Photosystem II and cellular membrane stability evaluation in hexaploid wheat seedlings under salt stress conditions

Salinity limits crop production in large areas of the world. The application of in vitro Photosystem II (PS‐II) activity measurements to screen hexaploid wheat (Triticum aestivum, L.) genotypes for NaCl tolerance has been investigated by comparing their responses under stress and control (no added NaCl) conditions. One of the four cultivars used in the study was ‘Kharchia’ known for its high salt tolerance. Wheat seedlings were grown hydroponically in environmental chambers and treated with a range of NaCl concentrations (0.034 M, 0.17 M, 0.68 M, or 3.42 M) over a 1, 3, and 5‐day period. The salt treatments were started in the appropriate time so that they were all ten‐day‐old during harvest. Cellular membrane stability (CMS) as measured by a conductivity method and PS‐II activity values were affected adversely by NaCl concentration and duration of treatment. Both methods clearly distinguish between salt‐sensitive and salt‐tolerant genotypes. Statistical analysis showed that PS‐II activity and CMS measurements are well correlated (r=0.7589) suggesting that PS‐II activity would be used as an additional screening method besides CMS to evaluate salt tolerance of wheat.     

Gully incision as a key factor in desertification in an arid environment, the Negev highlands, Israel

Gully incision has been eroding the alluvial sediments and loess soils deposited and developed along the valleys in the arid and semiarid regions of Israel. This phenomenon is critical in the arid regions of the Negev Highlands where the agricultural fields, the main floral biomass and the areas which have the highest grazing value, are limited to narrow valleys filled with redeposited loessial sediments. The headcut migration and gully development in the region were studied between 1990 and 2001 in three representative drainage basins (Zipporim, Revivim and Sekher). During flood events, the runoff penetrates the alluvial cover of the valleys, forming vertical headcuts, which gradually retreat up the valley. The runoff is channeled into narrow gullies, preventing the floodwater from spreading over the whole width of the valley. The change in irrigation efficiency along the valleys is reflected in a sharp estimated drop of 70–90% in the floral biomass, causing the reduction of the range value by 83–99%. During the monitoring time interval (1990–2001), the linear gully retreat in the study area ranged between 12.3 and 250 m an average rate of 1.12–22.7 m year^{− 1} for each gully head. The process is accompanied by erosion of soil, which has high agricultural and range value. The total soil losses in these sites ranged between 800 and 9000 m³ at an average rate of 81–818 m³ year^{− 1} for each gully head, which is equivalent to 121–1227 Mg year^{− 1}. During the monitoring period, approximately 0.11–0.87 ha of land lost its agricultural and range value in each basin under study, at an average rate of 0.01–0.079 ha year^{− 1}. Since the Byzantine period (1400 BP), approximately 6.5 ha, which is 10% of the land that had high agricultural and range value in the Zipporim valley, lost its value due to gully erosion. No recovery effects of the gully channels were found in the nearby region. The soil erosion is generated by a long-term natural dynamic change in the soil / rock ratio evolving within the drainage basins through time since the termination of the last glacial phase. The loessic sediments, originally deposited within the drainage basins during the late Pleistocene glacial stage, are being removed under the present Holocene climate in several erosion stages. This ongoing phenomenon is causing degradation of soil and biomass and is severely reducing the agricultural and range potential of the region. These parameters indicate that an ongoing process of desertification is active in the arid environment of the Negev Highlands, and is advancing in proportion to the headcut retreat rates in the region. The soil erosion and headcut retreat have been active in the Negev Highlands for the last few millennia. If these processes continue in the future, the Negev Highlands region will lose its agricultural potential within a few millennia. However, the fact that the ancient inhabitants of the region implemented successful long-term land conservation techniques already 3000 years ago, implies that a sustainable land management policy can be adapted to the Negev Highlands, as well as to other semi-arid regions in the Middle East.     

Boron stress,oxidative damage and antioxidant protection in potato cultivars (Solanum tuberosum L.)

