Effects of Thiourea and Allylthiourea on the Germination of the Seed of Striga lutea

Brown, Rex V.; Edwards, Maurice E.

doi:10.1038/155455a0

Cited by 26 publications

(8 citation statements)

References 6 publications

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“…D'autres sorgolCones trop instables pour pouvoir &tre identifiCes dans le cadre de ces experiences, ou des composCs de nature totalement diffkrente, pourraient donc jouer un r61e plus important dans la stimulation de la germination (Netzly et al 1988;Hess et al 1992). En fait, des composCs aussi variCs que la thiourCe et I'allylthiourCe (Brown et Edwards 1945), la kinetine (Worsham et al 1959;Yoshikawa et al 1978;Hsiao et al 1981c) et le thidiazuron (Babiker et al , 1992, des dCrivCs de la coumarine (Worsham et Klingman 1962), 1'Cthylkne (Egley et Dale 1970) (voir B ce propos la synthkse d ), l'acide sulfurique (Egley 1972) et l'hypochlorite de sodium (Hsiao et al 1981c) peuvent stimuler la germination de la graine de Striga.…”

Section: Le Stimulant De Germinationunclassified

La relation entre le Striga hermonthica et ses hôtes: une synthèse

Olivier¹

1996

Can. J. Bot.

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R&sumC : La mauvaise herbe parasite Striga hermonthica inflige des pertes de rendement considCrables au mais, au mil et au sorgho en Afrique. L'importance des dommages subis par les cultures est liCe B leur interaction Ctroite avec le parasite. La graine de S. hermonthica germe en rCponse B des stimulants de germination exsudCs par les racines de cCrCales. L'extrCmitC de la radicule se differencie ensuite en un haustorium qui s'attache B une racine de l'hate et pCnbtre ses tissus. Une connexion est alors Ctablie entre les systbmes vasculaires des deux plantes, ce qui permet au parasite de s'approvisionner en eau, en ClCments minCraux et en composCs organiques nkcessaires B son dCveloppement. Le S. hermonthica affecte Cgalement le mCtabolisme et la photosynthkse de son hate. Aucune mCthode de lutte efficace n'est actuellement accessible au paysan africain. L'application de stimulants de germination et d'herbicides, la pratique de rotations et d'associations culturales, la lutte biologique et la sClection de cultivars n'ont donnC jusqu'i maintenant que des rCsultats imparfaits. Une meilleure comprChension des mCcanismes de rCsistance de l'hbte est nCcessaire pour dCvelopper de nouvelles mCthodes de lutte contre le parasite. Abstract:The parasitic weed Striga hermonthica causes considerable yield losses in maize, pearl millet, and sorghum in Africa. The extent of the damage caused to crops is related to their close interaction with the parasite. The S. hermonthica seed germinates in response to germination stimulants exuded by cereal roots. The rootlet extremity then turns into a haustorium that attaches itself to the host root and penetrates its tissue. In this manner, a connection is established between the vascular systems of both plants, allowing absorption of water, minerals, and organic compounds that are essential for the parasite's development. S. hermonthica also affects the host's metabolism and photosynthesis. No effective control method against the parasite is available for the African peasants. The utilization of germination stimulants and herbicides, the rotation practice, and intercropping as well as biological control and varietal selection have given disappointing results so far. A better understanding of host resistance mechanisms is necessary to develop new methods for the control of the parasite.

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Section: Le Stimulant De Germinationunclassified

La relation entre le Striga hermonthica et ses hôtes: une synthèse

Olivier¹

1996

Can. J. Bot.

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“…In a replicated experiment where groundnuts, sugar bean (Phaseolus vulgaris L.), sunn hemp and buckwheat were sown previous to a maize crop (which is also attacked by this parasite), these workers showed that 'there was good reason for suspecting that groundnuts, sugar beans, and sunn hemp had actually destroyed much of the St*a seed by causing it to germinate' and later die owing to the presumed lack of a host plant. Brown & Edwards (1945) have shown that under certain conditions thiourea and allylthiourea will bring about germination of a small percentage of Striga Qsiatica seed in the absence of the host stimulant. Andrews (1945) showed that the excretions from the roots of leguminous and other non-gramineous plants will induce germination of the seed of S. hmonthica Benth.…”

