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Despite hostile climate in the Kuwait desert, perennial vegetation patches persist but are affected by anthropogenic pressures and need to be conserved or restored to their original state. Our goal was to assess the bacterial community composition and structure in both rhizospheric and bulk (non-rhizospheric) soil samples from protected and unprotected sites of four dominant terrestrial vegetation types in the Kuwaiti desert. The bacterial composition and structure was investigated by Illumina MiSeq sequencing of the 16S rRNA gene. Compared to other desert soils, a relatively high diversity of bacteria was detected in this study. Bacterial sequences were affiliated with 13 phyla, most abundant of which revealed were Actinobacteria, Proteobacteria, Planctomycetes, Acidobacteria, Bacteroidetes and Firmicutes. The bacterial structure also commonly identified as Chloroflexi, Gemmatimonadetes, Saccharibacteria, Chlamydiae, Armantimonadetes, Deinococcus-Thermus and Verrucomicrobia. The analyses revealed that bacterial communities that were dominated by members of the phyla Actinobacteria and Proteobacteria found with higher diversity indices in rhizospheric soils. In addition, samples with high diversity indices as measured by the Chao1 and invsimpson indices were from rhizospheric soils, with some exceptions. The beta diversity indices of samples/habitats assessed via cluster analysis indicated noticeable differences in the bacterial community compositions of the sites. This study demonstrates the effect of protected and unprotected areas with vegetation covers and anthropogenic disturbances on Kuwait desert soil bacterial communities. This study provides the first insights into bacterial communities associated with protected and unprotected areas across the Kuwait desert. This information is essential for evaluating how natural and anthropogenic drivers affect plant-bacteria-soil systems in the Kuwait desert.

Seed viability and germination are key factors in the success of restoration efforts, especially when stored seeds are used. However, the effect of seed storage on germination of most of the native...

Acacia gerrardii is the only native tree species of the Kuwaiti desert ecosystem. However, anthropogenic disturbances and harsh arid climate have contributed towards the disappearance of this keystone species from its habitat. In this study, effects of different seed pretreatments to break dormancy, water entry pathway, and ecology (seasonal timing) of dormancy loss and germination of A. gerrardii were investigated. Effects of mechanical scarification, hot water treatment (30 s, 1, 2, and 5 min), and concentrated acid scarification (10, 20, and 30 min) on germination percentage and rate (time to 50% germination and final germination) were also examined. Pretreatment with mechanical scarification produced the highest germination in the least time and 20 °C, 40% RH with 12 h of light (2370 Lux) were found to provide the best germination environment. Seeds were rapidly aged at 60% RH and 45 or 50 °C to determine longevity, and the results were analyzed using probit analysis. Times taken for viability of A. gerrardii seeds aged at 45 and 50 °C to fall to 50% (p50) were 38.6 and 9.3 days, respectively, and therefore the seeds can be considered to have medium longevity. Experiments to find the water entry pathway in A. gerrardii indicated that the micropyle region was the primary point of water entry into the seed. Seed burial experiments indicated that though seed retention decreased over time, there was no significant decrease in number of viable seeds after 31 weeks. The findings of this study are important to nursery managers, seed banks, and those involved in conservation and restoration activities.

Plant physiological and morphological attributes should be critically evaluated for selecting any species for landscaping projects. The selection of a species should be based on the evaluation of its adaptability, noninvasiveness, growth potential, and performance under the prevailing local arid conditions for their aesthetic looks, soil stabilization, and afforestation values. Chrysopogon zizanoides (Vetiver), is suitable for Kuwait because it can withstand fluctuating temperatures ranging from −14 to 55 °C with unique physical and physiological characteristics. Despite the successful growth performance of Vetiver in landscaping projects mostly in several tropical countries, it has not been utilized and evaluated in the Arabian Gulf region. The objective of the current study was to evaluate the performance of selected ten cultivars of Vetiver (ODV-1, 8, 9, 13, 17, 21, 23, Silent Valley, Urlikal, and Pannimedu) in the deficient soil and environmental conditions of Kuwait in urban landscape at minimal maintenance. It is suggested that based on visual greenery effect and overall growth performance cultivars, Pannimedu, Silent Valley, ODV-13, ODV-8 and ODV-9 can be considered for landscaping projects in Kuwait. To obtain the superior crown volume (which considers height and canopy) cultivar Pannimedu is suggested and to get a bushy growth (considering the number of tillers) cultivar ODV-13 and ODV-8 is found to be suitable.

