low salinity sites with low to moderate soil moistures.
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... However, the differences in the amount of EO produced may be attributed to a wide range of intricate and interconnected elements, which have been extensively studied and improved upon in recent years. Factors such as drying conditions, harvesting season, geographical location, fertilizer, soil pH, as well as intrinsic plant factors like chemotype, plant part employed, and genotype, have all been demonstrated to have a significant impact (Louhaichi et al., 2015;Elwardani et al., 2024). Furthermore, the choice of extraction process is also a crucial factor (Chebbac et al., 2023). ...
Introduction
Morocco is home to a remarkable diversity of flora, including several species from the Artemisia genus. This study aims to thoroughly examine the chemical composition of essential oils derived from Artemisia species and assess their antibacterial and antioxidant properties through in vitro experiments and in silico simulations.
Methods
Samples of Artemisia herba-alba Asso. were collected from Boulemane and Ifrane in Morocco, while Artemisia huguetii Caball. was sampled from Tata, representing regions of the Central Middle Atlas and Western Anti-Atlas. Essential oils were extracted using hydrodistillation, and their chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS). Antibacterial and antifungal activities were evaluated, and antioxidant properties were assessed using the DPPH assay. In silico predictions of antibacterial and antioxidant activities were performed using computational models.
Results
The extraction yields varied depending on the geographical origin, ranging from 1.54% to 2.78%. GC-MS analysis revealed significant differences in the chemical composition of the oils from different Artemisia species and regions, with a notable prevalence of oxygenated monoterpenes. Specifically, the oil from Boulemane was rich in thujone, the oil from Ifrane was predominantly composed of camphor, and the oil from Tata contained both camphor and thujone. The oils exhibited stronger antifungal than antibacterial properties, with Enterobacter cloacae strains showing high sensitivity, with minimum inhibitory concentrations (MIC) of approximately 12.5 mg/mL. The Boulemane oil of A. herba-alba displayed the highest antioxidant activity, effectively inhibiting DPPH at a concentration of 13.501 μg/mL.
Discussion
The in silico simulations predicted that the primary compounds in these essential oils, such as davanone, eucalyptol, camphor, and thujone, would exhibit potent antibacterial and antioxidant properties. These compounds were found to have favorable ADMET characteristics, including good blood-brain barrier permeability, gastrointestinal absorption, and skin penetration. Molecular docking studies revealed strong interactions between these compounds and key target proteins, such as NADPH-dependent catalase and dihydrofolate reductase. The stability of the protein-ligand complexes was confirmed by molecular dynamics, with davanone showing a significant impact. Overall, this study provides a comprehensive understanding of the biological potential of Artemisia essential oils, highlighting davanone as a promising molecule for medicinal or pharmaceutical applications.
... Mediterranean plants are adapted to extended periods of summer drought and they can cope with low soil water availability (Peñuelas 1996;Peñuelas et al. 2001; Micco and Aronne 2012), but they may still reach the limit of survival if drought events are getting too severe (Prévosto et al. 2011;Benigno et al. 2014;Louhaichi et al. 2015). Critical thresholds for survival vary among co-occurring plant species depending on specific morphological and physiological characteristics and life history traits (Grime 2001;Hernandez et al. 2010). ...
The increasing intensity and frequency of droughts predicted for the Mediterranean basin with ongoing climate change will impact plant communities and ecosystem functioning. This study investigated the effect of severe recurrent droughts and the role of the neighbor plant identity on the growth and survival of three abundant and co-existing species of a typical Mediterranean shrubland. Two juvenile plants, either of the same species or in all possible combinations of the two woody species Quercus coccifera and Cistus albidus and the perennial grass species Brachypodium retusum were grown together in rhizotrons under controlled watering regimes for two years. Compared to a treatment with only one drought cycle, three successive droughts reduced the relative growth rates (RGR) of shoots and roots in B. retusum, but not in woody species, and increased the mortality of the woody species, but not that of the grass. The survival of C. albidus and of B. retusum, but not of Q. coccifera, increased when the neighbor individual was a different species than when it was the same species. Our data suggest that both species composition and frequency of drought events will impact the dynamics of plant communities in Mediterranean shrublands under ongoing climate change. The abundance of dehydration sensitive woody species will likely decrease under more frequent drought events at the expense of dehydration-tolerant grass species, resulting in potentially strong changes in the functioning of these ecosystems.
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... Increase in salinity adversely affected the survival rates of the two growth stages of A. muricata seedlings but the 12 weeks old seedlings had higher survival rates than the six weeks old seedlings. Liu et al. (2010), Ahmad et al. (2014) and Louhaichi (2015) had equally observed a decrease in seedling survival rates with increased salinity levels on Helianthus annuus, cotton and Artemisia hera-alba, respectively. ...
