Response of vetch, lentil, chickpea and red pea to pre- or post-emergence applied herbicides

Broad-leaved weeds constitute a serious problem in the production of winter legumes, but few selective herbicides controlling these weeds have been registered in Europe. Four field experiments were conducted in 2009/10 and repeated in 2010/11 in Greece to study the response of common vetch (Vicia sativa L.), lentil (Lens culinaris Medik.), chickpea (Cicer arietinum L.) and red pea (Lathyrus cicera L.) to several rates of the herbicides pendimethalin, S-metolachlor, S-metolachlor plus terbuthylazine and flumioxazin applied pre-emergence, as well as imazamox applied post-emergence. Phytotoxicity, crop height, total weight and seed yield were evaluated during the experiments. The results of this study suggest that common vetch, lentil, chickpea and red pea differed in their responses to the herbicides tested. Pendimethalin at 1.30 kg ha-1, S-metolachlor at 0.96 kg ha-1 and flumioxazine at 0.11 kg ha-1 used as pre-emergence applied herbicides provided the least phytotoxicity to legumes. Pendimethalin at 1.98 kg ha-1 and both rates of S-metolachlor plus terbuthylazine provided the greatest common lambsquarters (Chenopodium album L.) control. Imazamox at 0.03 to 0.04 kg ha-1 could also be used as early post-emergence applied herbicide in common vetch and red pea without any significant detrimental effect

Effectiveness of olive fruit polyphenol extract combined with aqueous extracts of solid wastes of pomegranate or/ and orange juice against important plant pathogens - Part 2 (in vivo studies)

Olive fruit extracts, combined with pomegranate and orange waste extracts, isolated using microwave assisted extraction technique, were used as a potential alternative crop protection method against Verticillium dahliae, Rhizoctonia solani, Botrytis cinerea and Pyrenochaeta lycopersici on tomato plants. For the evaluation of the antimicrobial activity, various mixtures of the extracts were applied on 15 days old tomato plants, variety “Bella Dona”, infected by the above-mentioned pathogens. After 40 days of treatments, plant growth parameters such as plant fresh and dry weight, root weight, plant height, number of blossoms and number of formed fruits were calculated in order to assess the extract effectiveness. The results indicated that the four pathogens dramatically reduced tomato growth. In contrast, most of the evaluated extracts provided satisfactory control of the pathogens resulting in tomato growth similar to that of the uninfected control plants. Conclusively, the use of these polyphenolic extracts could protect tomato plants in case of fungal infection. Copyright © 2021 by authors, all rights reserved. Authors agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International Licens

Carbon assimilation, isotope discrimination, proline and lipid peroxidation contribution to barley (Hordeum vulgare) salinity tolerance

Barley (Hordeum vulgare L.) exhibits great adaptability to salt tolerance in marginal environments because of its great genetic diversity. Differences in main biochemical, physiological, and molecular processes, which could explain the different tolerance to soil salinity of 16 barley varieties, were examined during a two-year field experiment. The study was conducted in a saline soil with an electrical conductivity ranging from 7.3 to 11.5 dS/m. During the experiment, a number of different physiological and biochemical characteristics were evaluated when barley was at the two-to three-nodes growing stage (BBCH code 32–33). The results indicated that there were significant (p < 0.001) effects due to varieties for tolerance to salinity. Carbon isotopes discrimination was higher by 11.8% to 16.0% in salt tolerant varieties than that in the sensitive ones. Additionally, in the tolerant varieties, assimilation rates of CO2 and proline concentration were 200% and up to 67% higher than the sensitive varieties, respectively. However, in sensitive varieties, hydrogen peroxide and lipid peroxidation were enhanced, indicating an increased lipid peroxidation. The expression of the genes Hsdr4, HvA1, and HvTX1 did not differ among barley varieties tested. This study suggests that the increased carbon isotopes discrimination, increased proline concentration (play an osmolyte source role), and decreased lipid peroxidation are traits that are associated with barley tolerance to soil salinity. Moreover, our findings that proline improves salt tolerance by up-regulating stress-protective enzymes and reducing oxidation of lipid membranes will encourage our hypothesis that there are specific mechanisms that can be co-related with the salt sensitivity or the tolerance of barley. Therefore, further research is needed to ensure the tolerance mechanisms that exclude NaCl in salt tolerant barley varieties and diminish accumulation of lipid peroxides through adaptive plant responses. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Potential synergistic action of liquid olive fruit polyphenol extract with aqueous extracts of solid wastes of pomegranate or/and orange juice industry as organic phyto-protective agents against important plant pathogens - Part 1 (in vitro studies)

In this research study potential synergistic action of aqueous extracts of olive-pomegranate-orange fruits isolated by microwave assisted extraction were investigated as biocontrol agents against several plant pathogenic fungi. The aim of the research study was the production of mixed liquid extracts to be used as natural phytoprotective agents in organic farming. The results proved that the use of 100%-pure olive fruit polyphenol extract affected the mycelium growth of B. cinerea, V. dahliae, R. solani, E. lata, M. laxa, P. lycopersici and P. punicae. However, it did not affect the mycelium growth of F. oxysporum f. sp., lycopersici, A. niger, and G. graminis. Moreover, pomegranate polyphenol extract at 100% concentration inhibited mycelium growth of B. cinerea. Various olive-pomegranate-orange polyphenol aqueous extract combinations may be used in order to control the mycelium growth of the majority of the tested microorganisms. However, the use of any combination and concentrations of the tested samples (1-72) did not affect the mycelium growth of F. oxysporum f. sp., lycopersici, A. niger, and G. graminis thus, their use as biological control agent is not recommended. According to the findings of the present research, it can be suggested that the olive fruit polyphenol extract be used as potential biocontrol agent, in order to stimulate mycelium growth of various plant pathogenic fungi. Copyright © 2020 by authors, all rights reserved. Authors agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International Licens

Impact of Soil Salinity on Barley Allelopathic Potential and Main Secondary Metabolites Gramine and Hordenine

Crop allelopathy is a useful tool in integrated weed suppression. Although the abiotic stresses affect the produced secondary metabolites, the impact of soil salinity on crop allelopathic potential under field conditions has not been investigated. So, the effect of soil salinity on the allelopathic activity of 18 allelopathic barley (Hordeum vulgare L.) varieties was investigated. The allelopathy of barley grown on saline and non-saline soils was investigated during a 2-year field experiment using the Perlite-based bioassay with rigid ryegrass (Lolium rigidum L.) as plant indicator. The two main allelopathic substances in barley, gramine and hordenine, were determined using the high-performance liquid chromatography with tandem mass spectrometry. The results indicated that rigid ryegrass germination and root length were adversely affected by the barley aqueous extracts. The secondary metabolite gramine was detected in greater concentrations than those of hordenine. For most barley varieties, soil salinity reduced the phytotoxicity of aqueous extracts, as well as the concentration of gramine. However, gramine and hordenine were not highly correlated with the barley extract phytotoxicity, indicating the possible involvement of other allelopathic substances. In conclusion, the barley allelopathic potential probably decreases in soils with high salinity. © 2020, Springer Science+Business Media, LLC, part of Springer Nature