The date palm can grow in desert areas using high salinity groundwater by increasing the number of irrigation cycles. A field experiment was carried out on date palm cv. Sayer offshoots grown in sandy saline soil during the 2017 and 2018 growing seasons. The outcomes demonstrated that the application of saline (10 dS m–1) groundwater every four days increased plant height, number of new leaves, total chlorophyll, and relative water content. In turn, the hydrogen peroxide, malondialdehyde, and electrolyte leakage were reduced. Also, the effect of this treatment improved the growth of the plants, thus reduced the absorption of sodium, chloride, and increased potassium, then decreased the Na/K ratio. Cluster analysis showed two distinct cluster groups. In the first group, the dissimilarity between the treatments is illustrated by the influence of freshwater. While the second group showed the similarity between the treatments of four days and every week in the subgroup. Whereas treatment of two weeks duration shows the most detrimental effect on growth indices and chemical properties of offshoots. The utilization of saline groundwater in the water system of the date palm is the best option among the solutions possible in the current conditions of drought and thermal retention.
The inputs of As in forest ecosystems have declined since the eighties when the higher concentrations of that metalloid were observed due to industrial activities. The As inputs to the forest floor include throughfall and litterfall where dry deposition is an appreciable percentage. This is manifested by the higher As concentration in older needles of conifers and the enrichment of throughfall relative to the bulk deposition. The throughfall and the forest floor convert the inorganic As into methylated organic As and in this way reduce its toxicity. In unpolluted forests the vast percentage of As is retained in soils because the oxides of Fe and Al are very efficient holders. In polluted forested soils the As can become mobile and enrich the surface runoff waters approaching even the threshold value set by the World Health Organization. For this reason forest soils with high concentration of As due to former high loads should be monitored.
Barandabhar Corridor Forest (BCF), the biologically functional corridor, is surrounded by the large human settlements that exploit the corridor where large mammals such as tigers, leopards and their prey such as ungulates, primates, and rhinoceros occur. This study aimed to evaluate major determinants that affect the distribution of large mammals in BCF, Chitwan, Nepal that connects the biologically significant Chitwan National Park with the Mahabharat range. The status and distribution of large mammals along the habitat and disturbance gradients were determined by using 29 line transects (mean length = 4.59 ± 0.38 km) that covered a linear distance of 133.13 km. The chital were the most abundant mammals (density per km2 (D) = 8.9095 ± 1.4570 and encounter rate per km (ER) = 1.49) followed by rhesus monkey (D = 38.896 ± 16.013, ER = 0.28), wild boar (D = 14.814 ± 3.57, ER = 0.62), northern red muntjac (D = 9.6566 ± 2.9514, ER = 0.62) and sambar (D = 5.392 ± 2.319, ER = 0.38). Similarly, the sign encounter rate of tiger and leopard was 0.435 and 0.503 respectively. Habitat types, human disturbances, and coverage of invasive and alien plant species (IAPs) played a key role in the distribution of large mammals. The occurrence of mammals was low nearer to the settlements and roads and coverage of IAPs and more nearer to the water resources. However, degradation of foraging grounds such as grasslands by succession and invasion of alien plant species added more threats to the survival of large mammals. Therefore, such a situation can be improved through the scientific management of forests and grasslands.
Sideritis incana, Stachys ocymastrum, and Thymus fontanesii are medicinal plants belonging to the Lamiaceae family and occurring in semi-arid lands in northern Algeria and in many other countries along the Mediterranean coastline. Despite the ecological and economic interests and also the questionable future these species may meet in their natural habitats, various aspects of their seed biology have not been recognised to this date. This study was intended for in situ conservation of these plants. The problem investigated was the germination response of seeds to different water potential levels attained with using different amounts of polyethylene glycol (PEG6000) (0, –0.03, –0.07, –0.2, –0.5, –1 and –1.6 MPa). In this way, the appropriate conditions and the threshold tolerance of seed germination against water stress were assessed. Seeds of the three species lacked primary/innate dormancy and they germinated abundant and fast in distilled water (S. incana – 65%; S. ocymastrum – 60% and T. fontanseii – 90%). Small seeds of T. fontanesii tolerated more water stress and germinated under up to –1 MPa (–10 bars). Large seeds of S. incana and S. ocymastrum, however, were more sensitive to the drought stress and germinated only under –0.5 MPa (–5 bars). Moreover, more studied parameters were found developing negative reponse under rising drought stress, such as postponed triggering of seed germination, decreased germination velocity and prolonged germination duration, as well as the average time of germination. Therefore, these three plants appear to postpone their establishment until arrival of conditions promising for germination, including sufficient rainfall.
