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Background: Despite the exposure to arid environmental conditions across the globe ultimately hampering the sustainability of the living organism, few plant species are equipped with several unique genotypic, biochemical, and physiological features to counter such harsh conditions. Physiologically, they have evolved with reduced leaf size, spines, waxy cuticles, thick leaves, succulent hydrenchyma, sclerophyll, chloroembryo, and photosynthesis in nonfoliar and other parts. At the biochemical level, they are evolved to perform efficient photosynthesis through Crassulacean acid metabolism (CAM) and C4 pathways with the formation of oxaloacetic acid (Hatch-Slack pathway) instead of the C3 pathway. Additionally, comparative genomics with existing data provides ample evidence of the xerophytic plants' positive selection to adapt to the arid environment. However, adding more high-throughput sequencing of xerophyte plant species is further required for a comparative genomic study toward trait discovery related to survival. Learning from the mechanism to survive in harsh conditions could pave the way to engineer crops for future sustainable agriculture. Aim of the review: The distinct physiology of desert plants allows them to survive in harsh environments. However, the genomic composition also contributes significantly to this and requires great attention. This review emphasizes the physiological and genomic adaptation of desert plants. Other important parameters, such as desert biodiversity and photosynthetic strategy, are also discussed with recent progress in the field. Overall, this review discusses the different features of desert plants, which prepares them for harsh conditions intending to translate knowledge to engineer plant species for sustainable agriculture. Key Scientific Concepts of Review: This review comprehensively presents the physiology, molecular mechanism, and genomics of desert plants aimed towards engineering a sustainable crop.

Pugionium cornutum is an annual or biennial xerophyte distributed in arid regions, with drought resistance properties. While previous studies have predominantly focused on the physiological changes of P. cornutum, the understanding of its metabolite variations remains limited. In this study, untargeted metabolomic technology was performed to analyse the change of metabolites in the roots of P. cornutum seedlings under drought stress. Our findings revealed that compared to the R1, the root water potential and the number of lateral roots increased, while the length of the tap root and fresh weight increased first and then decreased. In the R1–R2, a total of 45 differential metabolites (DMs) were identified, whereas in the R1–R3 82 DMs were observed. Subsequently, KEGG analysis revealed a significant enrichment of microbial metabolism in diverse environments and aminobenzoate degradation in the R1–R2, and phenylpropanoid biosynthesis, ubiquinone, and other terpenoid-quinone biosynthesis and isoquinoline alkaloid biosynthesis were significantly enriched in the R1–R3. The upregulation DMs, including L-arginosuccinate, L-tyrosine, p-coumarate, caffeate, ferulate, vanillin, coniferin, 5-aminopentanoate, 2-methylmaleate and 2-furoate in P. cornutum seedlings may play a crucial role in enhancing root growth and improving drought resistance. These findings provide a basis for future investigations into the underlying mechanisms of drought resistance in P. cornutum. [ABSTRACT FROM AUTHOR]

[Display omitted] • Desert is one of the harshest places on the earth due to low precipitation and soil nutrients. • Global desertification is a continuous process; almost 60% of the land surface is now desertified. • The plants in these desert ecosystems have developed several novel phenotypic characteristics that overcome the harsh environment. • Genome sequencing of the desert plant can enable us to identify the novel trait responsible for overcoming the xerophytic condition. • Transfer of novel genetic traits can be done to the crop plants. So that plants can withstand the harsh environment and overcome crop loss due to drought and other extreme conditions. Despite the exposure to arid environmental conditions across the globe ultimately hampering the sustainability of the living organism, few plant species are equipped with several unique genotypic, biochemical, and physiological features to counter such harsh conditions. Physiologically, they have evolved with reduced leaf size, spines, waxy cuticles, thick leaves, succulent hydrenchyma, sclerophyll, chloroembryo, and photosynthesis in nonfoliar and other parts. At the biochemical level, they are evolved to perform efficient photosynthesis through Crassulacean acid metabolism (CAM) and C4 pathways with the formation of oxaloacetic acid (Hatch-Slack pathway) instead of the C3 pathway. Additionally, comparative genomics with existing data provides ample evidence of the xerophytic plants' positive selection to adapt to the arid environment. However, adding more high-throughput sequencing of xerophyte plant species is further required for a comparative genomic study toward trait discovery related to survival. Learning from the mechanism to survive in harsh conditions could pave the way to engineer crops for future sustainable agriculture. The distinct physiology of desert plants allows them to survive in harsh environments. However, the genomic composition also contributes significantly to this and requires great attention. This review emphasizes the physiological and genomic adaptation of desert plants. Other important parameters, such as desert biodiversity and photosynthetic strategy, are also discussed with recent progress in the field. Overall, this review discusses the different features of desert plants, which prepares them for harsh conditions intending to translate knowledge to engineer plant species for sustainable agriculture. This review comprehensively presents the physiology, molecular mechanism, and genomics of desert plants aimed towards engineering a sustainable crop. [ABSTRACT FROM AUTHOR]

