Phytotoxic effects of extract and essential oil of Eucalyptus saligna (Myrtaceae) leaf litter on grassland species

2017 ◽  
Vol 65 (2) ◽  
pp. 172 ◽  
Author(s):  
Eliane R. Silva ◽  
Diana C. Lazarotto ◽  
Joséli Schwambach ◽  
Gerhard E. Overbeck ◽  
Geraldo L. G. Soares

Under Eucalyptus plantations in the South Brazilian grassland region, few plants establish, and allelopathy may be involved in shaping this pattern. We aimed to assess the phytotoxicity of essential oil and aqueous extract of Eucalyptus saligna Sm. leaf litter on grassland species. We tested the effects of E. saligna pure oil and extract on germination, seedling growth, H2O2 levels and electrolyte leakage of seedling membranes of Paspalum notatum Flüggé, Eragrostis plana Ness (Poaceae), Trifolium repens L. and Lotus corniculatus L. (Fabaceae). Essential oil and aqueous extract of E. saligna affected all recipient species, even at the lowest amounts/concentrations, inhibiting germination and initial growth, and also increasing H2O2 levels and electrolyte leakage of seedling membranes. Essential oil consisted mainly of monoterpenes and presented α-pinene and 1,8-cineole as the major compounds. The extract contained phenolics, and lower levels of these compounds in the extract were associated with decreased phytotoxicity. We conclude that E. saligna contains phytotoxic compounds in leaf litter that generate oxidative stress and lead to membrane damage, affecting seeds and seedling growth. In addition, we relate E. saligna phytotoxicity to monoterpenes that may be released from leaf litter by volatilisation, and phenolics that may be leached by rainfall. Our study indicates that E. saligna has allelopathic potential on the tested grassland species.

Rodriguésia ◽  
2018 ◽  
Vol 69 (4) ◽  
pp. 2153-2161
Author(s):  
Letícia Rodrigues Vieira ◽  
Eliane Regina da Silva ◽  
Geraldo Luiz Gonçalves Soares ◽  
Claudimar Sidnei Fior ◽  
Eduardo Miranda Ethur ◽  
...  

Abstract Some exotic species threat the integrity of natural environments due to their invasive potential. They can affect other species by releasing secondary compounds in the soil. Morus nigra (Moraceae) is an invasive species of riparian forests in southern Brazil. The objective of this study was to verify if the aqueous extracts of fruit, fresh and dry leaves of M. nigra show phytotoxic effects on germination, seedling growth and membrane integrity of seedlings of Lactuca sativa. Extract concentrations of 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5 and 10% were tested. Germination rate and speed of germination were determined. Effects on initial growth were evaluated by measuring seedling root and shoot length, and membrane integrity was assessed by conductivity tests. Results showed the phytotoxicity of M. nigra aqueous extracts, causing significant inhibition on germination and seedling growth. The fruit extract was generally less phytotoxic than extracts from fresh and dry leaves. Moreover, the extracts induced changes in membrane integrity and caused morphological deformities in seedlings, such as necrotic roots and chlorotic plants. The high phytotoxicity of fruit, dry and fresh leaf extracts of M. nigra was evidenced, indicating the allelopathic potential of the species.


2020 ◽  
Vol 26 (2) ◽  
Author(s):  
Goverdhan Singh Thakur ◽  
Shriram Kunjam

Allelopathic effects of Parthenium hysterophorus were studied on seed germination and seedling growth of Triticum aestivum, Oryza sativa, Glycine max and Cajanus cajan. The shade dried leaves of Parthenium hysterophorus were soaked in distilled water for 24 hours at room temperature to obtain aqueous extract and sterilized seeds were treated with 2%, 4%, 6%, 8% and 10% concentration of P. hysterophorus leaves aqueous extract. The germinated seeds were counted every day to observe mean germination time. It has been found that significant time is taken to germinate with increasing concentration. It has been also observed that germination percentage, root length, shoot length and seedling vigour value were reduced at >2% as compared to control. The 10 % aqueous extract showed the maximum inhibitory effect on seedling growth. In the present investigation, the leaves aqueous extract of P. hysterophorus had strong inhibiting effects on seed germination and seedling growth. It is necessary to keep this weed under check at the emerging stage at agro crop field so that crop growth constraint may be avoided