Six potato cultivars grown in Turkey in boron-prone areas and differing in their tolerance towards high boron were studied to reveal whether boron causes oxidative stress. To assess stress level, chlorophyll fluorescence and growth parameters were measured. Oxidative damage was assessed as malondialdehyde level, and antioxidant protection was evaluated as ascorbate (AA), dehydroascorbate, reduced glutathione (GSH) and oxidized glutathione amounts and superoxide dismutase, catalase, ascorbate peroxidase (APX) and glutathione reductase (GR) activities. High boron stress affected photosynthesis negatively in a threshold-dependent manner and inhibited growth. No pronounced changes in oxidation of lipids occurred in any cultivar. Activation of APX suggested the involvement of an ascorbic acid–reduced glutathione cycle in the protection against oxidative stress caused by high boron. Efficient work of this antioxidant system was probably hindered by boron complexation with NAD(P)⁺/NAD(P)H and resulted in the inhibition of GR and a decrease in AA and GSH. Hence, oxidative stress associated with high boron is a secondary component of boron toxicity which arises from metabolic changes caused by boron interference with major metabolites. Potato cultivars tolerate excess boron stress well and show damage only in very high boron concentrations. The potato cvs best suited for high boron soils/breeding purposes are cvs Van Gogh and Agria.

Abbreviations: AA: ascorbic acid; APX: ascorbate peroxidase; CAT: catalase; DHA: dehydroascorbic acid; DHAR: dehydroascorbate reductase; DTNB: 5; 5′-dithiobis-2-nitrobenzoic acid; DTT: dithiotreitol; F_v/F_m: photosynthetic efficiency at the dark-adapted state; GR: glutathione reductase; GSH: reduced glutathione; GSSG: oxidized glutathione; MDA: malondialdehyde; ROS: reactive oxygen species; SOD: superoxide dismutase; TCA: trichloroacetic acid     

An ethnobotanical survey of the Gollak region, Kosovo

An ethnobotanical field study focused on traditional uses of medicinal plants, wild food plants, and mushrooms was conducted in 37 villages in the Gollak region of eastern Kosovo. Interviews with 66 elderly informants were conducted using standard ethnobotanical methods. The uses of 92 vascular plants and 6 mushrooms species belonging to 47 different families were recorded. Mainly infusions and decoctions were quoted as folk medicinal preparations and the most commonly quoted plant medicinal uses referred to diseases of the respiratory system, skin, and gastrointestinal tract. Comparison of the collected data with the ethnobotanical findings of previously conducted studies in the surrounding Western Balkan areas showed that, even if more than the half of Gollak’s wild botanical genera quoted as medicines used are the same in Serbia and in Northern Albania, commonalities between the actual medicinal plant applications recorded in the present study and those reported for the other areas are extremely scarce. This may confirm the richness of the bio-cultural heritage of the Western Balkan region and the urgent need to conduct cross-cultural comparative field ethnobiological studies.     

Ethnobotany of rural and urban Albanians and Serbs in the Anadrini region,Kosovo

Genetic Resources and Crop Evolution - Ethnobotanical studies in South-Eastern Europe have gained several scholars’ and stakeholders’ interest since they are considered crucial for...     

Omphalocele in a foal

An omphalocele was detected at birth in a male Arabian foal. The mass contained small intestine and after releasing a constricting band at the body wall, the contents slipped easily back into the abdomen. On the outside was the hairless pink membrane. The interior, now empty of small intestine, contained the umbilical arteries and vein, and a large urachus that extended from the bladder to the opening at the extremity of the mass. Six days after corrective surgery the foal was sent home and remained healthy.     

LTSER platforms as a place-based transdisciplinary research infrastructure: learning landscape approach through evaluation

Landscape Ecology - Place-based transdisciplinary research involves multiple academic disciplines and non-academic actors. Long-Term Socio-Ecological Research (LTSER) platform is one concept with ~...     

Traditional medicinal plant knowledge among Albanians, Macedonians and Gorani in the Sharr Mountains (Republic of Macedonia)

