Plant exposure to glyphosate-based herbicides and how this might alter plant physiological and structural processes

Chemical weed control is essential to ensure high levels of productivity in agricultural areas, and glyphosate-based herbicides (GBHs) are the most widely used herbicides at a global scale. GBHs inhibit the 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPS) enzyme, which impairs the shikimate pathway and often leads to plant death. However, indirect effects of GBHs on plant physiology can also lead to plant death. The objectives of this review are to discuss the biochemical, physiological and structural changes GBH application produces in plant species, in addition to inhibiting EPSPS (EC 2.5.1.19), and to reveal how these changes contribute to plant death. We conclude that GBHs promote plant death not only because of EPSPS inhibition but also due to biochemical, physiological and structural changes. Some changes are recurrent and can be used as biomarkers of GBH sensitivity, which can contribute to future works that monitor the presence of these herbicides in plant communities near agricultural areas.

Silicon-Mediated Regulation of Sodium Distribution in Barley Plants

Salinity is one of the largest problems in the world today. Silicon (Si)-mediated increase in plant tolerance to saline environment has been well documented, while the underlying mechanisms remain unclear. Monosilicic acid, polysilicic acid, and sodium (Na) were analyzed in the apoplast and symplast of roots, stems and leaves of salt-stressed barley plants in dynamics. Sodium moved predominantly via apoplastic pathway. The dynamics of Na in apoplast represented a parabolic curve. Soluble Si in nutrient solution increased the total Na in the roots but restricted the Na root-to-shoot transport via apoplastic pathway and reduced Na accumulation in stems and leaves. Plant exposure to high concentration of Na resulted in increased polysilicic acids in the root symplast and stem apoplast and symplast. These increases are attributable to Si redistribution within plant with its accumulation in stressed tissue. Probably, Si moves in the form of polysilicic acid. Under optimum or low stress growth conditions, Si mainly accumulated in the roots and leaves. Under higher stress, this Si can be redistributed to a mostly stress-affected place.

A brief overview of acute poisoning in sheep

Acute poisoning in sheep can occur following ingestion of toxic plants, including plants that they may eat normally such as ivy (Hedera spp.) and plants they avoid unless other forage is unavailable. Poisoning with plants containing grayanotoxins (Pieris and Rhododendron spp.) is very common in sheep, particularly when the weather is poor and they are hungry. Oak (Quercus spp.) poisoning is also relatively common in sheep, particular in years with a heavy acorn crop. Numerous plants contain cardiac glycosides and are a potential risk to sheep. Sudden death is frequently the first signs of plant toxicosis in livestock. Bites from adders (Vipera berus berus) may also occur in sheep but are likely to be underreported as the actual biting event is not witnessed. Envenomation may result in swelling and haematological, renal, hepatic and cardiac effects. Overdosage of drugs with a narrow therapeutic index may also be a risk. One such example is closantel which can result in blindness. Management of acute poisoning in sheep is supportive including removal from exposure, and providing analgesia, rehydration and potentially a rumenotomy for plant exposure in valuable animals.

On the Capability of the Epigeous Organs of Phragmites australis to Act as Metal Accumulators in Biomonitoring Studies

With a view of shedding light on the accumulation capability of the epigeous organs of common reed (Phragmites australis), employed worldwide in metal biomonitoring, an accumulation study of Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn was performed, focusing on leaves belonging to different whorls and culms. To this end, in five sampling sites on the littoral zone of the volcanic Lake Averno (Italy), and in one occasion (autumn) before plant senescence, leaves of different ages and culms were collected and analyzed for metal concentrations. In terms of the suitability for biomonitoring, culms demonstrated poor performances in relation to the low metal accumulation and the difficulties in sampling and processing, whereas leaves proved their effectiveness in highlighting whole plant exposure. Since the accumulation degree of Cr, Cu, Fe and Zn is unaffected by leaf age, the pooling of leaves from different whorls is advisable to improve the representativeness of samplings. This strategy becomes mandatory in the case of Ni, the non-monotonic age-dependent variations of which would affect the derivation of contamination gradients otherwise. For Mn, Cd and Pb, the accumulation patterns strictly dependent on age can instead be exploited in selecting the sensitivity of biomonitoring by focusing on the organs where they are preferentially accumulated: old leaves for Mn and young leaves for Cd and Pb.