The genus Acacia Miller is species-rich, and species discrimination is challenging owing to morphological similarities between closely related species. Naming of specimens is particularly difficult in the Middle East, where confusion in taxonomic identification exists within the context of a wider international debate on the generic systematics of Acacia sensu lato. At least five segregate genera for Acacia s.l. have been advocated: Acacia sensu stricto, Vachellia, Senegalia, Acaciella and Mariosousa. Furthermore, identification to species of the only remaining native Acacia s.l. tree in Kuwait is still a matter of controversy. The present study used multilocus chloroplast DNA sequence data analyses following maximum likelihood (ML) and Bayesian approaches to: 1) test the species concepts of Vachellia pachyceras (≡ Acacia pachyceras O.Schwartz) from the Middle East, and Vachellia tortilis (Forssk.) Galasso & Banfi (≡ Acacia tortilis (Forssk.) Hayne) and Vachellia gerrardii (Benth.) P.J.H.Hurter (≡ Acacia gerrardii Benth.) from Kenya, as well as to investigate species divergence times; and 2) identify the only remaining native Acacia s.l. tree in Kuwait (known as the Lonely Tree), as well as other unidentified Acacia s.l. specimens in cultivation. The Bayesian and ML topologies clearly differentiated Vachellia pachyceras, V. tortilis and V. gerrardii, and demonstrated that the three species are distinct. Divergence time estimates using the ML topology suggested that Vachellia gerrardii diverged from a common ancestor no later than the early Pliocene (3.3 Mya), whereas V. pachyceras originated at least 2.0 Mya (Pliocene). The unknown remaining native Acacia s.l. tree in Kuwait and other specimens collected from the nursery were identified as Vachellia pachyceras. These results stress the need to use plastid DNA barcodes complemented by population genetics approaches to address systematic issues in this complex of Acacia s.l. species in the Middle East and the Arabian Peninsula.

Kuwait is a semi-arid region with harsh climatic conditions with poor available soil nutrient essential for the growth of plants. Kuwait’s ecosystem is relatively N-poor ecosystem when compared to the other ecosystems. Biological nitrogen fixation (BNF) is a spontaneous process in which diazotrophic bacteria fixes the atmospheric nitrogen directly in to the bionetwork. At present, there is limited information on free-living and root associated nitrogen-fixing bacteria, their potential to fix nitrogen to aid natural plant communities in the desert of Kuwait. In this study, free-living N2-fixing bacteria were enriched and isolated from the rhizospheric soil of three keystone native plant species of Kuwait; such asRhanterium epapposum, Farsetia aegyptia, andHaloxylon salicornicum. Root associated bacteria were directly isolated from the root nodules ofVachellia pachyceras. In this study, a number of free-living and root associated dizotrophs were isolated from various rhizospheric soils of three native shrubs and root nodules from one tree species. The screened isolates were assessed for nitrogen-fixing ability and identified using Acetylene Reduction Assay (ARA) and 16s rRNA gene sequencing, respectively. Our study successfully identified all the 50 nitrogen-fixers isolated initially and out of that, 78% were confirmed as nitrogen-fixers using ARA. Among the identified nitrogen fixers, the genusRhizobiumis dominant in rhizospheric soil ofRhanterium epapposum, whereasPseudomonasandRhizobiumare dominant in the rhizospheric soil ofFarsetia aegyptia, andHaloxylon salicornicumrespectively. The speciesAgrobacterium tumefaciensis found dominant in the root nodules ofV. pachyceras. The current results indicate that plant species and their rhizospheric effects are important drivers for specificity of microbial diversity in arid soils. To our knowledge, this study is the first investigation of culture-based isolation, molecular identification, and evaluation of N2-fixing ability of diazotrophs from Kuwait desert environment.