Section: Introductionmentioning

confidence: 98%

THE PARASITISM OF STRIGA HERMONTHICA BENTH. ON LEGUMINOUS PLANTS

Andrews¹

1947

Annals of Applied Biology

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Pot experiments at the Gezira Research Farm showed that Striga hmonthica Benth. is not contined to the Gramineae but can also parasitize groundnuts, cowpea, dolichos bean and soya bean, causing a loss in yield in all but the last-named. The Strigu plants developing on the roots of these hosts were small, apparently ill-nourished and did not grow more than I cm. above the ground, in contrast to the vigorous, flowering Strigu plants that develop on sorghum. The greatest reduction in yield in these experiments was in dolichos bean, where the aerial growth was reduced 60 % ; no significant reduction in root weight was found in groundnuts, cowpea or soya bean. The last-named plant appeared to be feebly parasitized by S. hermonthica. A reduction in total nodule weight, but not in number of nodules, was obtained in groundnuts and cowpea. Parasitized dolichos bean showed a reduction in both the number of nodules and in nodule dry weight; in groundnuts, the later fruit production was seriously reduced.The use of these leguminous crops to clean Strigu-infested soil is discussed.

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“…Vatke is important on legumes ( Reid & Parker, 1979). Most Striga species produce large numbers of seeds with prolonged viability and special germination requirements (Andrews, 1945;Brown & Edwards, 1945;Brown, 1965;Egley, 1972). In order to germinate, seeds must be conditioned in a warm moist environment for several days and then exposed to an exogenous germination stimulant (Brown & Edwards, 1945).…”

Section: Introductionmentioning

confidence: 99%

“…Most Striga species produce large numbers of seeds with prolonged viability and special germination requirements (Andrews, 1945;Brown & Edwards, 1945;Brown, 1965;Egley, 1972). In order to germinate, seeds must be conditioned in a warm moist environment for several days and then exposed to an exogenous germination stimulant (Brown & Edwards, 1945). The huge reserves of seed in the soil, coupled with prolonged viability and special germination requirements, together with environmental variables, make Striga a difficult weed to control (Ibrahim et al, 1985).…”

Section: Introductionmentioning

confidence: 99%

Induction of Striga seed germination by thidiazuron

1992

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Summary: Résumé: Zusammenfassung Thidiazuron at 0.1 to 10 mg 1−1 induced concurrent germination and haustorium initiation in Striga asiatica (L.) Kuntze and S. hermonthica (Del.) Benth, but it had no effects on S. gesnerioides (Willd.) Vatke. Both millet and sorghum strains of S. hermonthica were equally responsive. The response of Striga seeds to thidiazuron increased with conditioning. Early applications of the compound induced some germination, but had adverse effects on the conditioning process. Induction de la germination des graines de Striga par le thidiazuron Le thidiazuron de 0,1 à 10 mg 1−1 a induit de façon conjointe le germination et l'initiation d'haustoria chez Striga asiatica et S. hermonthica, mais n'a pas eu d'effet sur S. gesnerioïdes. Les souches de S. hermonthica liées au millet et au sorgho ont un comportement équivalent. La réponse des graines de Striga au thidiazuron a augmenté par conditionnement préalable. Des applications précoces de produit ont induit quelques germinations, mais ont eu des effets contraires sur Ie processus de conditionnement. Einleitung der Samenkeimung bei Striga‐Arten durch Thidiazuron Mittels Thidiazuron‐Lösungen von 0,1 bis 10 mg 1−1 konnten eine gleichzeitige Keimung und Ausbildung der Haustorien bei Striga asiatica (L.) Kuntze und S. hermonthica (Del.) Benth. herbeigeführt werden, nicht jedoch bei S. gesnerioides (Willd.) Vatke. Der Rispenhirsen‐und der Sorghum‐Typ von S. hermonthica reagierten in gleichem Maße. Konditionierung der Striga‐Samen förderte die Wirkung von Thidiazuron. Frühe Anwendung des Wirkstoffs führte zu einer geringen Keimung, beeinträchtigte jedoch die Konditionierung.

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Effects of Thiourea and Allylthiourea on the Germination of the Seed of Striga lutea

Cited by 26 publications

References 6 publications

La relation entre le Striga hermonthica et ses hôtes: une synthèse

La relation entre le Striga hermonthica et ses hôtes: une synthèse

THE PARASITISM OF STRIGA HERMONTHICA BENTH. ON LEGUMINOUS PLANTS

Induction of Striga seed germination by thidiazuron

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