A medico-ethnobotanical study was conducted among Albanians, Macedonians, and Gorani in forty-one villages located in the Sharr Mountains in western Macedonia. The survey was conducted by interviewing local people of each community about the medicinal plants and their uses and properties. Seventy-six mainly wild taxa were found to represent the remaining folk medical heritage of the area. The large majority of the recorded plants are used in form of teas, and mainly for minor dysfunctions of the respiratory system. Among the findings, the uncommon uses of Ballota nigra L. (leaves) tea as a digestive, Convolvulus arvensis L. (aerial parts) tea against hypertension, Chenopodium urbicum L. leaves (topically applied) for treating hemorrhoids, and Cornus sanguine L. (leaves and fruits) tea against stomachaches could be of interest for further phytopharmacological studies. A significant portion of study participants raised concerns regarding the possibility of over-exploitation of a few species due to collecting practices serving both local and outside (pharmaceutical) markets. Most of the uses reported by Macedonians and Gorani were also recorded among Albanians, while a significant portion of plants quoted by Orthodox Macedonians showed an idiosyncratic use. This may be explained by the fact that the Gorani lived very close to the Albanian communities in the study area over the last century, with marriages between the two communities being commonplace and facilitated by their shared (Muslim) faith.     

Changes in total protein profiles of barley cultivars in response to toxic boron concentration

In this study, ten‐day‐old seedlings of barley {Hordeum vulgare L. cultivar Anadolu [boron (B)‐tolerant] and Hamidiye (B‐sensitive)} were used. Boron‐treated plants were grown on H₃BO₃ solution (final concentration of 10 mM) for five days. Control plants received no B treatment during this period. Total protein patterns were obtained by analysis of total protein extract from root and leaf tissues of control and B‐treated plants using two‐dimensional gel electrophoresis followed by silver staining. The protein profile of B‐treated seedlings of each cultivar was compared to the profile of control (no stress treatment) plants of the same cultivar. Silver‐stained gels showed that B stress caused increases or decreases in a number of proteins in root and leaf tissues. Moreover, as a result of B treatment, one newly synthesized protein with relative molecular weight (M_r) of 35.0 kDa was detected in root profile of the tolerant cultivar. This protein failed to show up in root profile of the B‐treated sensitive cultivar. Three proteins were quantitatively increased in B‐treated root profile of both cultivars. Following B treatment, three proteins were increased in root profile of the tolerant cultivar, but were not changed in the sensitive one. In leaf tissues, however, there were remarkable changes in total protein profiles after B treatment, relative to the control. Following B treatment, in leaf tissues, at least seven proteins were increased in amount in tolerant cultivar but were unchanged in the susceptible one. In tolerant and sensitive cultivars, amounts of two proteins were increased in B‐treated plants, relative to control seedlings. In addition, four proteins (M_r:29, 58, 58, and 22 kDa) were unchanged in control and B‐treated seedlings of the tolerant cultivar. In the susceptible cultivar however, among these four proteins, the first one (M_r:29) was very much reduced and the others (M_r: 58, 58, and 22 kDa) were completely lost in B‐treated seedlings. Moreover, following B treatment, a set of high‐molecular‐weight proteins was quantitatively decreased in the susceptible cultivar but was unchanged in the tolerant cultivar. These results indicate that in barley, certain proteins may be involved in tolerance to B toxicity. In this study, changes in polypeptide composition as a result of B toxic concentration in leaf tissues were more abundant than in roots. Therefore, it is suggested that these changes, especially at shoot level may form the basis of the tolerance mechanism to B toxicity.     

Timing of fruit removal affects concurrent vegetative growth and subsequent return bloom and yield in olive (Olea europaea L.)

Olive (Olea europaea) demonstrates a high tendency toward alternate fruit production, with significant negative consequences on the industry. Fruit load is one of the main cause-and-effect factors in the phenomenon of biennial bearing, often disrupting the balance between reproductive and vegetative processes. The objectives of the present study were to identify the time range during which heavy fruit load reversibly interrupts the reproductive processes of the following year. The linkage between timing of fruit removal, vegetative growth, return bloom, and fruit yield was studied. Complete fruit removal in cv. Coratina until about 120 days after full bloom (August 15) caused an immediate resumption of vegetative growth. The new shoots grew to twice the length of those on trees that underwent later fruit removal. Moreover, a full return bloom, corresponding with high subsequent yields, was obtained by early fruit removal, while poor or no bloom developed on late-defruited or control trees. Thus, the critical time to affect flowering and subsequent fruiting in the following year by fruit thinning occurs in olive trees even weeks after pit hardening—much later than previously suggested. Furthermore, the data indicate that flowering-site limitation, due to insufficient or immature vegetative growth during the On-year, is a primary factor inducing alternate bearing in olive.