Effects of plant extracts of Bothriochloa pertusa and Urochloa mosambicensis on seed germination and seedling growth of Stylosanthes hamata cv. Verano and Stylosanthes scabra cv. Seca

1997 ◽  
Vol 48 (8) ◽  
pp. 1257 ◽  
Author(s):  
F. D. Hu ◽  
R. J. Jones

Effects of osmotic stress and of aqueous plant extracts from 4 pasture species on seed germination and seedling growth of the tropical legumes S. hamata (L.) Taub cv. Verano and S. scabra Vog. cv. Seca were investigated. Allelopathic effects of plant extracts from B. pertusa (L.) A. Camus were measured on S. scabra cv. Seca in terms of lower germination (35%) and shorter root length (35%). Extracts from Urochloa mosambicensis(Hack.) Dandy cv. Nixon had no adverse effect on Seca germination, but also reduced Seca root length. There was no evidence to support the hypothesis that B. pertusa had allelopathic effects on Verano germination or seedling growth. Extracts from Verano and Seca also reduced germination, seedling weight, and root length of Seca as well as root length of Verano. Root length was more sensitive than seedling length for ascertaining allelopathic effects, as there was no osmotic potential effect on root length up to 300 mmol/kg, whereas seedling weight and shoot length declined linearly with increasing osmotic potential (r = -0·92 and -0·99, respectively). Germination responses of Verano and Seca in solutions of both mannitol and polyethylene glycol-600 (PEG) were similar up to 300 mmol/kg, but at 600 mmol/kg Verano had a significantly higher germination in mannitol. Since the osmotic potential of the plant extracts did not exceed 78 mmol/kg, the use of osmotically adjusted control treatments had little effect on the conclusions drawn from using a distilled water control treatment.

Author(s):  
Weihong Sun ◽  
Guofeng Yang ◽  
Lili Cong ◽  
Juan Sun ◽  
Lichao Ma

Background: Plant allelopathy refers to the release of chemicals from plants or microorganisms into the environment, may have direct or indirect, beneficial or harmful effects on other plants or microorganisms. When plants grow in an unfavorable environment,more allelochemicals will be secreted and the expression of allelopathic effects will increase, giving plants a certain competitive advantage. Hairy vetch is one of the most promising allelopathic crops and the aqueous extract of hairy vetch has an inhibitory effect on the root length and seedling height of grass crops. The current study aimed to study the allelopathic effect of hairy vetch on alfalfa, and exploring an ecological method to remove the root system of alfalfa.Methods: In this experiment, the allelopathic effects of the seeds, stems and leaves, roots extracts and root exudates (0, 3, 6, 9 and 12 mg·mL-1) on the seed germination and seedling growth of alfalfa were evaluated. And the main allelopathic substances from the stem and leaf extract were isolated and identified using high performance liquid chromatography- mass spectrometry (HPLC-MS).Result: The results showed that all of the extracts can inhibit alfalfa seed germination and seedling growth and stem and leaf extract had the strongest inhibitory effect, especially for inhibiting the root growth. A main allelochemical substance, o-coumaric acid, was screened out and the root length of alfalfa was completely inhibited at 1.6 mg·mL-1 of o-coumaric acid. The findings of these experiments show hairy vetch has strong allelopathic effect on alfalfa and o-coumaric acid is a chemical growth inhibitor.


Nativa ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 261
Author(s):  
João Alves Ferreira Pereira ◽  
Tatiana Maria da Silva ◽  
Andreza Raquel Barbosa de Farias ◽  
Alexandre Bosco de Oliveira

