Seasonal variations in UV-B absorbing capacity and allelopathic potential of Dittrichia viscosa leaf rinsates

1997 ◽  
Vol 75 (8) ◽  
pp. 1371-1374 ◽  
Author(s):  
M. Stephanou ◽  
Y. Manetas

The seasonal variations in the amount and the allelopathic potential of the water-soluble, leaf epicuticular exudates in the Mediterranean ruderal Dittrichia viscosa were investigated. Both parameters peaked during the dry, hot, and sunny summer, confirming the prediction that the seasonal fluctuations should be commensurate with the ascribed antitranspirant and phytotoxic functions. In particular, the drainage of the material to the soil with the heavy autumn rains provides excellent timing for exerting its strong allelopathic interference on seed germination, affording D. viscosa a considerable competitive advantage. Key words: allelopathy, Dittrichia viscosa, leaf rinsates, seasonal variations.

1992 ◽  
Vol 22 (9) ◽  
pp. 1310-1319 ◽  
Author(s):  
Olle Zackrisson ◽  
Marie-Charlotte Nilsson

Indoor and outdoor experiments demonstrated that allelopathy is an important factor explaining seed regeneration failures of Scots pine (Pinussilvestris L.) in forest floor vegetation dominated by the dwarf shrub Empetrumhermaphroditum Hagerup. Scanning electron micrograph views of the leaf surfaces of E. hermaphroditum reveal secretory glands that are shown to be involved in the release of water-soluble phytotoxic substances. Bioassays indicate that low doses and short exposure times of seeds to leachates have strong negative effects on germination and early root development. Activated carbon can eliminate the inhibitory effects of leachates and litter. This technique demonstrates the occurrence of allelopathic interference by E. hermaphroditum on seed germination of both Scots pine and aspen (Populustremula L.). In a field experiment the allelopathic effects by E. hermaphroditum are strong during early spring when germination and growth initiate and ground ice still is present. Extracts passed through soils collected from an E. hermaphroditum site were detoxified, while those passed through sterilized soil were not. Therefore, microorganisms may detoxify the allelochemicals under some environmental conditions.


2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Neha Chopra ◽  
Geeta Tewari ◽  
Lalit M. Tewari ◽  
Brij Upreti ◽  
Naveen Pandey

The present study was undertaken to assess the allelopathic effect of Echinochloa colona L. and Cyperus iria L. in relation to the germination and primary growth of Oryza sativa L. (rice) and Glycine max L. (soyabean). Effects of dichloromethane (DCM) and double distilled water soluble (DDW) fractions of E. colona L. and C. iria L. root and aerial part extracts reduced germination and suppressed early seedling growth of rice and soyabean. With increase in extract concentration from 1 to 100 mg/mL, a gradual decrease in seed germination and seedling length occurred. The highest growth of G. max seedling was recorded in DDW fraction of E. colona aerial part extract at 1 mg/mL concentration with 94% germination and the lowest length was found in DCM fraction of C. iria root extract at 100 mg/mL concentration with 65% germination. In O. sativa, the highest length was noted at 1 mg/mL concentration in DDW fraction of E. colona aerial part extract with 82% germination and the lowest length was found in DCM fraction of C. iria and E. colona root extracts with germination 57% and 62%, respectively, at 100 mg/mL concentration. The results suggested that these weeds had good allelopathic potential which reduces germination and plant growth.


1970 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Bista ◽  
G. B. Khattri ◽  
B. D. Acharya ◽  
S. C. Srivastava

To find out the ability of Orobanche seeds to germinate immediately after seed set, seeds were germinated periodically at an interval of three months for one year in GR24. Some Orobanche seeds were capable of germination immediately after seed set but most required about nine months as after ripening or incubation period to be able to germinate. The phenomenon of after ripening in Orobanche seeds could be taken as an ecological measure to dormant over following unfavorable wet summer season. The growth hormone studies on Orobanche seed germination have shown that GA3 at a concentration of 100 ppm substantially enhanced seed germination when applied during pre-conditioning period. NAA showed some stimulatory effect at 0.5 - 1.0 ppm when applied during post-conditioning period but the hormone if applied during pre-conditioning period inhibited the germination. Kinetin failed to stimulate the germination at all the concentrations tested. Key words: Germination, root-parasite, hormone. Ecoprint Vol.11(1) 2004.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yankun Sun ◽  
Jiaqi Xu ◽  
Xiangyang Miao ◽  
Xuesong Lin ◽  
Wanzhen Liu ◽  
...  