2020 ◽  
Vol 9 (10) ◽  
pp. e5859108579
Author(s):  
Maicon Reginatto ◽  
Lisandro Tomas da Silva Bonome ◽  
Leonardo Khaôe Giovanetti ◽  
Henrique von Hertwig Bittencourt ◽  
Luciano Tormen ◽  
...  

Cover crops are used as a strategy to recover degraded soils, improving their physical, chemical and biological characteristics, as well as assisting in the control of weeds through allelochemical compounds released by the shoot degradation process. This work aimed to evaluate the phytotoxicity of the aqueous extract of the cover crops Raphanus sativus L., Avena strigosa (Schreb) and Vicia villosa R. on the germination and initial growth of Zea mays, Amaranthus spinosus L. and Ipomoea grandifolia (Dammer) O'Donnell, as well as to identify and quantify the phenolic compounds present in the extract. Straws from the dried and crushed cover crops were used. The extracts were obtained by mixing 10% R. sativus and A. strigosa, and 12% V. villosa in distilled water (m/v). DIC was used, with four replications, in a 3x4 factorial scheme, with 3 cover crops (R. sativus, A. strigosa and V. villosa) and 4 concentrations (0%, 25%, 50% and 75%). The variables analyzed were: germination, germination speed index (GSI), seedling growth, root protrusion (RP), root protrusion speed index (RPSI) and dry mass of the root and shoot. Higher concentrations of the extracts affected the initial development of maize and weeds. The phenolic compounds identified in greater quantity were benzoic acid, p-coumaric acid, followed by ferulic acid and p-hydroxybenzoic acid. It is suggested that studies of the same nature be carried out in the field, since the interactions between soil microorganisms, climatic conditions can interfere with the results.


2019 ◽  
Vol 37 ◽  
Author(s):  
V. ZUCARELI ◽  
E.M.P. COELHO ◽  
W.V. FERNANDES ◽  
E.M. PERES ◽  
J. STRACIERI

ABSTRACT: This study aimed to assess the allelopathic potential of the aqueous extract of the shoot of Sorghum bicolor at different phenological stages on seed germination and initial growth of kale (Brassica oleracea var. acephala) seedlings, which is considered a bioindicator species. The experiment was carried out at five development stages of S. bicolor (40, 50, 60, 70, and 80 days after emergence), which was used as aqueous extract at six concentrations (0, 20, 40, 60, 80, and 100%) applied in four replications per treatment in 10 or 50 kale seeds per plot. The percentage of germination, germination rate index, root growth, shoot length, and dry matter of kale seedlings were analyzed in the presence of this extract on different days of collection and concentrations. The aqueous extract of S. bicolor presented an allelopathic effect on germination and initial growth of kale seeds, with a higher inhibitory effect when more concentrated extracts from pre-flowering plants were used, which corresponds to 60 days after emergence. Thus, this stage should be recommended in the use of S. bicolor straw to help in controlling weeds.


2018 ◽  
Vol 11 (1) ◽  
pp. 55-67 ◽  
Author(s):  
Eliane R. da Silva ◽  
Luis H. R. da Silveira ◽  
Gerhard E. Overbeck ◽  
Geraldo L. G. Soares

2020 ◽  
Vol 7 (1) ◽  
pp. 86-97 ◽  
Author(s):  
Hadouda Benarab ◽  
Mohamed Fenni ◽  
Yacine Louadj ◽  
Habiba Boukhabti ◽  
Messaoud Ramdani