Dune is often considered as a degraded ecosystem. Natural vegetation restoration and stable artificial vegetation construction are the basic means restoring dune ecosystem. Based on long-term study of dune ecosystem, by taking into consideration both the philosophical principles of unity of opposites and dynamic change, and related ecological theories, we put forward some ecological relations that should be paid attention to in the study of vegetation assembly from the perspective of the uniqueness of dune ecosystem. We discussed the necessity of coupling relationships of scale-pattern-process and the transformation of synergy-tradeoff relationships, interpreted the importance of distinguishing sand dune stabilized and shifting phases, disturbance and stress, wind erosion and sand burial in the study of vegetation process. We further explored the applied value of niche law or neutral law in the study of dune vegetation process. Finally, we discussed the issues that should be paid attention to in the study of dune vegetation process from the aspects of adaptability to aeolian activities and drought tolerance, physiological and reproductive process, sexual and asexual reproduction of plants. This study would provide theoretical supports for vegetation restoration and stable vegetation construction of dune ecosystem. [ABSTRACT FROM AUTHOR]

Background and Aims Bulnesia retama is a drought-deciduous, xerophytic shrub from arid landscapes of South America. In a survey of carbon isotope ratios (δ13C) in specimens from the field, B. retama exhibited less negative values, indicative of CAM or C4 photosynthesis. Here, we investigate whether B. retama is a C4 or CAM plant. Methods Gas-exchange responses to intercellular CO2, diurnal gas-exchange profiles, δ13C and dawn vs. afternoon titratable acidity were measured on leaves and stems of watered and droughted B. retama plants. Leaf and stem cross-sections were imaged to determine whether the tissues exhibited succulent CAM or C4 Kranz anatomy. Key Results Field-collected stems and fruits of B. retama exhibited δ13C between −16 and −19 ‰. Plants grown in a glasshouse from field-collected seeds had leaf δ13C values near −31 ‰ and stem δ13C values near −28 ‰. The CO2 response of photosynthesis showed that leaves and stems used C3 photosynthesis during the day, while curvature in the nocturnal response of net CO2 assimilation rate (A) in all stems, coupled with slightly positive rates of A at night, indicated modest CAM function. C4 photosynthesis was absent. Succulence was absent in all tissues, although stems exhibited tight packing of the cortical chlorenchyma in a CAM-like manner. Tissue titratable acidity increased at night in droughted stems. Conclusions Bulnesia retama is a weak to modest C3 + CAM plant. This is the first report of CAM in the Zygophyllaceae and the first showing that non-succulent, xerophytic shrubs use CAM. CAM alone in B. retama was too limited to explain less negative δ13C in field-collected plants, but combined with effects of low stomatal and mesophyll conductance it could raise δ13C to observed values between −16 and −19 ‰. Modest CAM activity, particularly during severe drought, could enable B. retama to persist in arid habitats of South America. [ABSTRACT FROM AUTHOR]

In this study, a collection of promising endophytic bacterial strains F. solani, R. solani, Aspergilus isolated from some halophyte and xerophyte plants. sp., Alternaria sp. the results of research on determining antifungal activity in vitro against phytopathogenic fungi such as The obtained information can serve to increase the variety of tools used in the fight against fungal diseases of agricultural crops.

The objective of this study was to evaluate the productive performance and carcass characteristics of confined Santa Inês sheep, fed different diets, in a Semiarid environment. Twenty whole sheep with 5 ± 0.5 months of age and 27 ± 2.0 kg were used, receiving two different diets for 72 experimental days, one composed of defatted soybean meal and the other of protein-enriched cactus meal. They were evaluated for different diets, consumption, production, carcass characteristics, morphometric measures and edible components. The experimental design was in randomized blocks with two treatments and '0 replications. Performance data and carcass characteristics were evaluated by analysis of variance and means compared by t test at 5% probability level using Statistical Analysis System [SAS]® (1999). Thus, the use of emulsified palm forage protein in the feeding of Santa Inês male lambs proved to be an excellent protein source when compared to the use of defatted soybean meal, since the results of performance and carcass characteristics were similar, being the use of this alternative source advised as it presents the best benefit-cost ratio. [ABSTRACT FROM AUTHOR]

As a crucial aspect of terrestrial ecosystems, water plays a key role in soil hydrological cycling and ecological management. However, limited knowledge exists on how soil water varies along rock fragment content (RFC) beneath plants. In this study, we investigated soil water content (SWC) and relative soil water deficit (DSWC) with four RFC levels ranging from 0 to 75 % (V/V) under four native species, including A. vestita , B. brachycarpa , C. szechuanensis , and S. davidii , and their relationships with soil physical properties and plant functional traits. Results showed that an increase in RFC significantly decreased SWC (except A. vestita) at soil depth of 10–50 cm and altered its vertical trend from unimodal to increasing under each plant. Notable differences in SWC between the wet and dry seasons in 75 % RFC disappeared under A. vestita and B. brachycarpa , suggesting that the RFC changed the spatiotemporal patterns of the SWC. DSWC generally decreased as soil depths deepened under A. vestita with shallow roots, in contrast to increasing under other deep-rooted species (B. brachycarpa , C. szechuanensis , and S. davidii). The seasonal variance of DSWC basically decreased with soil depth. This indicated that the plants generally deceased SWC, particularly in the wet season, and the effect depended on interspecific traits. SWC and DSWC had closely relationships with soil physical properties and plant performing. We suggest that varying RFC indirectly impacted soil water not only via altering soil structure and temperature, but also by shaping plant characteristics (especially root distribution and architecture), mediating plant effect on the spatiotemporal dynamics of SWC. [ABSTRACT FROM AUTHOR]