This study evaluated seedling growth performances of two growth stages (6 and 12 weeks) of Annona muricata at different salinity levels-zero (0.00mgNaCl/l), slight (5000mgNaCl/l), medium (9000 mgNaCl/l) and high (14000mgNaCl/l), 4-weeks and 7-weeks after transplanting (WAT). The experiment was laid out in a Completely Randomized Design (CRD) for each of the two seedling growth stages. One-way analysis of variance was used to test for significant difference in growth attributes of each of the seedling growth stage among salinity levels while t-test was used to test for significant difference in each growth attribute between the two seedling stages. Seedling height and collar diameter in 6-weeks old seedlings 4-WAT reduced significantly (p < 0.05) between the high and each of the other salinity levels while leaf number varied significantly (p<0.05) between zero salinity and each of the other salinity levels. At 7-WAT, the reduction in height of the 6-weeks old seedlings was not significant (p≥ 0.05) among the salinity levels but the reduction in collar diameter and leaf number was significant (p < 0.05). Seedling height of the 12-weeks old seedlings 4-WAT was only significant (p<0.05) among the control, medium and high salinity levels while the reduction in collar diameter varied significantly between the control and each of the other salinity levels. The leaf number varied significantly (p < 0.05) between the control and each of the other salinity levels while there was no significant difference among the slight, medium and high salinity levels. At 7-WAT, reduction in height and collar diameter of the 12-weeks old seedlings was not significantly different (p≥0.05) among the control, slight and medium salinity levels while reduction in leaf number varied significantly among them. At 4-WAT, reduction in seedling height and collar diameter was significant (p<0.05) between the 6 and 12 weeks old seedlings at high salinity while leaf number varied significantly (p<0.05) between them at all the salinity levels. Both seedling stages could not survive at the high salinity 7-WAT; however, the 12-weeks old seedlings performed better at the other salinity levels; and generally had higher survival rates (up to 100% at slight salinity level). It is recommended that 12 weeks old seedlings of A. muricata be used for planting in agroecosystems with slight saline soil condition.
Longer drought periods and/or overall less precipitation are thought to be major consequences of ongoing climate change in the Mediterranean region. These changes in the water regime will likely affect community composition, biodiversity and ecosystem processes, but very little is known about how biodiversity and changes in precipitation interactively affect ecosystem functioning. In my PhD thesis, I aimed to quantify the role of plant diversity in the response of Mediterranean shrubland ecosystem to a decrease in water availability, with a particular interest in belowground processes, such as soil microbial community functioning and functional responses in plant roots.
I used a rhizotron approach under partially controlled conditions to study plant growth responses to repetitive severe droughts, with a particular focus on root growth. Two individuals of the same species or in all possible combinations of the three dominating species at our field site (Quercus coccifera, Cistus albidus, Brachypodium retusum) were grown together in a rhizotron. Repetitive severe droughts had a negative effect on survival of the two woody species (Q. coccifera, C. albidus), but not of the grass B. retusum. Interspecific competition generally increased survival of C. albidus and B. retusum compared to monospecific competition. Conversely, interspecific competition decreased the survival of Q. coccifera. Likewise, I found that root morphological traits were mostly affected by the neighbor species identity rather than by severe drought. The community level physiological profiles (CLPPs) of root associated soil microbial communities did not differ between drought treatments and were also not affected by plant species identity. However, CLPPs changed towards more total microbial activities but less diverse resource use at increasing soil depth. Collectively these results suggest that plant species composition of the studied Mediterranean shrubland has a stronger effect on growth, intraspecific variability in root traits and survival than repetitive severe droughts.
In the context of a larger collaborative project (CLIMED), I used a natural gradient of shrub species diversity in a Mediterranean shrubland ecosystem (garrigue) to which a permanent partial rain exclusion treatment (12% less precipitation) was added. This field experiment allowed me to study the responses of soil microbial community level physiological profiles (CLPPs) to reduced precipitation and to a change plant-produced leaf litter material decomposing on the ground as a key resource for heterotrophic soil microorganisms over two years. While rain exclusion had only a minor impact on the diversity of substrates metabolized by the microbial communities, litter species richness promoted global soil microbial activity by increased catabolic diversity of the soil microbial community. These results suggest that indirect climate change effects on plant species composition and richness might have more important consequences for soil microbial functioning than reduced precipitation in the studied Mediterranean shrubland ecosystem.
Both, the field study of soil microbial functioning and the rhizotron study of plant growth and survival clearly showed that plant species identity and diversity may be more important for the functioning of these Mediterranean shrublands than increased drought. I conclude that climate change induced shifts in plant species composition and diversity may have more important consequences for the functioning of Mediterranean shrublands than the direct effects of altered precipitation.
