scholarly journals Morfoanatomía del tallo con crecimiento secundario de especies de Jatropha (Euphorbiaceae) nativas de la Región Chaqueña Argentina y su relación con el ambiente

2021 ◽  
Vol 9 (1) ◽  
pp. 75-94
Author(s):  
Valeria Mansilla ◽  
Alejandra Malbrán Barros ◽  
Verónica A. Cabrera ◽  
Marisa Matesevach

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.

2019 ◽  
Vol 11 (23) ◽  
pp. 6572 ◽  
Author(s):  
Eleonora Bottani ◽  
Letizia Tebaldi ◽  
Andrea Volpi

As never before, there is nowadays the will to consider alternative energy sources from renewable and waste materials so as to preserve planet and society. One of the possible elements suitable for this purpose is every day in our houses: Coffee. Or rather, spent coffee grounds. Indeed, many studies in recent years have addressed its potential exploitation, especially for biodiesel production; recent works also pointed out its possible thermal valorization for industrial processes. In light of this, this paper proposes a new sustainable use of spent coffee grounds, converted into combustible pellets; this source can then be used not only for industrial heaters, but also for public or private buildings. To this end, a feasibility study of a pellet production plant fed by waste collected by vending companies operating in the North of Italy is developed, including the logistic model supported by an Information and Communication Technology (ICT) system to help gather spent coffee grounds from the different companies and collect them into the pellet production facility.


2019 ◽  
Vol 45 (1) ◽  
pp. 75-84
Author(s):  
Issam Touhami ◽  
Ali El khorchani ◽  
Zouheir Nasr ◽  
Mohamed tahar Elaieb ◽  
Touhami Rzigui ◽  
...  

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 425
Author(s):  
Rodrigue Vivien Cao Diogo ◽  
Luc Hippolyte Dossa ◽  
Sèyi Fridaïus Ulrich Vanvanhossou ◽  
Badirou Dine Abdoulaye ◽  
Kossi Hélliot Dosseh ◽  
...  

The sustainable use of rangelands in pastoral areas requires the inclusion of all stakeholders to develop sound management strategies. However, the role of these actors in the sustainable management of natural resources is still poorly understood. The present study aims to (i) assess the perception of farmers and herders of the risks and opportunities of transhumance on rangeland resource use and management, and to (ii) generate useful knowledge for the design and implementation of policies that favor the coexistence of these actors and reduce competition over rangeland resources use in Benin. To this end, interviews were conducted with 240 crop farmers and herders using a semi-structured questionnaire in two contrasting agroecological zones in the northern (Kandi) and the southern (Kétou) part of the country. Among the respondents, 64% of farmers in the North were agro-pastoralists (owning 10.6 ha of land and 10.7 cattle) and 36% were herders (keeping 45.8 cattle and cultivating about 3.7 ha of land). They perceived that communal rangelands were entirely degraded. In the South, 36% of respondents were agro-pastoralists (with 0.3 cattle and farming 4 ha of land) and 64% cattle herders (raising 45.3 cattle and farming 0.9 ha of land only). Of the herders, 50% kept cattle for more than 20 years, while agro-pastoralists had no previous experience in cattle herding. Cultivation practices among crop farmers, such as high use of mineral fertilization (23.8%) and bush fires for land clearing (22.5%), were reported in Kandi (North) and Kétou (South) as factors that might contribute to land degradation. However, these farmers perceived transhumance as a threat to the sustainable use of natural resources. In contrast, herders perceived transhumance as an opportunity to valorize unused land and increase the availability of manure to cropland. The prevalent negative attitude of crop farmers regarding transhumant herders increases the vulnerability of cattle herding in both regions. There is an urgent need of raising awareness concerning the mutual benefits provided by the coexistence of crop farmers with herders to promote participative rangeland management strategies. This may contribute towards coping with the current challenges of food insecurity and increasing climate variability as well as to reducing recurrent conflicts in the region.


2021 ◽  
Vol 9 (7) ◽  
pp. 1359
Author(s):  
Elisa Bona ◽  
Nadia Massa ◽  
Omrane Toumatia ◽  
Giorgia Novello ◽  
Patrizia Cesaro ◽  
...  