Key message: Desert woody species demonstrated a high morphological plasticity to water. This would allow them to use increased rainfall predicted by climate change, but might challenge the drought resistance of irrigated nursery-produced plants for revegetation. Phenotypic plasticity is the ability of a given genotype to produce different phenotypes in response to changing environmental conditions. Despite its high adaptive value, it may have a high cost in resource-poor ecosystems, restricting the ability of plants to take advantage of surplus resources, e.g., increased levels of precipitation. We aimed to determine the phenotypic plasticity to water availability of four woody species from a hot desert of South America. We carried out a pot experiment with two levels of irrigation in a glasshouse, where performance (biomass production, stem growth, survival) and functional traits (biomass allocation, total leaf area, leaf size, specific leaf area; stomata size, density and index; photoprotective and antioxidant compounds) were measured. The plasticity patterns differed between species, with the highest plasticity in leaf traits (around 80% change between treatments), and the lowest in biochemical traits (no significant variation between treatments). All four species increased their performance under high-water supply, with different magnitudes (the two phreatophytes > the two xerophytes). However, some of them showed increased allocation to stem biomass, increased total leaf area and leaf size, increased stomata size, and reduced root growth, potentially allowing them to use water for growth when it is available, although hampering their drought resistance, based on classic interpretation of traits' adaptive value. These changes promoted in irrigated nursery-produced seedlings should be considered in dryland revegetation plans. Moreover, our results suggest that the patterns of phenotypic plasticity would not be associated with the functional group of the species in relation to access of the water table in the field, but this issue needs to be explored further. [ABSTRACT FROM AUTHOR]

Purpose: Different from most crops and forages, the xerophyte Pugionium cornutum can absorb high quantities of Cl− and then efficiently transport them into shoots to enhance osmotic adjustment ability under salt stress. However, the molecular mechanism underlying long-distance Cl− transport remains unclear. SLAH1 is crucial for root-to-shoot Cl− transport in Arabidopsis only under non-saline conditions. This study aimed to evaluate the function of PcSLAH1 from P. cornutum in long-distance Cl− transport under salt stress. Methods: PcSLAH1 was cloned, its tissue and subcellular locations and expression patterns in response to salt treatments were analyzed. The effect of PcSLAH1 on ion accumulation and the expression of key genes involved in Na+ and Cl− transport were investigated by ectopically overexpressing in Arabidopsis driven by a root stelar-specific promoter. Results: PcSLAH1 was specifically expressed at root stelar cells and located on the plasma membrane. Opposing with AtSLAH1 in Arabidopsis, the relative expression level of PcSLAH1 in roots was significantly induced by high Cl− treatments. The root stelar-specific expression of PcSLAH1 in Arabidopsis resulted in a significant increase in shoot Cl− content under NaCl or KCl treatment. PcSLAH1 could coordinate with CLCg and NHX1 to regulate shoot Cl− and Na+ homeostasis under salt treatment. In addition, the root stelar-specific expression of PcSLAH1 conferred a stronger long-distance transport ability of Cl− than AtSLAH1. Conclusions: PcSLAH1 functions in facilitating the long-distance transport of Cl− and modulating shoot Na+ and Cl− homeostasis under salt stress. The up-regulated expression of PcSLAH1 is conducive to salt tolerance of P. cornutum. [ABSTRACT FROM AUTHOR]

Orthotrichum Hedw. s.l. and Ulota Mohr s.l. are two of the most speciose genera of the xerophytic moss family Orthotrichaceae. We reconstructed the phylogeny of these two genera using three data matrices: (i) organellar genomes and 33 taxa; (ii) six loci from three genomes and 144 taxa; and (iii) two plastid loci and 163 taxa. The present phylogeny, based on the maximum sampling of genes or taxa to date, generally confirms the new classification of Orthotrichum and Ulota, and indicated that all Ulota species, except Ulota phyllantha Brid., form a clade and three lineages comprise the cryptoporous Orthotrichum clade. We provided new morphological characters that support the present division of the two genera. Ancestral state reconstruction of stoma indicates that superficial stomata in Orthotrichum represent a plesiomorphic character and semi‐immersed stomata were derived from immersed stomata. The results also suggest that immersed stomata independently arose once in Orthotrichum, whereas semi‐immersed stomata probably arose more than once. Molecular dating analysis reveals that the occurrence of immersed stomata is probably related to arid environments during the early Oligocene to late Miocene, whereas the appearance of semi‐immersed stomata might be associated with the mesic–xeric or semiarid environments during the middle Miocene to Pliocene. Ancestral state reconstruction of habitat indicates that the saxicolous habitat is apomorphic and independently evolved multiple times in Orthotrichum and Ulota, which supports the former hypothesis. Considering morphological statistics, the development of the cryptopore in Orthotrichum could provide increased resilience to dry habitats, and might promote their habitat shift during evolution. [ABSTRACT FROM AUTHOR]