Salinity is one of the major environmental stresses that limit plant growth and productivity. In this study, the effects of salt stress on physiological and biochemical parameters were investigated in Hedysarum coronarium L. and Hedysarum criniferum species The NaCl treatments in Hoagland’s nutrient solution were: Control (no salt: 0.81 ds/m NaCl), 10.67, 20.33, 22.66 and 26.59 ds/m. Plants were irrigated with Hoagland’s nutrient solution during 4 months. Salt treatments were applied for 37 days. Gas exchange parameters, relative water content, proline, chlorophyll, carotenoids and stomata characteristics were measured. Data analysis showed that the measured parameters except intercellular CO2 concentration in both species were affected by salt stress. The lowest amount parameters measured, relative water content, proline, chlorophyll, carotenoids and stomata characteristics were observed at 26.59 ds/ m NaCl salinity. Proline and number stomata increased with increasing salinity in both species. In general, H. criniferum was more affected by salinity than H. coronarium. The results of this study suggested that H.coronarium is relatively better suited under salt stress conditions than H. criniferum. © 2017, Range Management Society of India. All rights reserved.
Changes in agro-pastoral production systems affect the livelihoods and development of rural communities. Thus it is important for planners and policy makers to be able to document land or ecosystem conditions and trends in relation to managerial actions at specific locations. Quantification of ecosystem parameters that are used for condition and trend assessment has been difficult, time consuming and expensive resulting in very few locations worldwide with detailed records. We report monitoring techniques that can be used at local scales, to speed up the collection, processing and storage of indicators of agroecosystem health. By coupling digital photography, differential global positioning systems technologies, information collected with accessory devices and computer software applied in a strict monitoring protocol enabled rapid sampling and recording geographic position (latitude/longitude) of quadrates (1 to 25 m2) with vegetation, litter and soil parameters. If vegetative species are visually distinctive, plants can also be identified. Repeated measurements over time at the same locations provide information regarding environmental trend and rate of change. Coupling our local scale measurements with landscape scale remote sensing data such as satellite or high altitude aerial photography, we have a complete picture of vegetation dynamics and system change, which facilitates interpretation
This study was conducted in farmers fields in northern Syria
to determine whether introduction of Mediterranean saltbush
(Atriplex halimus L.) in barley fields could increase feed
quantity without jeopardizing barley grain production. Seven
representative farmers were selected and barley (cv. Arabi
Aswad) was planted between the rows of Mediterranean
saltbush. Each field has a control selected randomly where
only barley was planted. The barley grain yield was increased
by 25% when associated with rows of Mediterranean
saltbush. There was a significant variation in barley yields
with distance from the hedgerows, and no interactions with
the site. The soil moisture at a depth of 3555 cm also
showed significant variation with distance from hedgerows.
Appropriate management of a limited water supply would be an effective tool to reduce production costs, minimize nutrient leaching,
and conserve water. Yarrow is considered a high value herbaceous perennial for landscape in United States, and have solid, matforming
rhizome/root system with fine feathery leaves which make it drought resistant. However, little information quantifies the
physiological performance of yarrow species under limited moisture and recovery from drought. Two yarrow species (Achillea
millefolium cv Cerise Queen and Achillea filipendulina cv Parker Gold) plants were subjected to four irrigation intervals: irrigated
daily (control), 3, 6 and 9 days under greenhouse conditions in 2004 and 2005. Irrespective of the species, the plants exposed to
drought had lower predawn leaf water potential (�pd), stomatal conductance (Sc), transpiration rate (Ts), cell osmotic potential (�
s),
and relative water content (RWC) than controls. Leaf area (LA), leaf weight (LW) and root weight (RW) of the controls were over
twice that of plants irrigated every 9 days in 2004 and over four times as high in 2005. Leaf area ratio (LAR) was lowest in the
control and increased with each level of drought stress. Root-to-shoot dry weight ratio (RSR) of the control was highest and
decreased with each stress level and lowest RSR was observed for plants irrigated every 9 days. Drought did not affect net
assimilation rate (NAR). In both years, relative growth rate (RGR) of the control was twice as high as plants irrigated every 9 days.
Both species performed better in irrigated conditions compared with drought stress. However, the production of larger leaf area (3209
cm2) heavier leaves (35.99 g) and better osmotic adjustment by the Cerise Queen specie in response to drought enabled it to deposit
more solute and lowered leaf water potential without dehydration than Parker Gold, and thus may be grown successfully on limited
moisture.
