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Mineral nutrient concentration influences sunflower infection by broomrape (Orobanche cumana)
Mineral nutrient concentration influences sunflower infection by broomrape (Orobanche cumana)
- Source :
- Botany. September, 2010, Vol. 88 Issue 9, p839, 11 p.
- Publication Year :
- 2010
-
Abstract
- Orobanche cumana Wallr., a root parasitic angiosperm, causes severe yield losses in Helianthus animus L. (sunflower) in Europe. Until now, the only effective method of controlling this parasite has been the use of resistant sunflower genotypes. Broomrape resistance is, however, poorly understood even though previous studies have revealed several defence mechanisms. The study of a susceptible (2603) and a resistant ( LR1 ) sunflower genotype in hydroponic co-culture showed that the degree of infection by broomrape is influenced by the concentration of nutrients in the growth medium. For the susceptible genotype, an increase in broomrape necrosis was observed when the nutrient concentration was increased. In the resistant genotype LR1, the rate of infection was reduced by increasing the concentration of mineral nutrients, measured as a decrease in broomrape attachments and a lack of underground stem development. When sunflowers were cultivated in full-strength medium, these findings correlated with a lower l4C incorporation in broomrape and a change in carbon allocation to host plant organs with a reinforced 'shoot apex sink strength'. Results demonstrated that in controlled conditions, the nutrient concentration directly affects sunflower resistance potential towards broomrape. Key words: broomrape, Helianthus, holoparasile, nutrition, resistance to Orobanche cumana, sunflower. L'Orobanche cumana Wallr., plante parasite racinaire, provoque de nombreux degats sur les cultures de tournesol (Helianthus annuus L.) dans toute l'Europe. Jusqu'a aujourd'hui, la seule methode de lutte efficace reste l'utilisation de genotypes resistants. Cependant, les mecanismes de resistance a l'orobanche restent encore meconnus. bien que des etudes precedentes aient demontre l'existence de plusieurs mecanismes. L'etude de genotypes de tournesol sensible (2603) et resistant ( LR1 ) en culture hydroponique a permis de mettre en evidence que la concentration du milieu de culture modifie le niveau d'infestation du tournesol par l'orobanche. Pour le genotype sensible (2603), le nombre de parasites necroses augmente avec la concentration du milieu de culture. Pour le genotype resistant (LR1), l'augmentation de la concentration du milieu de culture diminue l'inTestation en diminuanl le nombre d'orobanehes Tixees sur les racines et en limitant leur developpement ulterieur. Lorsque l'on cultive les tournesols dans le milieu non dilue, l'allocation de radiocarbone dans la plante se modifie avec tin accroissement de la force puits de l'apex caulinaire, alors que l'incorporation de [.sup.l4]C est reduite dans les orobanches. Notre etude demontre qu'en milieu controle, la concentration en nutriments influe directement sur le potentiel de resistance du tournesol a l'orobanche. Mots-cles : orobanche, Helianthus, holoparasile, nutrition, resistance a l'Orobanche cumana, tournesol.<br />Introduction Within parasitic plants, some Orobanche species induce severe damage in several crops. Orobanche cumana Wallr. (broomrape), a root holoparasile, causes heavy yield losses in sunflower seed production in Europe, [...]
Details
- Language :
- English
- ISSN :
- 19162790
- Volume :
- 88
- Issue :
- 9
- Database :
- Gale General OneFile
- Journal :
- Botany
- Publication Type :
- Academic Journal
- Accession number :
- edsgcl.239530954
- Full Text :
- https://doi.org/10.1139/B10-057