POTENCIAL ALELOPÁTICO DE EXTRATOS DE Cyperus rotundus L. NA GERMINAÇÃO E ESTABELECIMENTO DE PLÂNTULAS DE FEIJÃO-CAUPI Este trabalho investigou os efeitos alelopáticos de extratos de Cyperus rotundus L. na germinação de sementes e crescimento inicial das plântulas de Vigna unguiculata L. Walp. Extratos alcoólicos nas concentrações 0; 1,5%; 3,0%; 4,5%; 6,0%; 7,5% e 9,0%, obtidos a partir da trituração de folhas de C. rotundus L. foram utilizados para umedecimento das folhas de papel toalha “germitest”. Os dados foram submetidos a análise de variância pelo F e as médias comparadas pelos testes de Tukey e Kruscal-Wallis, ambos a 5% de probabilidade. A primeira contagem de germinação, índice de velocidade de germinação, comprimento de raiz, comprimento da parte aérea e massa seca da raiz do feijão-caupi foram analisados de forma paramétrica, sendo constatado que apenas houve significância na variável primeira contagem e uma redução na germinação em relação ao tratamento controle em torno de 10%. Nas condições em que essa pesquisa foi realizada, os extratos alcoólicos de C. rotundus L. não afetam a germinação de sementes e crescimento inicial das plântulas de feijão-caupi.Palavras-chave: tiririca, alelopatia, interferência, plantas daninhas. ABSTRACT:This study aimed to investigate the allelopathic effects of Cyperus rotundus L. extracts on seed germination and early development of seedlings of Vigna unguiculata L. Walp. Alcoholic extracts at concentrations of 0, 1.5%, 3%, 4.5%, 6.0%, 7.5%, and 9.0% were obtained by crushing C. rotundus L. leaves used to moisten the “germitest” paper sheets. The data were subjected to analysis of variance and also both Tukey and Kruscal-Wallis tests were carried out at 5% for the data means. The first germination count, germination speed index, root length, shoot length, and dry root weight of cowpea were parametrically analyzed. The only variable with significance was first germination count. The germination reducted in relation to the control treatment around 10%. Thus, in the conditions used in this research, alcoholic extracts of C. rotundus L. did not affect either seed germination or early growth of cowpea seedlings.Keywords: nut grass, allelopathy, interference, weeds. DOI:


Genetika ◽  
2012 ◽  
Vol 44 (2) ◽  
pp. 235-250 ◽  
Author(s):  
Ahmad Dadashpour

The effects of different salt sources (C Cl2, NaCl, and KCl) and concentrations, as measured by electrical conductivity, (0, "control", 1, 3, 5, 7 and 9 dS m-1) on seed germination and seedling growth of ?Ferro?, ?Obez?, ?RS 841? and ?Strong Tosa F1? pumpkin varieties used as rootstock were investigated in this study. The results showed that germination rate, root length, shoot length, fresh root weight, dry root weight, fresh shoot weight and dry shoot weights tend to decrease when the electrical conductivity of the solution is higher than 5 dS m-1, independent of salt sources and in all of the varieties. Three days after seeding, a germination ratio of 5 % was obtained from RS 841 variety in all salt source and concentrations, while a germination ratio over 50 % was obtained in ?Strong Tosa? variety for the same conditions except CaCl2 salt source. Nevertheless, seeds germinated in medium having high concentrations of CaCl2 had lower germination rate and poor seedling growth, compared to media having the same concentrations of NaCl and KCl. It was concluded that all of the varieties studied were more sensitive to the concentrations prepared using CaCl2 than that of the KCl, and NaCl.


Weed Science ◽  
1984 ◽  
Vol 32 (6) ◽  
pp. 757-761 ◽  
Author(s):  
Nagi Reddy Achhireddy ◽  
Megh Singh

Allelopathic effects of lantana (Lantana camaraL. ♯3LANCA) residues (root, shoot), foliar leachates, and the soil (where lantana was grown) on milkweedvine (Morrenia odorataLindl. ♯3MONOD) seed germination and growth over a 30-day period were examined. Foliar leachates or the soil collected from the field where lantana had been growing had no effect on the final germination percentage or the seedling growth of milkweedvine. Incorporation of dried lantana shoot or root material into soil had no effect on the final percentage germination but caused significant reductions in milkweedvine growth over a 30-day test period. Roots were more inhibitory than shoots. Fifty percent of milkweedvine seedlings died within 15 days after germination at 1% (w/w) dried lantana root incorporation into the soil, and higher concentrations increased seedling death. Lantana roots incorporated into the soil produced foliar symptoms such as wilting and desiccation, whereas lantana shoots incorporated into the soil produced yellowing of the foliage of milkweedvine. Allelopathic activity of lantana residues was still strong even after decomposition of lantana residues for 4 weeks prior to the planting of milkweedvine seeds.


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