Abstract
Two pots experiments were conducted at the Experimental Farm of El-Qassasin Horticultural Research Station, Agricultural Research Center, Ismailia Governorate, Egypt, during two successive seasons of 2016/2017 – 2017/2018, to investigate the effect of potassium silicate at (0, 4, 6, and 8 cm3/l) as a foliar spray under different levels of water salinity (tap water, 1000, 2000 and 3000 ppm) on Calendula officinalis L. plant. The experiment was performed in complete randomized block design as factorial experiment with 3 replicates. The obtained results cleared that using salinity levels decreased growth parameters (plant height, number of branches/plant, fresh and dry weights of herb/plant), flowering parameters (flower diameter, number of flowers/plant, fresh and dry weight of flowers (g/plant) during eight cuts and fresh and dry weight of flowers (g/plant/season)) and chemical constituents (chlorophyll a, chlorophyll b, carbohydrate and carotenoid contents) compared to control. Moreover, the highest values in these parameters were registered by potassium silicate at 8 cm3/l concentration. Proline content increased in leaves with using saline water at 3000 ppm + potassium silicate at 8 cm3/l. Generally, it could be concluded that potassium silicate at 8 cm3/l, showed a uniform impact in alleviating inhibition of Calendula officinallis L. plant growth and productivity under moderate salinity stress condition.
Highlights
Hydroponic culture became the new modern agricultural technology this years; the spreading of pathogens considers the major problem especially in closed system technique (Nosir, et al 2009)
The effect of F. oxysporum f. sp. gladioli on the major secondary metabolites secreted by biocontrol strain of T. harzianum in Potato Dextrose Broth (PDB) cultures were investigated and quantified; followed by investigating the effect of the previous microorganisms on T. harzianumsecondary metabolites secreted in Gladiolus grandiflorus corms tissues under controlled conditions
Thin Layer Chromatography (TLC), Liquid chromatography Mass spectroscopy (LC/MS), and Nuclear Magnetic Resonance (NMR) techniques were used in this study to determine the major secondary metabolites
Summary
Hydroponic culture became the new modern agricultural technology this years; the spreading of pathogens considers the major problem especially in closed system technique (Nosir, et al 2009). Secondary metabolites secreted by Trichoderma spp. include volatile and non-volatile antifungal substances, such as 6-n-pentyl-6H-pyran-2one (6PP), gliotoxin, viridin, harzianopyridone, harziandione and peptaibols (Reino et al, 2008) The activities of these metabolites against soilborne plant pathogens have long been studied (Ghisalberti and Sivasithamparam, 1998). The involvement of secondary metabolites produced by Trichoderma spp. in the activation of plant defence mechanisms and the regulation of plant growth was recently investigated, using tomato and oil-seed rape seedlings treated with harzianolide and 6PP isolated from T. harzianum, followed by infection with spore suspensions of Botrytis cinerea and Leptosphaeriamaculans, respectively In both host plant species, a reduction in disease symptoms was observed, on 6PP-treated plants. The aims of the work presented here were to develop an improved understanding of the roles of major secondary metabolites produced by T. harzianum in the interaction between T. harzianum,F. oxysporum f. sp. gladioli
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