Elaeagnus moorcroftii Wall. (Elaeagnaceae) is an important tree species naturally growing in arid Northwest China that has great economic and ecological values in drylands. In this study, we de novo assembled a chromosome-level genome for E. moorcroftii by using PacBio's high-fidelity (HiFi) sequencing and Hi-C-assisted assembly technology. The assembled genome size was 529.56 Mb, of which 94.56% was anchored to 14 pseudochromosomes with a contig N50 up to 28.21 Mb. In total, 29,243 protein-coding genes were annotated, and 98.5% of the Benchmarking Universal Single-Copy Orthologs (BUSCOs) were captured in the genome. Evolutionary genomic analysis showed that E. moorcroftii split with Elaeagnus mollis 9.38 million years ago (Ma), and contrasted evolutionary trajectories of gene family expansion and contraction were observed for these two closely related species. Furthermore, we identified two successive whole genome duplication (WGD) events occurred in the genome of E. moorcroftii, in addition to the ancient gamma hexaploidization event shared by core eudicots. Together, the chromosome-level genome assembly for E. moorcroftii decoded here provides valuable genomic information for the further genetic improvement and molecular breeding of this indigenous species in drylands. [ABSTRACT FROM AUTHOR]

Haloxylon ammodendron is a xerophytic perennial shrub or small tree that has a high ecological value in anti-desertification due to its high tolerance to drought and salt stress. Here, we report a high-quality, chromosome-level genome assembly of H. ammodendron by integrating PacBio's high-fidelity sequencing and Hi-C technology. The assembled genome size was 685.4 Mb, of which 99.6% was assigned to nine pseudochromosomes with a contig N50 value of 23.6 Mb. Evolutionary analysis showed that both the recent substantial amplification of long terminal repeat retrotransposons and tandem gene duplication may have contributed to its genome size expansion and arid adaptation. An ample amount of low-GC genes was closely related to functions that may contribute to the desert adaptation of H. ammodendron. Gene family clustering together with gene expression analysis identified differentially expressed genes that may play important roles in the direct response of H. ammodendron to water-deficit stress. We also identified several genes possibly related to the degraded scaly leaves and well-developed root system of H. ammodendron. The reference-level genome assembly presented here will provide a valuable genomic resource for studying the genome evolution of xerophytic plants, as well as for further genetic breeding studies of H. ammodendron. [ABSTRACT FROM AUTHOR]

In the context of the absence of any prior art on the vermicomposting of any xerophyte—presumably because xerophytes, in general, are structurally tough and have attributes which help them resist biodegradation—the present work has been undertaken. It has led to a procedure which makes even the highly toxic leaves of prosopis amenable to vermicomposting. Two years long and continuous operation of vermireactors with six different species of earthworms, has shown that the earthworms gradually adapted to prosopis as their exclusive feed, showing a consistently increasing rate of vermicast production while remaining healthy and displaying good fecundity throughout. The work provides an avenue of utilizing prosopis leaves which are generated in very large quantities across the tropical and sub-tropical world. At present no process exists which can make use of prosopis leaves even as the wood of its trees is utilizable. Besides valorizing an otherwise wasted phytomass the present work will also prevent falling of prosopis leaves on soil and their very slow biodegradation during which they toxify the soil with allelochemicals and emit global warming gases. [ABSTRACT FROM AUTHOR]

Watermelon, [Citrullus lanatus var. lanatus L] is a major crop in Africa, especially facing the harsh effects of climatic change. It is a xerophytic crop that can be grown in subtropical and tropical parts of the world. Some constrains in commercialization of watermelon production are related to agronomic practices, post-harvest management and value-addition in Africa. Several products can be made from watermelon seeds, rind as well as their pulp, thereby boosting the food industry through its materials. However, watermelon production in Africa is hindered by several constrains, like weeds, pests, diseases and poor post-harvesting management. For the realization of true potential of watermelon production in Africa, more research is needed to come up with varieties which are tolerant to pests, diseases and weeds. The awareness in communities on its importance as a commercial crop in drought-prone areas also need attention. [ABSTRACT FROM AUTHOR]

This study aimed to develop an anatomy atlas about selected hydrophyte and xerophyte structural strategies as an enrichment learning medium. The Analysis, Design, Development model was used. The participants included a material expert, a media expert, biology teachers, and students of SMA Negeri 1 Wonosari at Grade XI. Data were collected using material and media expert validation sheets and questionnaires conducted with teachers and students which had been modified from other research instruments. The results were analyzed qualitatively. The anatomy atlas that was developed received favorable results, with an average value of 88.53% validity rate. Based on these results, the developed anatomy atlas would be useful for enrichment programs. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the leaf anatomy of Jacquinia armillaris plants in two different Venezuelan xeric shrublands to evaluate possible variations caused by the environments, which differ in rainfall and soil salinity. Leaf samples were collected in two sites: La Tortuga Island, a dryer and salty environment than the other collecting site, Turpialito, a coastal location in the mainland. The epidermis and the mesophylls were observed with a light microscope and measured with an ocular micrometer inserted in one of the eyepieces. The results show that J. armillaris has many characteristic anatomical traits of xerophytes, among them: thick cuticles and thick epidermis in both leaf surfaces, stomata only in the abaxial side and epidermal depressions lodging a glandular trichome. Leaves are bifacial and present multistratified palisade parenchyma facing the adaxial epidermis and abaxial spongy parenchyma with abundant intercellular spaces. Furthermore, the hypodermis is composed of one or two cell layers below the upper epidermis. Leaf lamina dimension, petiole, cuticles, epidermis and hypodermis cells, as well as the stomatal occlusive cells and number of trichomes, had differences in size and number when the plants of both sites were compared, being higher in plants from La Tortuga. On the other hand, palisade parenchyma and stomatal density were higher in Turpialito plants. Plants collected in La Tortuga Island showed characteristics that suggest adaptation to the island's saline and more arid conditions in comparison to plants from Turpialito, which presented more leaf traits related to adaptations to water deficit. These results demonstrate the phenotypic plasticity of J. armillaris plants that grow in two different xeric shrublands. [ABSTRACT FROM AUTHOR]