AbstractThe allelopathic potential of essential oil extracts from Artemisia herba-alba Asso. was assessed on seed germination of nine weeds and two wheat varieties. The samples were collected from El-Rasfa région (Sétif, Algeria). The essential oil was extracted using hydrodistillation of aerial part and characterized using gaz chromatography coupled with mass spectroscopy. The bioassays with organic solvent (ethanol) were tested using four different concentrations (0.2, 0.4, 0.6 and 0.8 µl/ml of oil/ethanol) on seed and seedling growth of the nine weeds and two wheat varieties. The yield obtained is 1.19%, and 36 compound had been identified. The main components are: camphor (28.58%), cis-thujone (22.03%), eucalyptol (11.65%) and trans-thujone (7.03%). The results of bioassays show that essential oil extracts has a significant effect on seed germination and seedling growth of the major weed tested and two wheat varieties. In conclusion, this study shows that the essential oil tested has an interesting allelopathic potential.


Author(s):  
Márcio Cavalli ◽  
Michele Da Silva Santos ◽  
Mara Karinne Lopes Veriato Barros ◽  
Helder Morais Mendes Barros ◽  
Karina Xavier Leite Barosi

<p class="Default"><span>A pecuária brasileira é sustentada em pastagens, pela sua praticidade e economia. Entre as espécies anuais de inverno mais utilizadas para pastejo na Região Sul do Brasil estão à aveia preta e o </span><span>a</span><span>zevém, isolados ou em misturas, em função da facilidade na aquisição de sementes e em relação ao ciclo de produção das espécies. Entre as espécies de verão o Capim-Sudão vem se destacando, usado como alternativa para diminuir as dificuldades encontradas em obter forragem na época seca do ano, por facilidade de cultivo, rusticidade, tolerância à seca, rapidez no estabelecimento e crescimento, e facilidade de manejo sob corte e ou pelo pastejo direto. O presente estudo objetivou-se verificar o potencial alelopático do extrato aquoso em diferentes concentrações da aveia preta e azevém sobre a germinação e crescimento inicial do capim-Sudão. O experimento foi realizado na safra 2013/14, na Universidade do Oeste de Santa Catarina (UNOESC), campus de São José do Cedro, Santa Catarina, em estufa. Para o delineamento estatístico foi utilizado o método DBC (delineamento em blocos casualizados) fatorial, com três tratamentos e cinco doses com quatro repetições. Pela porcentagem de germinação, comprimento de plantas e comprimento de raízes comparadas nas dosagens do extrato aquoso houve efeito alelopático na germinação do Capim-Sudão. E pelos índices de massa fresca e seca da parte aérea e radicular, e também visto no índice de velocidade de germinação que a partir das doses de 50% da solução aquosa dos extratos da </span><span>aveia e a</span><span>zevém e da mistura </span><span>a</span><span>veia + </span><span>a</span><span>zevém que ocorreu efeito alelopático sobre a germinação do Capim-Sudão.</span></p><p align="center"><strong><em>Allelopathic potential of the aqueous extract of black oats and ryegrass in the germination and initial growth of the sudan grass</em></strong></p><p><strong>Abstract</strong><strong>: </strong>The Brazilian livestock farming is sustained in pastures, due to its practicality and economy. Among the annual winter species most used for grazing in southern Brazil are black oats and ryegrass, isolated or in mixtures, due to the ease of seed acquisition and the production cycle of the species. Among the summer species, Sudan grass has been used as an alternative to reduce the difficulties encountered in obtaining fodder in the dry season of the year, for ease of cultivation, rusticity, drought tolerance, fast establishment and growth, and ease of cultivation. Handling under cut and / or by direct grazing. The objective of the present study was to verify the allelopathic potential of the aqueous extract in different concentrations of black oats and ryegrass on the germination and initial growth of the Sudan grass. The experiment was carried out in the 2013/14 harvest, at the University of the West of Santa Catarina (UNOESC), in the São José do Cedro campus, in the greenhouse. For the statistical design, the DBC (randomized complete block design) method was used, with three treatments and five doses with four replicates. By the percentage of germination, plant length and root length compared in the dosages of the aqueous extract, there was an allelopathic effect on the germination of the Sudan Grass. And by the fresh and dry mass index of the shoot and root, and also seen in the rate of germination that from the doses of 50% of the aqueous solution of the extracts of oats and ryegrass and the oat + ryegrass mixture that occurred allelopathic effect On the germination of Sudan Grass.</p><p class="Default"><span><br /></span></p>