Algeria is the largest country in Africa characterized by semi-arid and arid sites, located in the North, and hypersaline zones in the center and South of the country. Several autochthonous plants are well known as medicinal plants, having in common tolerance to aridity, drought and salinity. In their natural environment, they live with a great amount of microbial species that altogether are indicated as plant microbiota, while the plants are now viewed as a “holobiont”. In this work, the microbiota of the soil associated to the roots of fourteen economically relevant autochthonous plants from Algeria have been characterized by an innovative metagenomic approach with a dual purpose: (i) to deepen the knowledge of the arid and semi-arid environment and (ii) to characterize the composition of bacterial communities associated with indigenous plants with a strong economic/commercial interest, in order to make possible the improvement of their cultivation. The results presented in this work highlighted specific signatures which are mainly determined by climatic zone and soil properties more than by the plant species.


2019 ◽  
Vol 32 ◽  
pp. 33-46
Author(s):  
Ammar M.S. Al-Helli ◽  
Amjad K. Resen ◽  
Atheer H. Ali

The study was conducted in the Euphrates river in Al-Samawa city at two stations during the period from October 2016 till September 2017. The first station (north station) was Al-Majd township (45°12'49.2"E, 31°22'14.9"N), and the second station (south station) was Al-Zaier region (45°20'21.4"E, 31°18'54.4"N). Some ecological factors were monthly recorded at the stations of the current study, including water temperature, salinity, dissolved oxygen, pH, transparency, the speed of water flow, BOD5 and total hardness. All factors except total hardness have not significant differences between two stations, The hardness in the north station showed higher (844-1475) mg.l-1 than south station (655-1250) mg.l-1. Fishes were collected by gill nets, cast net, hook and line, hand net and electro-fishing. A total of 4260 fish specimens were collected which belong to 24 species and 10 families, 17 species of them were native species whereas seven of them were alien species. The most abundant species was blue tilapia Oreochromis aureus constituted 26.84% of the total caught of a north station, The value of the dominance index (D3) in north station was 62.57%, while the most abundant species in south station was Prussian carp Carassius auratus constituted 27.14% of the total caught, The value of the dominance index (D3) in the south station was 56.42%.


<em>Abstract.</em>—From its headwaters in the Rocky Mountains, the Platte River drains 230,362 km<sup>2</sup> in Colorado, Wyoming, and Nebraska. The Platte River is formed by the confluence of the North Platte and South Platte near the city of North Platte, Nebraska, and receives additional flow from the Loup and Elkhorn rivers that drain the Sand Hills region of Nebraska. Water diversions for mining and irrigation began in the 1840s in Colorado and Wyoming, and irrigation diversions in Nebraska began in the 1850s. Construction of dams for control of river flows commenced on the North Platte River in Wyoming in 1904. Additional dams and diversions in the North Platte, South Platte, and Platte rivers have extensively modified natural flow patterns and caused interruptions of flows. Pollution, from mining, industrial, municipal, and agricultural sources, and introductions of 24 nonnative species have also taken their toll. Fishes of the basin were little studied before changes in land use, pollution, and introduction of exotic species began. The current fish fauna totals approximately 100 species from 20 families. Native species richness declines westward, but some species find refugia in western headwaters streams. Declines in 26 native species has led to their being listing as species of concern by one or more basin states.


2018 ◽  
Vol 22 (6) ◽  
pp. 3275-3294 ◽  
Author(s):  
Irina Y. Petrova ◽  
Chiel C. van Heerwaarden ◽  
Cathy Hohenegger ◽  
Françoise Guichard

Abstract. The magnitude and sign of soil moisture–precipitation coupling (SMPC) is investigated using a probability-based approach and 10 years of daily microwave satellite data across North Africa at a 1∘ horizontal scale. Specifically, the co-existence and co-variability of spatial (i.e. using soil moisture gradients) and temporal (i.e. using soil moisture anomaly) soil moisture effects on afternoon rainfall is explored. The analysis shows that in the semi-arid environment of the Sahel, the negative spatial and the negative temporal coupling relationships do not only co-exist, but are also dependent on one another. Hence, if afternoon rain falls over temporally drier soils, it is likely to be surrounded by a wetter environment. Two regions are identified as SMPC “hot spots”. These are the south-western part of the domain (7–15∘ N, 10∘ W–7∘ E), with the most robust negative SMPC signal, and the South Sudanese region (5–13∘ N, 24–34∘ E). The sign and significance of the coupling in the latter region is found to be largely modulated by the presence of wetlands and is susceptible to the number of long-lived propagating convective systems. The presence of wetlands and an irrigated land area is found to account for about 30 % of strong and significant spatial SMPC in the North African domain. This study provides the first insight into regional variability of SMPC in North Africa, and supports the potential relevance of mechanisms associated with enhanced sensible heat flux and mesoscale variability in surface soil moisture for deep convection development.


