THE EFFECT OF THE FLORAL APPLICATION OF GIBBERELLIC ACID ON UNPOLLINATED INFLORESCENCES OF THE DATE PALM CULTIVAR ASSIANE (Phoenix dactylifera L.): A CASE STUDY OF FIGUIG OASIS, MOROCCO

The objective of the present study was to evaluate the effect of Gibberellic Acid in mitigate the phenomenon of parthenocarpy and improve the fruit set in the date palm cultivar Assiane at Figuig Oasis in Morocco. For this, four different concentrations of Gibberellic Acid (GA3) viz., 5, 50, 100, and 200 ppm were applied on unpollinated inflorescences in two phases. The first dose of GA3 is applied at the time of spadices burst while the second one is applied after the seven days of the first one. The results obtained from the study showed that the application of gibberellic acid on unpollinated female inflorescences had a significant effect on the removal of parthenocarpy which resulting in the higher normal-looking fruits with normal seed and by promoting the maturity of parthenocarpic fruits. In the case of rate of thinning, the application of GA3 @ 5-100 ppm enhanced the flower drop, while the application at higher concentration i.e. 200 ppm promotes the retention and development of flowers. Further, the analysis of the ripe fruits sugars content by high performance liquid chromatography (HPLC) suggests that the application of GA3 did not have any significant effect on the sugar content and these treatments are not significantly different from the fruits of pollinated flowers

Elaboration and Characterization of ZnO/FTO thin films under different concentrations - Study dedicated to the photovoltaic systems - Study d

© 2020 IEEE. This paper presents an elaboration of thin films dedicated to photovoltaic systems. Zinc oxide (ZnO) on fluorine tin oxide (FTO) coated glass substrates are one of the best semiconductors oriented to solar cell preparations. In this study, the ZnO solution is performed with some sol concentration (0.1 M to 0.5 M) to verify its effect on thin-film samples. On the other hand, samples prepared are analyzed and characterized in structural and the optical properties using different techniques as ultraviolet-visible (UV-vis) spectrometry, Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). This work showed the variation of the energy gap (Eg) values. The Eg values allow us to ensure good solar cells. In this study, the thin films prepared showed that the energy gap values are ranged between 3.29 eV and 3.4 eV. These results led us to confirm the possibility of having an easy passage of the electrical current. In addition, the transmittance spectra of the ZnO/FTO thin films showed an average of ~75% in the visible region and presented sharp absorption edges at 375 nm. The experimental preparation ensures a good decision about electrical energy production which based on the photovoltaic systems

Effects of climate change on the rate of parthenocarpy of date palm (Phœnix dactylifera L.): Case of the cultivar Assiane in the oasis of Figuig