AbstractAs the global population continues to increase, global food production needs to double by 2050 to meet the demand. Given the current status of the not expansion of cultivated land area, agronomic seedlings are complete, well-formed and strong, which is the basis of high crop yields. The aim of this experiment was to study the effects of seed germination and seedling growth in response to silicon (from water-soluble Si fertilizer). The effects of Si on the maize germination, seedling growth, chlorophyll contents, osmoprotectant contents, antioxidant enzyme activities, non-enzymatic antioxidant contents and stomatal characteristics were studied by soaking Xianyu 335 in solutions of different concentrations of Si (0, 5, 10, 15, 20, and 25 g·L−1). In this study, Si treatments significantly increased the seed germination and per-plant dry weight of seedlings (P < 0.05), and the optimal concentration was 15 g·L−1. As a result of the Si treatment of the seeds, the chlorophyll content, osmotic material accumulation and antioxidant defence system activity increased, reducing membrane system damage, reactive oxygen species contents, and stomatal aperture. The results suggested that 15 g·L−1 Si significantly stimulated seed germination and promoted the growth of maize seedlings, laying a solid foundation for subsequent maize growth.


Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1076
Author(s):  
Döme Barna ◽  
Szilvia Kisvarga ◽  
Szilvia Kovács ◽  
Gábor Csatári ◽  
Ibolya O. Tóth ◽  
...  

Organic and ecological farming programs require new and efficient biostimulants with beneficial properties for the sustainable and safe production of seedlings and ornamental plants. We examined the effect of non-fermented and lacto-fermented alfalfa brown juice (BJ) on seed germination and the vegetative, physiological, and anatomical properties of French marigold (Tagetes patula L. ‘Csemő’) plants which were treated with 0.5–10% fermented and non-fermented BJ, with tap water applied as a control. Applying 0.5% fermented BJ significantly improved seed germination compared with non-fermented BJ, resulting in an increase of 9.6, 11.2, 10.9, and 41.7% in the final germination percent, germination rate index, germination index, and vigor index, respectively. In addition, it increased the root and shoot length by 7.9 and 16.1%, respectively, root and shoot dry mass by 20 and 47.6%, respectively, and the number of leaves by 28.8% compared to the control. Furthermore, an increase in contents of water-soluble phenol, chlorophyll a and b, and carotenoid was reported upon the application of 0.5% fermented BJ, while peroxidase activity decreased. Our results prove that alfalfa BJ can be enrolled as a biostimulant as part of the circular farming approach which supports the sustainable horticultural practice.


1986 ◽  
Vol 66 (2) ◽  
pp. 377-381 ◽  
Author(s):  
P. A. SCHUPPLI

Soils were extracted by hot water, dilute CaCl2, and by mannitol-CaCl2 solutions and boron was determined by either azomethine-H or the curcumin method. Results were strongly method dependent; in particular results by the simplest method, mannitol-CaCl2, were generally lower and not highly correlated (r = 0.64) with those by the recommended procedure. This procedure involves extraction with hot distilled H2O (2:1 solution:soil), centrifugation, filtration, color development with azomethine-H and correction for background color. Extractable boron values by this procedure ranged from 0.1 to 1.4 mg kg−1. Background color can be further reduced by the substitution of 0.02 M CaCl2 for distilled water. Key words: CSSC reference soil samples, hot-water-soluble boron


1997 ◽  
Vol 75 (11) ◽  
pp. 1903-1912 ◽  
Author(s):  
Kyeong W. Yun ◽  
M. A. Maun

Greenhouse studies were conducted to test allelopathic effects of Artemisia campestris ssp. caudata on seed germination and seedling growth of several sand-dune species and colonization by mycorrhizal fungi. The aqueous extracts of A. campestris showed no inhibitory effect on seed germination, seedling elongation, or dry-weight growth of plants at lower concentrations (10 and 50%), but 100% concentration of the extracts caused varying degrees of inhibition depending on the test species. The mixing of dry leaves of seedlings of A. campestris to the sand showed severe inhibition of Elymus canadensis seedlings. The percent germination of test species in soil from the rhizosphere of A. campestris was significantly lower than that of the control. The leaf area and dry weight were also lower but the differences were not significant. The aqueous extract inhibited mycorrhizal fungal colonization in roots of three sand-dune grasses. Key words: allelopathy, Artemisia campestris ssp. caudata, seed germination, seedling growth, mycorrhizal fungi.


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:


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