Author(s):  
Carlo Nike Bianchi ◽  
Francesco Caroli ◽  
Paolo Guidetti ◽  
Carla Morri

Global warming is facilitating the poleward range expansion of plant and animal species. In the Mediterranean Sea, the concurrent temperature increase and abundance of (sub)tropical non-indigenous species (NIS) is leading to the so-called ‘tropicalization’ of the Mediterranean Sea, which is dramatically evident in the south-eastern sectors of the basin. At the same time, the colder north-western sectors of the basin have been said to undergo a process of ‘meridionalization’, that is the establishment of warm-water native species (WWN) previously restricted to the southern sectors. The Gulf of Genoa (Ligurian Sea) is the north-western reach for southern species of whatever origin in the Mediterranean. Recent (up to 2015) observations of NIS and WWN by diving have been collated to update previous similar inventories. In addition, the relative occurrences of both groups of southern species have been monitored by snorkelling between 2009 and 2015 in shallow rocky reefs at Genoa, and compared with the trend in air and sea surface temperatures. A total of 20 southern species (11 NIS and 9 WWN) was found. Two WWN (the zebra seabream Diplodus cervinus and the parrotfish Sparisoma cretense) and three NIS (the SW Atlantic sponge Paraleucilla magna, the Red Sea polychaete Branchiomma luctuosum, and the amphi-American and amphi-Atlantic crab Percnon gibbesi) are new records for the Ligurian Sea, whereas juveniles of the Indo-Pacific bluespotted cornetfish Fistularia commersonii have been found for the first time. While temperature has kept on increasing for the whole period, with 2014 and 2015 being the warmest years since at least 1950, the number of WWN increased linearly, that of NIS increased exponentially, contradicting the idea of meridionalization and supporting that of tropicalization even in the northern sectors of the Mediterranean basin.


Author(s):  
J. R. Lumby

Comparison of the conceptions which have hitherto been held in regard to the hydrography of the English Channel with those which are offered as a result of the recent activities of the Atlantic Slope Committee, shows that a difference exists which, in the writer's opinion, lies in the interpretation of the material, rather than in the fundamental differences in the material itself. For example, it is stated that the physical character of the water in the English Channel is conditioned, especially in the summer months, by that of the North Sea water rather than by that of the Atlantic water. “En plein été, en août, les eaux chaudes de la mer du Nord affluent dans la Manche.” A similar regimen is suggested for the waters of the Irish Sea, which are said to be derived from the northward. Carruthers shows that the normal water movement in the eastern part of the English Channel is through Dover Straits into the Southern Bight, this movement appearing to be more persistent along the bottom than on the surface. Furthermore, one of the two months in which reversal of this direction appears least likely to occur is August.


Parasitology ◽  
2020 ◽  
Vol 147 (6) ◽  
pp. 706-714 ◽  
Author(s):  
John Rhidian Thomas ◽  
Chloe V. Robinson ◽  
Agata Mrugała ◽  
Amy R. Ellison ◽  
Emily Matthews ◽  
...  

AbstractThe spread of invasive, non-native species is a key threat to biodiversity. Parasites can play a significant role by influencing their invasive host's survival or behaviour, which can subsequently alter invasion dynamics. The North American signal crayfish (Pacifastacus leniusculus) is a known carrier of Aphanomyces astaci, an oomycete pathogen that is the causative agent of crayfish plague and fatal to European crayfish species, whereas North American species are considered to be largely resistant. There is some evidence, however, that North American species, can also succumb to crayfish plague, though how A. astaci affects such ‘reservoir hosts’ is rarely considered. Here, we tested the impact of A. astaci infection on signal crayfish, by assessing juvenile survival and adult behaviour following exposure to A. astaci zoospores. Juvenile signal crayfish suffered high mortality 4-weeks post-hatching, but not as older juveniles. Furthermore, adult signal crayfish with high-infection levels displayed altered behaviours, being less likely to leave the water, explore terrestrial areas and exhibit escape responses. Overall, we reveal that A. astaci infection affects signal crayfish to a much greater extent than previously considered, which may not only have direct consequences for invasions, but could substantially affect commercially harvested signal crayfish stocks worldwide.


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