Jatropha (Euphorbiaceae) is a morphologically diverse genus with pantropical distribution. It includes 180 species growing worldwide and has a broad range of uses: medicinal, ornamental and biodiesel production. In Argentina there are ten native species, distributed from the north to the center of the country, and one adventitious. However, the morphoanatomy of the native species of Jatropha is scarcely known, and so far, no anatomical studies of the stem with secondary growth have been performed in any of the native species. In this work, we analyzed the anatomy of the stem with secondary growth of three native species: J. excisa, J. hieronymi and J. macrocarpa, considering aspects related to the arid environment in which plants live, to provide information that it is useful for their conservation and possible sustainable use. Woody branches of each species were collected and fixed to perform temporary histological preparations of transverse and longitudinal sections of stems. We described their morphoanatomy under a light microscope. The following variables were analyzed: xylem area/total area of the stem, number of vessels per mm2, vessel diameter and length of conductive elements. Indices were obtained to assess the drought vulnerability, the plant mesomorphy degree and to determine vessel clustering. The stems analyzed have several anatomical characters that are typical of plants that inhabit xerophytic environments, and that favor their development despite the scarce rainfall and high temperatures, including: suber and phelodermis with thickened cell walls; inner cortex with various cell layers; presence of chollenchyma; presence of chlorenchyma; ergastic substances in the cortex, vascular tissues and medullary parenchyma (latex, crystals and starch granules); short, narrow, numerous and grouped xylem vessels. The evaluated indexes suggest that the three taxa have a safe and efficient conduction system for water movement, being J. macrocarpa the most drougth resistant. This study provides novel information about these three species of biological, industrial, and economic importance, which are potential sources for biodiesel production. [ABSTRACT FROM AUTHOR]

Hl the current research, some soil properties and growh of camelthorn (Alhagi maurorum Medik.) were monitored in saline lands in Yazd Province during 2019-2020. Accordingly, the ability of this species was determined for growing in saline lands. For this purpose, seven rangelands in Yazd consisting of Bafgh, Javadieh, Bahabad, Jolgeh, Ardakan, Aghda, and Abarkooh were selected, in which Alhagi was dominant vegetation. The salinity of saturated extract (ECe) and pH of the soil, salinity and pH of water, fresh and dry weight were measured by sampling, and apparent soil salinity (ECa) was assessed by electromagnetic induction device (EM38). The results showed that regression coefficients (R2) of estimating soil salinity using EM38 devices in different regions were accepted and varied between 0.52-0.86. Soil salinity levels varied over the surveyed lands from 2.17 g salt/kg soil in Aghda to 226.5 g salt/kg soil in Ardakan for 0-30 cm soil depth and from 0.4 g salt/kg soil in Bafgh to 118.3 g salt/kg soil in Ardakan for 30-60 cm soil depth. The maximum production of ryegrass, equal to 25 tons ha-1 of fresh weight and 7 tons ha-1 of dry weight, was observed in Bafgh with water salinity of 12 dS m-1 and soil salinity of 11 g kg-1. On average, the highest production was observed in Bafgh, Bahabad, Abarkooh, Aqda, and Ardakan, respectively, which was almost consistent with changes in soil salinity and acidity. It seems that Alhagi has a high tolerance to water and soil salinity; however, it is sensitive to soil pH. The use of the EM38 device to evaluate soil salinity in lands with camelthorn cover of Yazd province was reasonably accurate and recommended for monitoring the soil salinity of other rangelands. However, calibration in each area and for each soil depth separately is necessary. [ABSTRACT FROM AUTHOR]

There is a growing realization in African countries for the need to enhance the production of xerophytic crops, including Watermelon, Citrullus lanatus L., in the face of climate change. The objective of this review is to explore challenges and opportunities in watermelon production in Africa. Watermelon is adaptable to most of tropical, and subtropical, Africa, due to its low water requirement and has the potential to be a commercial crop. However, minimal research has been applied to its breeding and production in the continent. Lack of improved varieties, poor production systems, perishable nature of the fruit, and lack of harvest and post-harvest preservation technology hamper large-scale production. Research, particularly in watermelon production practices and breeding, is needed if its true potential in Africa is to be realized. [ABSTRACT FROM AUTHOR]