Author(s):  
Eliane R. Silva ◽  
José M. Igartuburu ◽  
Gerhard E. Overbeck ◽  
Geraldo L. G. Soares ◽  
Francisco A. Macías

2020 ◽  
Vol 8 (2) ◽  
pp. 643
Author(s):  
Gabriela Hoffmann ◽  
Mayra Luiza Schelter ◽  
Diogo Luiz Fruet ◽  
José Cristimiano Dos Santos Neto ◽  
Cleber Daniel De Goes Maciel ◽  
...  

Weedy rice belongs to the same species as grown rice, and because it has similar morphophysiological characteristics, its control is difficult, bringing negative effects to the crop. Thus, the work aimed to evaluate the allelopathic potential of the main paddy rice cultivars sowing in Santa Catarina on weedy rice. In the laboratory, with treatments organized in a 4 x 5 factorial scheme, the aqueous extract of four paddy rice cultivars (SCSBRS Tio Taka, SCS 116 Satoru, SCS 121 CL and SCS 122 Miura) was evaluated in five concentrations (0, 25, 50, 75 and 100%). In a greenhouse, with treatments in a 4 x 2 factorial scheme, the straw allelopathy capacity of the same rice cultivars in two quantities (0.0 and 3.0 t ha-1) was evaluated to suppress germination and weedy rice initial growth. All experiments were carried out in a completely randomized design. In the first assay, the aqueous extract of the paddy rice cultivars used in the state of Santa Catarina did not have an allelopathic effect on weedy rice. In the second assay, it was found that the presence of rice straw reduced the density of weedy rice plants. However, the presence of straw on the soil favored the initial growth of the weed, significantly increasing the plant height, number of leaves per plant and shoot dry biomass.


2021 ◽  
Vol 27 (2) ◽  
pp. 201-212
Author(s):  
Bilal Ahmad Khan

ABSTRACT Chemical weed control method caused environmental hazards and residual effects in crops and soil. Alternate approach to control weeds is getting attentions in sustainable production system. Use of aqueous extracts of weed is getting scientific attention as eco-friendly alternative to chemical herbicides especially under scenario of fast increasing herbicide resistance in weeds. To investigate the herbicidal potential of aqueous extract of winter weed of Sonchus oleraceus L. (Sow thistle) on summer weed Oryza punctate L. (red rice) seed emergence and initial seedling growth, a study was planned. In this study, seeds of O. punctate were incubated in seven concentrations (0, 0.25, 0.50, 1, 2, 4, and 8%) of different parts i.e. leaves, stem, flower of S. oleraceus. All the tested concentrations of various plant parts of S. oleraceus significantly inhibited the mean emergence time, emergence index, emergence percentage (%), time taken to 50% emergence as well as growth of O. punctata weed. However, maximum mean emergence time (5.26 days), minimum germination index (1.69), germination percentage (40%), root length (2.04 cm), shoot length (5.71 cm), fresh weight (59 g), dry weight (4.06 g) was noted at 8% concentration with fruit aqueous extract of S. oleraceus. Seed of O. punctata take maximum time to complete 50% emergence (3.33 days) under control where we applied distilled water. Results suggested fruit extract of S. oleraceus at 8% concentration can be used potential bio-herbicide for the control of O. punctate. Key words: Chemical, eco-friendly, herbicidal potential, fruit extract


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