Some obstacles are associated with in vitro propagation of date palm, such as explant tissue browning, slow callus growth and development, low organogenesis and multiplication efficiency, and frequent tissue vitrification. This investigation studied the effect of five types of gelling agents (Danish Agar, Cero Agar Type 8952, Chile Agar, Gerlite Food Grade, and Agar-Agar.) on in vitro regeneration and bud multiplication of Phoenix dactylifera L. cv. Showathy. The results showed that the highest percentages of callus producing buds and average bud formation (77.78%, 11.5 buds, and 72.23%, 10.9 buds) were obtained in response to 7 g l–1 Danish Agar and Cero Agar Type 8952, respectively. A decrease in browning percentage was observed in tissues cultured in the medium gelled with Danish Agar. Observations showed that Danish Agar and Cero Agar Type 8952 eliminated also shoot vitrification. Compared with other treatments, the total amount of phenolic compounds was significantly reduced to 0.79 and 0.82 mg GAE/g in buds cultured in the media gelled with Danish Agar and Cero Agar Type 8952, respectively. The macronutrient phosphor, calcium, sodium, and micronutrient boron and copper significantly increased in the in vitro shoots regenerated on the media gelled with Danish Agar and Cero Agar Type 8952.
Foliar fertilization is one of the crucial ways for continued cultivation of date palm, obtaining the best results of growth and production, in addition to the possibility to reduce damage from abiotic stress. Although subjected date palm to an annual fertilization program, it faces some challenges, including low soil availability for nutrients, dryness of the soil surface, low root activity in the breeding period, soil alkalinity, as well as water scarcity in areas of cultivation, and symptoms of deficiency of some elements. This review attempts to shed light on the importance of using leaf fertilization, demonstrating the successful technique and positive results, and proving the ability of date palm cells to absorb nutrients, similar to other trees, and interact with chemical and biological fertilizers. Besides, the leaflet’s possibility of absorbing various nutrients, chelated iron, biostimulants, antioxidants, and nano-fertilization, are presented.
The frequently used term ecology is currently interpreted in various ways. This scientific discipline has undergone relatively dynamic development since its inception, and its character is still widening and changing. Therefore, in this contribution we attempt to briefly summarize the subject and contents of current ecology, as well as to propose its more systemic and comprehensive definition. We try to enhance its present definitions especially by putting emphasis on the dynamics of nature (the dynamics of natural processes). We define current ecology as the science dealing with the structure, dynamics and functions of nature including evolution, where structure involves the distribution and abundance of individual organisms, habitats and ecosystems; dynamics include all the aspects of their life trajectories and cycles, including growth, development, reproduction or renewal, interactions and their changes, the cycling of matter, flows of energy and information and their transformations; and functions involve the properties, traits and niches of individual organisms and species in an ecosystem, as well as the properties and niches of ecosystems in the landscape, ecoregion or in the whole Earth system.
The present study was based on the idea of a pheromone trap barrier with alternating dispensers releasing different pheromone mixtures that affect males and females differently. We tested the possibility of increasing the catch efficacy of pheromone trap barriers by altering the pheromone mixture with low levels of cis-Verbenol (cV, targeting males, BM), the mixture with high levels of cV (targeting females, BF) and the pheromone mixture with intermediate levels of cV (SL). In addition, we were interested in lowering the dispersion of attracted bark beetles, especially males, which reduces the risk of attack on trees in the surroundings. Significant highest absolute and relative catch was found in the catch of the combination BM–BF, which was 2.2-fold higher than the catch of the control barrier treated with commercial IT Ecolure baits (Fytofarm, Slovakia). At the same time, the lowest dispersal in the surroundings of the barrier with the combination BM–BF was found, which was 2.5-fold lower than in the control barrier. The performance of the BM–BF combination of mixtures was proved in a field trial experiment where the total season catch of the part of the barrier treated with BM–BF dispensers caught 1.5-fold more beetles during the season than the control part treated with IT Ecolure dispensers. Furthermore, the results confirm that the performance of the combination of low levels of cV (targeting males) and high levels of cV (targeting females) is complemented by the desired reduced dispersion around the barrier, which reduces the risk of attack on trees in the surroundings.
The main goal of this study was to evaluate the impact of the invasive common milkweed (Asclepias syriaca L.) on soil nematode communities. The research was carried out in 2018 and 2019 in an ecosystem of permanent grassland in the basin of the Laborec River in land registries of Drahňov, a Vojany village in southeastern Slovakia. The ecosystem contained a total of 64 species of free-living and parasitic nematodes. The most prevalent trophic groups were bacterial feeders (Acrobeloides nanus), followed by plant parasites (Helicotylenchus digonicus and Pratylenchus pratensis), fungal feeders (Aphelenchus avenae), and omnivores (Eudorylaimus carteri). The number of nematode species, the composition of trophic groups and the structure of communities in areas with invasive plants were similar to those in areas with native vegetation during the two years of observation.