The succulent xerophyte Zygophyllum xanthoxylum (Bunge) Engl. can absorb Na+ from the soil as an osmoticum in order to resist osmotic stress. The tonoplast Na+/H+ antiporter ZxNHX1 is essential for maintaining the salt-accumulation characteristics of Z. xanthoxylum by compartmentalizing Na+ into vacuoles. Previous results revealed that the silencing of ZxNHX1 greatly decreased Na+ accumulation in Z. xanthoxylum under 50 mM NaCl due to the weakened compartmentalisation; in addition, K+ concentration also significantly reduced in ZxNHX1 -RNAi lines. Yet, whether the reduction of K+ concentration was directly triggered by the silencing of ZxNHX1 remains unclear. In this study, the growth parameters and expression levels of ZxSOS1 , ZxHKT1 ; 1 , ZxAKT1 and ZxSKOR were measured in wild-type and ZxNHX1 -RNAi lines under control or –0.5 MPa osmotic stress. The results showed that the silencing of ZxNHX1 inhibited the plant growth, decreased Na+ concentration in leaves, reduced the transcript abundance of ZxSOS1 and dramatically increased that of ZxHKT1 ; 1 in roots of Z. xanthoxylum under osmotic stress; whereas tissue K+ concentrations and the expression level of ZxSKOR displayed no significant variations, and the expression of ZxAKT1 were significantly reduced in ZxNHX1 -RNAi lines under osmotic stress, compared with the wild type. These results suggest that in Z. xanthoxylum , ZxNHX1 can maintain the normal growth by compartmentalizing Na+ into vacuoles, and regulate the spatial distribution of Na+ indirectly by affecting the expressions of ZxSOS1 and ZxHKT1 ; 1. Moreover, the silencing of ZxNHX1 is not the main reason that led to the reduction of K+ concentration in ZxNHX1 -RNAi lines under 50 mM NaCl, and ZxNHX1 might be indirectly involved in regulating K+ homeostasis. In Zygophyllum xanthoxylum , a xerophytic shrub, the silencing of ZxNHX1 (tonoplast Na +/ H + antiporter) triggered the reduction of Na+ and K+ concentration under 50 mM NaCl treatment. In this work, the K+ concentration displayed no significant variation in ZxNHX1 -RNAi lines compared with the wild type under osmotic stress, indicating that ZxNHX1 might not directly participate in controlling K+ homeostasis. The results provide a basis for further researches on the transport of Na+ and K+ in Z. xanthoxylum. [ABSTRACT FROM AUTHOR]

Plant formations that develop on the edges of streams or bodies of water located in the border area between water and land. They are made up of specific stands due to the presence of water over more or less long periods, formations characteristic of the Oueds in our region. Riparian forests play an important ecological role. In particular, they offer specific natural habitats. They form biological corridors, increase the ecological connectivity of landscapes and therefore play a major role in maintaining biodiversity (forest and river biodiversity in particular), at regional scales. Finally, true filters, they protect the quality of the water and part of the wetlands of the watershed, the banks and the riparian soils. Our study is interested in the botanical and phytoecological aspect of endemic grouping of our Oued which are the tamaricaceae. [ABSTRACT FROM AUTHOR]

Elaeagnus moorcroftii Wall. (Elaeagnaceae) is an important tree species naturally growing in arid Northwest China that has great economic and ecological values in drylands. In this study, we de novo assembled a chromosome-level genome for E. moorcroftii by using PacBio’s high-fidelity (HiFi) sequencing and Hi-C-assisted assembly technology. The assembled genome size was 529.56 Mb, of which 94.56% was anchored to 14 pseudochromosomes with a contig N50 up to 28.21 Mb. In total, 29,243 protein-coding genes were annotated, and 98.5% of the Benchmarking Universal Single-Copy Orthologs (BUSCOs) were captured in the genome. Evolutionary genomic analysis showed that E. moorcroftii split with Elaeagnus mollis 9.38 million years ago (Ma), and contrasted evolutionary trajectories of gene family expansion and contraction were observed for these two closely related species. Furthermore, we identified two successive whole genome duplication (WGD) events occurred in the genome of E. moorcroftii, in addition to the ancient gamma hexaploidization event shared by core eudicots. Together, the chromosome-level genome assembly for E. moorcroftii decoded here provides valuable genomic information for the further genetic improvement and molecular breeding of this indigenous species in drylands.

Salvadora oleoides Decne. (Salvadoraceae) is a facultative and mesomorphic xerophyte, well adapted to arid and semi-arid regions. Twelve populations were selected from different ecological regions of Punjab to investigate structural modifications that are essential for water conservation, by either improving water-storing capacity or preventing water loss from the plant body, hence, enabling this species to cope with environmental extremities. We observed significant plasticity in structural features, which ensures ecological success in a variety of environmental conditions. Huge variation was seen in various tissue systems, i.e., epidermis and epidermal appendages, collenchyma, size of internal oil glands, storage parenchyma, shape, size and arrangement of vascular tissue, intensity of sclerification, and stomatal size, shape and orientation. The desert populations showed additional parenchymatous layer under multilayered epidermis, xylem completely surrounded by phloem, broad metaxylem vessels, intensive sclerification in and outside vascular tissue, and numerous and small sized stomata on abaxial leaf surface. Population from salt-affected areas showed greater stem cross-sectional area, enlarge palisade parenchymatous cells, multilayered epidermis, large storage parenchyma, and sclerified vascular bundles. Roadside populations possessed sclerified vascular bundles and dense hairiness on leaf surface. [ABSTRACT FROM AUTHOR]