This research examined the general soil fungi and AM fungal communities associated with a Lonely Tree species (Vachellia pachyceras) existing in the Sabah Al-Ahmad Natural Reserve located at the Kuwait desert. The goals of the study were to describe the general fungal and AM fungal communities present in the rhizospheric, non-rhizospheric soils and roots of V. pachyceras, respectively, as well as local and non-local V. pachyceras seedlings when grown under standard nursery growing environments. Soil and root samples were analyzed for an array of characteristics including soil physicochemical composition, and culture-independent method termed PCR-cloning, intermediate variable region of rDNA, the large subunit (LSU) and internal transcribed spacer (ITS) region sequence identifications. The results reveal that the fungal phylotypes were classified in four major fungal phyla namely Ascomycota, Basidiomycota, Chytridiomycota, and Zygomycota. The largest assemblage of fungal analyses showed communities dominated by members of the phylum Ascomycota. The assays also revealed a wealth of incertae sedis fungi, mostly affiliated to uncultured fungi from diverse environmental conditions. Striking difference between rhizosphere and bulk soils communities, with more fungal diversities and Operational Taxonomic Units (OTUs) richness associated with both the field and nursery rhizosphere soils. In contrast, a less diverse fungal community was found in the bulk soil samples. The characterization of AM fungi from the root system demonstrated that the most abundant and diversified group belongs to the family Glomeraceae, with the common genus Rhizophagus (5 phylotypes) and another unclassified taxonomic group (5 phylotypes). Despite the harsh climate that prevails in the Kuwait desert, studied roots displayed the existence of considerable number of AM fungal biota. The present work thus provides a baseline of the fungal and mycorrhizal community associated with rhizosphere and non-rhizosphere soils and roots of only surviving V. pachyceras tree from the Kuwaiti desert and seedlings under nursery growing environments.

We investigated the diversity and composition of bacterial communities in rhizospheric and non-rhizospheric bulk soils as well as root nodule bacterial communities of Vachellia pachyceras — the only native tree species existing in the Kuwait desert. Community fingerprinting comparisons and 16S rDNA sequence identifications were used for characterization of the bacterial population using specific primers. The bacterial characterization of soil samples revealed four major phyla: Acidobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. In situ (desert) samples of both rhizospheric and non-rhizospheric bulk soil were dominated by the bacterial phyla Firmicutes and Bacteroidetes, whereas the phylum Betaproteobacteria was present only in non-rhizospheric bulk soil. Ex situ (nursery growing condition) V. pachyceras resulted in restricted bacterial communities dominated by members of a single phylum, Bacteroidetes. Results indicated that the soil organic matter and rhizospheric environments might drive the bacterial community. Despite harsh climatic conditions, data demonstrated that V. pachyceras roots harbor endophytic bacterial populations. Our findings on bacterial community composition and structure have major significance for evaluating how Kuwait’s extreme climatic conditions affect bacterial communities. The baseline data obtained in this study will be useful and assist in formulating strategies in ecological restoration programs, including the application of inoculation technologies.

Organic food production, a dynamic and rapidly growing global activity is still new to Kuwait. Therefore, investigations were conducted during 2006-09 to develop package of cultivation practices for producing organic greenhouse vegetables under Kuwait's environmental conditions. One of the objectives of these investigations was to select a suitable growing substrate for organic greenhouse vegetable production. A number of combinations of vermicompost, cocopeat, sphagnum peatmoss, perlite, farm yard manure and Avicumus were compared with ready- to-use organic substrate for producing tomato, cucumber and capsicum under greenhouse conditions. Vegetative growth parameters (average plant height, number of leaves, chlorophyll index) and fruit yield per plant were used to evaluate various growing substrates. Overall, substrates containing vermicompost, coco peat, perlite and sphagnum peat moss (2:1:1:1 or 1:1:1:1 v/v) produced significantly better growth, yield and quality in tomato, cucumber and capsicum than other substrate combinations and in some cases were better than ready-to-use mixes and conventional soil based growing system. The results of these experiments are discussed in this presentation.

The use of native plants in urban landscape projects conserves natural plant diversity, imparts a natural appeal to the landscape, and requires less water and nutrients than do exotics. Desert annuals like Horwoodia dicksoniae Turril. have seeds with physiological dormancy. We studied the combined effects of dry heat (50°C) and GA3 treatments on germination of Horwoodia dicksoniae. The results showed that the highest germination (88%) occurred when the seeds were subjected to a treatment combination consisting of exposure to dry heat (50°C) for 20 days followed by a treatment with 500 ppm GA3 for 24 hrs. The next best treatment combination (86%) was the combination of 10 days dry heat (50°C) followed by a treatment with 1000 ppm GA3 for 48 hours. This suggested that higher concentration of GA3 could compensate for shorter exposure period to dry heat.