Goose populations that winter in Oregon's Lower Willamette Valley have increased from 25 000 to more than 250 000 birds in the last 25 years, resulting in heavy grazing of wheat and other crops. To map and document the extent and intensity of goose impacts on wheat fields, we combined rectified aerial photography with both globally positioned ground observations and vertical platform photographs. Aerial photos revealed areas of fields with sparse wheat cover while platform photos documented the cause. We estimated wheat cover in ground level photographs by ratioing red, green and blue digital numbers. From platform photographs we recorded occurrence of grazing (from grazed leaf tips), intensity of grazing (from residual plant cover and leaf length), and other indicators of goose use (footprints and droppings). Because the ground photographs were spatially positioned, we could use this information to verify the cause of "thin" wheat. Crop damage from grazing/trampling, water submergence, and other factors was evident. Our results illustrate practical ways to combine aerial and ground-level image analysis, spectral observations, and global positioning systems to quantify field conditions in wheat.
The determination of phytomass and the assessment of actual and potential primary production of a natural ecosystem has become an important part of modern ecological research. In order to understand the functioning of an ecosystem, to analyse it, and to build valid models (see van Keulen et al., this volume Part 6:B), exact phytomass and production data must be available. This general aim, however, is difficult to approach, since phytomass and primary production are not constant values (see Lieth, this volume Part 6: A). Even for the same habitat they depend upon the total environmental conditions which are changing from year to year. Therefore, the fluctuations of phytomass and production and their relation to the environmental parameters need to be considered. This problem may be of minor importance for ecosystems living in humid environments. It is of great significance, however, in arid and semi-arid areas, where the main factor limiting phytomass and production is the availability of water. It is precisely this factor which in these regions fluctuates to a very large degree from year to year.
In the Northern Negev (Israel) annual plants are more numerous on south-facing slopes dominated by Zygophyllum dumosum than on north-facing slopes dominated by Artemisia herba-alba. On the latter slopes annuals are fewer in the vicinity of A. herba-alba than elsewhere. In the year following experimental removal of Artemisia plants the number of annuals increased, but remained smaller than on the south-facing slope. Unless there are differences in soil seed reserves, this suggests an inhibitory after-effect due to Artemisia. Experimental evidence is presented for the release from A. herba-alba shoots of volatile and water-soluble substances which strongly inhibit the germination of Helianthemum ledifolium and Stipa capensis. In Zygophyllum dumosum and cultivated tomato germination was less strongly inhibited, and in Medicago laciniata var. laciniata and var. brachyacantha not at all. No inhibition was exerted by Zygophyllum dumosum leaves. The inhibition of Stipa capensis and tomato by aqueous extracts of Artemisia shoots was to some degree reversible by short periods of leaching. The possible role of chemical inhibition of certain annuals in stands of A. herba-alba is discussed.
Seeds of greasewood (Sarcobatus vermiculatus (Hook.) Torr.) were germinated at 5° to 40° C in 5-degree increments to determine temperature response. Seeds were also germinated in solutions of polyethylene glycol 6,000 (PEG), NaCl, and Na2 SO4, each at osmotic potentials of 0 to -4.2 MPa in -0.3 MPa decrements at 10, 20 and 30° C to determine moisture stress, specific ion, and temperature interaction. Germination was high at all temperatures, 5° C through 25° C being optimal. A direct linear relationship existed between total germination and osmotic potential of each solution at each temperature. Mean germination at 30° C was significantly different for each osmotica with NaCl highest and PEG lowest. Mean germination at 10° C and 20° was not different within osmotica; however, total germination was significantly lower in PEG than in NaCl and Na2 SO4, indicating the difference between macromolecular PEG and ions ( ). Significant difference was observed in the coefficient of rate of germination between ions of Cl- and , with being more stressful.
The arid rangelands of Syria cover over half of the nation's landmass. Punctuating this landscape are broad, dry basins, or wadis, and gentle landscape depressions that exhibit localized elevated vegetation productivity and unique edaphic and hydrologic properties. Historically, continuous heavy grazing and aggressive agricultural activities resulted in excessive ecological degradation within these sensitive environments. Information is needed to determine the influence of livestock grazing on plant communities in landscape depressions and the impact that this has on ecosystem resilience. The purpose of this research is to evaluate the effect of short-term sheep grazing on vegetation characteristics and plant community structure within depressions, and to provide recommendations for improved grazing management. Study plots were randomly located within paired topographic depressions located in northwestern Syria. Vegetation samples were collected along transects including plant biomass, plant density, herbaceous cover, and species diversity. In grazed plots, plant biomass was 49 g DM/m2 compared to 234.4 g DM/m2 in protected plots. Average plant density was 65 plants/m2 in grazed plots compared to 1013 plants/m2 in protected plots (P = 0.001). Herbaceous cover was 175% higher on protected sites compared to grazed plots. Average diversity (Shannon–Wiener index value) was 0.8 in grazed plots compared to 2.3 in protected plots. These results suggest that plant community structure will be impacted from short-term grazing and that a site's ability to positively respond to disturbance over time may be limited. We conclude that carefully planned grazing management should result in greater plant productivity and diversity.