The Tequila industry produces agave bagasse, which in most cases is transformed into ash to reduce its volume. Here we present the synthesis of floated calcium carbonate (CaCO3) films using ash as raw material. A nylon mesh serves as a growing platform to facilitate the uptake of calcium from the ash, allowing a recovery up to 64% during the synthesis at the interface water/air. The interaction of carbon dioxide (CO2) with water gets carbonic acid (H2CO3) which reacts with calcium ions (Ca2+) to generate a film of CaCO3 on the nylon mesh surface. The CaCO3 films were studied by scanning electron microscopy, and its microstructure and composition were analyzed by Raman spectroscopy, X-ray diffraction and X-ray Fluorescence. Our findings show this technique has a potential for large scale production of highly pure CaCO3 powder. [ABSTRACT FROM AUTHOR]

Lush jungle flagship species, woody bamboos (Poaceae-Bambusoideae) are famed for their synchronous flowering as well as the extensive "bamboo forests" some species can form in tropical or temperate environments. In portions of their natural distribution, Bambusoideae members developed various adaptations to seasonality in environmental parameters, such as frost or seasonal drought. A new taxon, Laobambos calcareus, described here, is extremely novel in showing the first documented case of succulence in bamboos, with its ability to seasonally vary the volume of its stem depending on the quantity of water stored. Anatomical studies presented in this paper document this specificity at the cellular level. Though no flowers or fruits are known yet, unique morphological characteristics along with an investigation of its phylogenetic affinities using molecular data show that this new taxon should belong to a new genus herein described. [ABSTRACT FROM AUTHOR]

Dune is often considered as a degraded ecosystem. Natural vegetation restoration and stable artificial vegetation construction are the basic means restoring dune ecosystem. Based on long-term study of dune ecosystem, by taking into consideration both the philosophical principles of unity of opposites and dynamic change, and related ecological theories, we put forward some ecological relations that should be paid attention to in the study of vegetation assembly from the perspective of the uniqueness of dune ecosystem. We discussed the necessity of coupling relationships of scale-pattern-process and the transformation of synergy-tradeoff relationships, interpreted the importance of distinguishing sand dune stabilized and shifting phases, disturbance and stress, wind erosion and sand burial in the study of vegetation process. We further explored the applied value of niche law or neutral law in the study of dune vegetation process. Finally, we discussed the issues that should be paid attention to in the study of dune vegetation process from the aspects of adaptability to aeolian activities and drought tolerance, physiological and reproductive process, sexual and asexual reproduction of plants. This study would provide theoretical supports for vegetation restoration and stable vegetation construction of dune ecosystem.

Aim: Using the extremophile genus Anabasis, which includes c. 28 succulent, xerophytic C4 species, and is widely distributed in arid regions of Northern Africa, Arabia, and Asia, we investigate biogeographical relationships between the Irano‐Turanian floristic region (ITfr) and its neighboring regions. We test whether the spread of arid and semi‐arid biomes in Eurasia coincides with the biogeography of this droughtadapted genus, and whether the ITfr acted as source area of floristic elements for adjacent regions. Location: Deserts and semi‐deserts of Northern Africa, Mediterranean, Arabia, West and Central Asia. Methods: Four cpDNA markers (rpL16 intron, atpB‐rbcL, trnQ‐rps16, and ndhF‐rpL32 spacers) were sequenced for 58 accessions representing 21 Anabasis species. Phylogenetic relationships and divergence times were inferred using maximum likelihood and a time‐calibrated Bayesian approach. To document the extant distribution of Anabasis, material from 23 herbaria was surveyed resulting in 441 well‐documented collections used for the coding of eight floristic regions. Using this coded data, ancestral range was estimated using “BioGeoBEARS” under the DEC model. Results: Anabasis originated during the Late Miocene and the ancestral range was probably widespread and disjunct between Western Mediterranean and the Irano‐ Turanian regions. Diversification started with two divergence events at the Miocene/Pliocene boundary (5.1 and 4.5 mya) leading to Asian clade I with ITfr origin which is sister to a slightly younger Asian clade II, which originated in the Western ITfr, and a Mediterranean/North African clade with an origin in the Western Mediterranean. Main conclusions: Anabasis did not follow aridification and continuously expanded its distribution area, in fact its probably wide ancestral distribution area seems to have been fragmented during the very Late Miocene and the remnant lineages then expanded into neighboring arid regions. This genus supports the role of the ITfr as source area for xerophytic elements in the Mediterranean and Central Asia. [ABSTRACT FROM AUTHOR]

The aim of this study is to compare the water and photosynthetic characteristics of two xerophilic ecotypes of Atriplex halimus (L.). Seeds collected from two different sites Djelfa and Oran are germinated in controlled greenhouse. After 6 months, the plantlets were treated 21 days with increasing concentrations of abscisic acid (0M, 10-6 M and 10-3 M). The results show that ecotype of Djelfa reduced water loss through transpiration because of high stomatal resistance. Consequently the content of chlorophyll a and b decrease significantly compared to Oran ecotype which show an increase of the osmotic potential and relative water content. Osmotic adjustment to reduce dehydration and maintain a good photosynthesis seems efficient in Oran ecotype.