Thirty five ornamental plants were introduced into the Ahmadi Bioremediated Soil Park to screen and closely monitor the growth performance of these new introductions under the local environmental conditions. Out of these 35 plant species, 15 were planted in both bioremediated and agricultural soils to assess their suitability for growing in bioremediated soils. Data on vegetative growth was recorded to assess the performance of newly-introduced plants, whereas, the heat stress was documented of Bauhinia blakeana, where no visible effects of petroleum pollutants on plant growth were observed. Performance of each plant group is discussed separately in the text. Overall, plant survival was 72.73% for all plant groups. Generally, plants that failed to grow in bioremediated soil also did not survive in the agricultural soil, indicating that they were sensitive to heat stress more than the presence of petroleum contaminants in the soil. New plant species that were able to establish and perform satisfactorily wi...

The State of Kuwait has initiated an ambitious national program to establish greenery in 20000 ha of open spaces in inland and coastal areas. Afforestation of intertidal zones with mangrove plants is being considered as a viable option for greening coastal areas. In view of this fact, experimental plantations were established using two ecotypes of Avicennia marina (Bahrain and UAE) and one ecotype of Avicennia germinans (Florida). The study consisted of two 10-year old plantations and two 2-year old plantations. Seedlings established successfully and grew vigorously on some of the locations within the site. Therefore, studies were conducted during 2002-2003 to describe and classify soils that supported maximum mangrove establishment and growth under the harsh arid coastal conditions of Kuwait. For this purpose, eight soil profiles (four each representing areas where seedlings established successfully and grew vigorously and where all seedlings died in the initial stages of establishment) were investigated...

The State of Kuwait is making concerted efforts to enhance greenery along its coastline. This study was conducted during 1999–2002 for identifying key soil factors associated with successful establishment and rapid growth in Avicennia marina. Based on the review of available data, repeated visits to potential sites, on-site assessment and laboratory characterization of soils, five sites (Shuwaikh, Sulaibikhat I, Sulaibikhat II, Doha, and Sabiya) were selected for establishing pilot plantations. Acclimatized seedlings were used to establish these plantations. Periodic data indicated wide variations both in seedling survival and growth both among sites and at different locations within each site. The highest seedling survival (71.0 to 81.2%) was observed in the Doha site and ranged from 16.1 to 78.0% in other sites. In general, seedlings planted along the tidal line showed the survivability and produced greater number of branches than those planted farther away from the tidal line. Postplanting on-site and ...

Increased urbanization, coupled with harsh climatic condition presents difficulties in ornamental plant introduction and selection. Selection of plant materials is crucial in landscaping, as the plants should be well-adapted to the harsh environment. Selection of heat- and drought- tolerant plants is the efficient method for the execution of landscape projects locally especially when they are properly selected, placed and maintained. Several plants were selected to be screened for use in Kuwait's landscaping. The species in this activity were introduced from environments similar to Kuwait. These plants were initiated from seeds and cuttings. According to the nature of the seeds, they were treated to expedite germination and sown using different sowing techniques. Several seeds exhibited high germination percentages. Nevertheless, several seedlings could not thrive when drought stress in summer was introduced.

In the harsh environmental conditions of Kuwait, plants are frequently exposed to high temperatures, low relative humidity and drought. Because water resources available for agriculture are limited, an efficient irrigation strategy is vital for sustainable olive production. In view of these facts, a study to determine the behavior and water requirement of young olive plants under Kuwait's environmental conditions was carried out. The investigation included five cultivars (cvs. Arbequina, Barnea, Coratina, Koroneiki and UC13A6) and three levels of irrigation (50, 75 and 100% of ETc) with brackish water (ECe 5.0 dS m−1). One-year-old grafted plants were used in this study. With the exception of UC13A6, the cultivars showed good adaptation to the harsh weather conditions in Kuwait and to brackish water irrigation during the first 18 months after the beginning of the irrigation treatments. Indeed, they showed good height and shoot growth, with cultivars Barnea, Arbequina and Coratina showing the highest value...