Bayoud disease of date palm: ultrastructure of root infection through pneumatodes

1986 ◽  
Vol 64 (8) ◽  
pp. 1703-1711 ◽  
Author(s):  
Rosa Belarbi-Halli ◽  
François Mangenot

Young axenically grown plants of date palm, Phoenix dactylifera cv. Deglet-nour, were inoculated with Fusarium oxysporum Schl. f. sp. albedinis (Killian et Maire) Gordon, using conidia applied either on the pneumatode-free main root or on the pneumatodes of rootlets. After incubation for 15 days, infection was successful only in the latter case. The fungus grew inside the aerenchyma and clung tightly to the cell walls, the wartlike outgrowths, and the matrix present in the intercellular spaces. These structures were more or less altered in the presence of the hyphae. The fungus proceeded both intercellularly and intracellularly through the cortex. A dense hyphal sheet was observed facing the suberized endodermis, but the fungus somehow made its way into the stele. Penetrations of thick-walled cells commonly occurred through pits. Root colonization was slower toward the root apices than toward the base. After 15 days, the fungus was present at least 8 cm above the inoculation point at the base of the root.


Author(s):  
Eimad Dine Tariq Bouhlali ◽  
Mgal Derouich ◽  
Houria Ben-Amar ◽  
Reda Meziani ◽  
Adil Essarioui

Abstract Background “Bayoud” disease caused by Fusarium oxysporum f. sp. albedinis (Foa) poses a serious threat to date palm (Phoenix dactylifera L.) in Morocco. However, research studies performed to discover biological methods to control this disease remain limited. The present study has set objectives to determine antifungal activity of five plants extracts (Acacia cyanophylla, Cupressus atlantica, Eucalyptus torquata, Nerium oleander, and Schinus molle) against Foa and link this effect to their content in polyphenols and flavonoids as well as their antioxidant properties. Results Plant extracts showed significant differences (p < 0.05) regarding their antifungal activity. The extracts of E. torquata and C. atlantica showed the strongest antifungal effect resulting in the inhibition of mycelial growth, sporulation, and spore germination in a dose-dependent manner. In addition, there were significant differences among the examined plant extracts in respect to their total polyphenols (1.536–7.348 g GAE/100 g DW), flavonoids (0.986–5.759 g RE/100 g DW), and antioxidant properties measured by Trolox equivalent antioxidant capacity (TEAC) (7.47–38.97 mmol TE/100 g DW) and ferric-reducing antioxidant power (FRAP) assay (8.95–47.36 mmol TE/100 g DW). Moreover, the antifungal potential of plant extracts was found to be moderately to strongly correlated with their polyphenol and flavonoid contents as well as their antioxidant activity, implying that the effective inhibitory activity of these plant extracts is partly due to their richness in antioxidative secondary metabolites. Conclusion Our findings shed further light on plants as a-yet-untapped resource of bioactive compounds and constructed the foundation for the development of new biological approaches to best manage Bayoud disease.



Author(s):  
Hakima Belaidi ◽  
Fawzia Toumi-Benali ◽  
Ibrahim Elkhalil Benzohra

Background: This work has the objective to biocontrol the bayoud disease of date palm caused by the fungus Fusarium oxysporum f. sp. albedinis (Foa), is the major disease in Algerian palm groves of south western region. This in vivo biocontrol was done on date palm variety Deglet-Nour, using two antagonistic fungi species, Trichoderma harzianum and Aspergillus flavus.Methods: Twenty Foa isolates obtained from isolation of the spines carrying the typical symptoms of Bayoud disease were used. Two strains T. harzianum and A. flavus, were isolated from rhizosphere soils of the date palm trees. Using the greenhouse screening test, which was carried out on 3-4 month-old date palm seedlings at the rate of 5 ml of inoculum suspension.Result: A statistical analysis showed a significant (P less than 0.05), difference of Deglet-Nour seedlings reactions against Foa isolates and antagonistic fungi were observed. All date palm trees present susceptibility against Foa until the total mortality of seedlings. The biocontrol test showed that two antagonists showed different reaction, with the complete resistance for seedlings treated by T. harzianum with the mortality rate (rm%) reduced at 100%, while, the second antagonist A. flavus reduced the rm% at 25%. We can apply of these antagonistic fungi to protect our groves contaminated by Bayoud disease and also contain this susceptible commercial variety.



2012 ◽  
Vol 55 ◽  
pp. 7-15 ◽  
Author(s):  
Abdelhi Dihazi ◽  
Fatima Jaiti ◽  
WafaTaktak ◽  
Olfa kilani-Feki ◽  
Samir Jaoua ◽  
...  


1988 ◽  
Vol 66 (1) ◽  
pp. 89-93 ◽  
Author(s):  
M. Baaziz ◽  
M. Saaidi

Two types of crude extracts were obtained from 10 cultivars of date palm (Phoenix dactylifera L.); the Tris buffer extracts from acetone powder were assayed for peroxidase activity and the phosphate buffer extracts were subjected to polyacrylamide gel electrophoresis. The gels were stained for esterase activity using α-naphthylacetate and α-naphthylbutyrate as substrates. The cultivars were divided into four sets on the basis of their esterase isoenzyme phenotypes. These sets were further separated into their individual cultivars on the basis of peroxidase activities. The results are discussed with respect to the possible relationship of the peroxidase activity in the vascular fusariosis of date palm (Bayoud disease). This study has potential for practical application; however, some additional refinements in procedures appear necessary to reduce extraction time.





2019 ◽  
Vol 11 (1) ◽  
pp. 93-100
Author(s):  
T Ljubka ◽  
O Tsarenko ◽  
I Tymchenko

The investigation of macro- and micromorphological peculiarities of seeds of four species of genus Epipactis (Orchidaceae) of Ukrainian flora were carried out. The genus Epipactis is difficult in the in in taxonomic terms and for its representatives are characterized by polymorphism of morphological features of vegetative and generative organs of plants and ability of species to hybridize. The aim of the research was to perform a comparative morphological study of seeds of E. helleborine, E. albensis, E. palustris, E. purpurata and to determine carpological features that could more accurately identify species at the stage of fruiting. A high degree of variation in the shape of the seeds in different populations within the species and overlap of most quantitative carpological characteristics of studied species are noted. There were no significant differences in micromorphological features of the structure of the testa at species or population level. The reticulate surface of the testa is characteristic of all species, the cells of testa are mostly elongated, penta-hexagonal, individual cells almost isodiametric-pentagonal. From the micropillary to the chalasal end, a noticeable change in the shape and size of the seed coat cells is not observed. There are no intercellular spaces, the anticlinal walls of adjacent cells are intergrown and the boundaries between them become invisible. The outer periclinal walls have a single, mainly longitudinal thin ribbed thickenings. Anticlinal cell walls are thick, dense, smooth. The longitudinal Anticlinal walls are almost straight, transverse - straight or sometimes curved in some cells. Epicuticular deposits on the periclinal walls are absent. It is concluded that the use of macro and micromorphological characteristics of seeds of these species for clearer diagnosis at the stage of fruiting is low informative.



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