Understanding the unusual physiological mechanisms that enable drought tolerance in xerophytes will be of considerable benefit because of the potential to identify novel and key genetic elements for future crop improvements. These plants are interesting because they are well-adapted for life in arid zones; Zygophyllum xanthoxylum, for example, is a typical xerophytic shrub that inhabits central Asian deserts, accumulating substantial levels of sodium (Na+) in its succulent leaves while growing in soils that contain very low levels of this ion. The physiological importance of this unusual trait to drought adaptations remains poorly understood, however. Thus, 2-week-old Z. xanthoxylum plants were treated with 50 mM NaCl (Na) for 7 days in this study in order to investigate their drought tolerance, leaf osmotic potential (Ψs) related parameters, anatomical characteristics, and transpiration traits. The results demonstrated that NaCl treatment significantly enhanced both the survivability and durability of Z. xanthoxylum plants under extreme drought conditions. The bulk of the Na+ ions encapsulated in plants was overwhelmingly allocated to leaves rather than roots or stems under drought conditions; thus, compared to the control, significantly more Na+ compared to other solutes such as K+, Ca2+, Cl-, sugars, and proline accumulated in the leaves of NaCl-treated plants and led to a marked decrease (31%) in leaf Ψs. In addition, the accumulation of Na+ ions also resulted in mesophyll cell enlargement and leaf succulence, enabling the additional storage of water; Na+ ions also reduced the rate of water loss by decreasing stomatal density and down-regulating stomatal aperture size. The results of this study demonstrate that Z. xanthoxylum has evolved a notable ability to utilize Na+ ions to lower Ψs, swell its leaves, and decrease stomatal aperture sizes, in order to enable the additional uptake and storage of water and mitigate losses. These distinctive drought adaption characteristics mean that the xerophytic plant Z. xanthoxylum presents a fascinating case study for the potential identification of important and novel genetic elements that could improve crops. This report provides insights on the eco-physiological role of sodium accumulation in xerophytes adapted to extremely arid habitats.

Understanding the unusual physiological mechanisms that enable drought tolerance in xerophytes will be of considerable benefit because of the potential to identify novel and key genetic elements for future crop improvements. These plants are interesting because they are well-adapted for life in arid zones; Zygophyllum xanthoxylum , for example, is a typical xerophytic shrub that inhabits central Asian deserts, accumulating substantial levels of sodium (Na+) in its succulent leaves while growing in soils that contain very low levels of this ion. The physiological importance of this unusual trait to drought adaptations remains poorly understood, however. Thus, 2-week-old Z. xanthoxylum plants were treated with 50 mM NaCl (Na) for 7 days in this study in order to investigate their drought tolerance, leaf osmotic potential (Ψs) related parameters, anatomical characteristics, and transpiration traits. The results demonstrated that NaCl treatment significantly enhanced both the survivability and durability of Z. xanthoxylum plants under extreme drought conditions. The bulk of the Na+ ions encapsulated in plants was overwhelmingly allocated to leaves rather than roots or stems under drought conditions; thus, compared to the control, significantly more Na+ compared to other solutes such as K+, Ca2+, Cl-, sugars, and proline accumulated in the leaves of NaCl-treated plants and led to a marked decrease (31%) in leaf Ψs. In addition, the accumulation of Na+ ions also resulted in mesophyll cell enlargement and leaf succulence, enabling the additional storage of water; Na+ ions also reduced the rate of water loss by decreasing stomatal density and down-regulating stomatal aperture size. The results of this study demonstrate that Z. xanthoxylum has evolved a notable ability to utilize Na+ ions to lower Ψs, swell its leaves, and decrease stomatal aperture sizes, in order to enable the additional uptake and storage of water and mitigate losses. These distinctive drought adaption characteristics mean that the xerophytic plant Z. xanthoxylum presents a fascinating case study for the potential identification of important and novel genetic elements that could improve crops. This report provides insights on the eco-physiological role of sodium accumulation in xerophytes adapted to extremely arid habitats. [ABSTRACT FROM AUTHOR]

Agave is recognized as a low recalcitrant material, which makes it a potential source to obtain nanocellulose. Aqueous dispersions (in water, H 2 O 2 , H 2 O 2 /H 2 SO 4 ) of agave powder were heated at 120 °C under vapor pressure (1 kg/cm 2 ). The resultant materials were observed with an optical microscope (OM), a laser scanning microscope (LSM) to obtain the thickness measurement and a scanning electron microscope (SEM) to observe morphology. Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to obtain the chemical structure. Cellulose nanoplatelets (CNPs) from Agave salmiana were successfully isolated under mild conditions. Physicochemical analysis indicates that lignin was removed in a single step oxidation with hydrogen peroxide in presence of sulfuric acid at low concentration (0.17 M). The CNPs images revealed the presence of entangled cellulose nanofibrils (Ø ≈ 14 nm) along the nanoplatelets (thickness ≈80 nm). [ABSTRACT FROM AUTHOR]

This study was conducted to understand the patterns of plant species richness in the Three Gorges Reservoir after 5 years after 175 m submergence. We hypothesized that hygrophyte and xerophyte species would show different species richness patterns, which was tested by collecting species composition and environmental variable data in 50 m long and 5 m wide transects in the drawdown zone from 145 m to 180 m. Xerophyte species richness (XSR) was highest in the middle of the drawdown zone, whereas hygrophyte species showed a continuous downward trend from 145 m to 180 m. Correlation analyses showed that the flooding period was significantly negatively correlated with the total species richness (TSR), XSR, and hygrophyte species richness (HSR). The TSR and XSR showed a significant positive correlation with soil type and a significant negative correlation with available K. HSR was significantly correlated with soil type and negatively correlated with ammonium N. [ABSTRACT FROM AUTHOR]