Cultivation Technologies Applied in the Production of Tomato Plants for Obtaining Safe Food Products under the Conditions of Climate Change

This paper presents the results obtained from the research realized in controlled environmental conditions in a horizontal greenhouse where seedlings from varieties of tomato lines in the process of testing for approval in Romania were used. The research was carried out in a three-factorial experimental scheme, in which were taken into consideration as variation factors: three cultivars of tomatoes, 3 colors of light emitted by the LED bulbs and 3 intervals of time (15, 30 and 45 minutes/day) for plant exposure to the monochromatic additional light treatment. Biometric measurements were made on the height and diameter of the stems and assessments of seedling weight, as well as analyzes on nutrient composition, accumulated after three months of cultivation in the greenhouse. The results obtained are within the limits mentioned by the specialized literature for the best seedlings for the tested varieties of tomatoes.

Multiple Attack to Inflorescences of an Annual Plant Does Not Interfere with the Attraction of Parasitoids and Pollinators

Plants in the flowering stage need to ensure reproduction by protecting themselves from attack and by preserving interactions with mutualist pollinators. When different plant mutualists are using the same type of cues, such as volatile compounds, attraction of parasitoids and pollinators may trade off. To explore this, we compared volatile emission of Brassica nigra plants in response to single or dual attack on their inflorescences. Additionally, we recorded flower visitation by pollinators and the attraction of parasitoids in the greenhouse and/or field. Brassica nigra were exposed in the flowering stage to one or two of the following three attackers: Brevicoryne brassicae aphids, Pieris brassicae caterpillars, and Xanthomonas campestris pv. raphani bacteria. We found that single attack by caterpillars, and dual attack by caterpillars plus aphids, induced the strongest changes in plant volatile emission. The caterpillars’ parasitoid C. glomerata did not exhibit preference for plants exposed to caterpillars only vs. plants exposed to caterpillars plus aphids or plus bacteria. However, the composition of the pollinator community associated with flowers of B. nigra was affected by plant exposure to the attackers, but the total number of pollinators visiting the plants did not change upon attack. We conclude that, when B. nigra were exposed to single or dual attack on their inflorescences, the plants maintained interactions with natural enemies of the insect attackers and with pollinators. We discuss how chemical diversity may contribute to plant resilience upon attack.

Identifikasi Degradasi Tanah dan Pengaruh Faktor Penggunaan Lahan Terhadap Degradasi Tanah Pada Kebun Campuran Dan Semak Belukar Di Kecamatan Kairatu Kabupaten Seram Bagian Barat Propinsi Maluku

Soil degradation on scrub is higer than the mixed planting with indicators of soil degradation are pedestal, root plant exposure, rill and gully. Individually, the extent of land use, the density of upper vegetation and the density of lower vegetation have significant effect on the soil degradation at mixed plantation and scrub. Simultaneously, the extent of land use, the density of upper vegetation and the density of lower vegetation have significant effect on the soil degradation at mixed plantation and scrub. The factors that has the greatest effect on the soil degradation at mixed plantation are the extent of land use and density of lower vegetation, att the scrub, those factors are the density of upper and lower vegetation. Key words: Soil degradation, the extent of landuse, density of upper vegetation, density of lower vegetation, mixed plantation and scrub. ABSTRAK Besar degradasi tanah pada semak belukar lebih tinggi dibandingkan kebun campuran dengan indikator degradasi tanah adalah pedestal, akar terekspos, alur dan parit. Secara tunggal, luas penggunaan lahan, kerapatan vegetasi atas dan kerapatan vegetasi bawah berpengaruh nyata terhadap degradasi tanah pada penggunaan lahan kebun campuran dan semak belukar. Secara serempak, luas penggunaan lahan, kerapatan vegetasi atas dan kerapatan vegetasi bawah berpengaruh nyata terhadap degradasi tanah pada penggunaan lahan kebun campuran dan semak belukar. Faktor yang paling berpengaruh terhadap degradasi tanah pada kebun campuran adalah luas penggunaan lahan dan kerapatan vegetasi bawah, sedangkan pada semak belukar adalah kerapatan vegetasi atas dan kerapatan vegetasi bawah. Kata Kunci: degradasi tanah, luas penggunaan lahan, kerapatan vegetasi atas, kerapatan vegetasi bawah, kebun campuran dan semak belukar.