Depuis 2015, la parthénocarpie a réduit la production dattière du cultivar dominant de l’oasis de Figuig. La maitrise de la pollinisation traditionnelle par les Figuiguis laisse supposer que des liens de causalité devrait exister entre ce phénomène chez le cultivar Assiane et les changements climatiques. Pour vérifier cette hypothèse, nous nous sommes basés sur l’étude de l’effet de l’ensachage des inflorescences, après leur pollinisation, avec trois types de voiles en polyéthylène (P 17 g/m², P 30 g/m² et P 60 g/m²). L’analyse des résultats a montré que les phases de la pollinisation et de la nouaison sont très vulnérables à la température. En effet, l’émergence précoce des inflorescences femelles à partir du mois de janvier et parfois en mi-décembre rend la mise à fruits difficile à cause des basses températures qui sévissent durant cette période. La protection des inflorescences par les voiles a permis de créer des conditions favorables à la germination des grains de pollen grâce aux températures favorables qui ont été enregistrées au stade fin-floraison. En effet, les voiles P17, P30 et P60 ont permis des taux de nouaison supérieurs à celui du témoin de 21,8; 23,4 et 30,4% et une amélioration de la production dattière de 70,3; 137,8 et de 159,4% respectivement. Mots clés: Oasis de Figuig, Cultivar Assiane, Parthénocarpie, Changements climatiques, basses températures, Nouaison, Voiles en polyéthylèneDespite the mastery of the pollination operation by Figuigui date palm farmers, parthenocarpy has led, since 2015, to an alarming drop in date production of the Assiane cultivar, which represents more than 51% of the oasis' plants. The present research aims to verify the hypothesis of the existence of causal links between parthenocarpy in date palms and the climatic changes in the Figuig oasis. To achieve this objective, we conducted a study on the effect of bagging the inflorescences of cultivar Assiane after their pollination, with three types of polyethylene veils (P17g/m², P30g/m² and P60g/m²), on the rate of fruit set and parthenocarpy. The analysis of the results showed, first, that the pollination and fruit setting phases are very vulnerable to temperature. Indeed, the low temperatures during the three flowering stages made fruiting difficult. Furthermore, the bagging of the inflorescences allowed to create favorable conditions for the germination of pollen grains thanks to the favorable temperatures that were recorded at the end-flowering stage. Clearly, the P17, P30 and P60 veils allowed higher fruit set rates than the control of 21.8, 23.4 and 30.4% and an improvement in date production of 70.3, 137.8 and 159.4% respectively. Keywords: Oasis of Figuig, Cultivar Assiane, Climate change, Parthenocarpy, Fruit set, low temperature, Polyethylene sail

Effect of heat treatment on the photocatalytic activity of alpha-Fe2O3 nanoparticles: towards diclofenac elimination

alpha-Fe2O3 nanoparticles were synthesized via a straightforward method. XRD, FTIR, SEM, ESR, and DRS techniques investigated the influence of various calcination temperatures on the crystal structure, optical, and photocatalytic properties of the samples. The obtained results demonstrated that the average crystallite size increased with the increase in the calcination temperature. Measured and computed optical properties were in accordance and the bandgap energy decreased with the increase in the calcination temperature. The highest photocatalytic degradation efficiency for diclofenac (DCF) was obtained with the sample calcinated at 300 degrees C (96%). The photocatalytic process occurs because of the presence of OH center dot radicals. The addition of H2O2 led to the inhibition of OH center dot radicals that H2O2 scavenged

Calculations of the molecular interactions in 1,3-dibromo-2,4,6-trimethyl-benzene: which methyl groups are quasi-free rotors in the crystal?

International audienceDibromomesitylene (DBMH) is one of the few molecules in which a methyl group is a quasi-free rotor in the crystal state. Density functional theory calculations - using the Born-Oppenheimer approximation (BOa) - indicate that in isolated DBMH, Me4 and Me6 are highly hindered in a 3-fold potential V-3 > 55 meV while Me2 symmetrically located between two Br atoms has a small 6-fold rotation hindering potential: V-6 similar to 8 meV. Inelastic neutron scattering studies have shown that this is also true in the crystal, the Me2 tunneling gap being 390 mu eV at 4.2 K and V-6 similar to 18 meV. In the monoclinic DBMH crystal, molecules are packed in an anti-ferroelectric manner along the oblique a axis, favoring strong van der Waals interactions, while in the corrugated bc planes each molecule has a quasi hexagonal environment and weaker interactions. This results in the nearby environment of Me2 only being composed of hydrogen atoms. This explains why the Me2 rotation barrier remains small in the crystal and mainly 6-fold. Using the same potentials in the Schrodinger equation for a -CD3 rotor has allowed predicting a tunneling gap of 69 mu eV for deuterated Me2 in very good agreement with inelastic neutron scattering measurements. Therefore, because of a rare and unexpected local symmetry in the crystal, the Me2 rotation barrier remains small and 6-fold and hydrogen nuclei are highly delocalized and not relevant to the Born-Oppenheimer approximation. This and the neglect of spin states explain the failure of density functional theory calculations for finding the rotation energy levels of Me2

Structural and Magneto-Electrical Properties of Bi2-xSmxSr2CaCu2O8 + δ High Tc Superconductor Prepared by Pechini Method

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