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To improve the salt tolerance of Genovese cultivar of sweet basil (Ocimum basilicum L.) plants, an experiment was conducted to evaluate the impact of certain growth substances (salicylic acid, seaweed extract, dry yeast and moringa leaf extract) on growth, volatile oil percentage and yield as well as chemical constituents under saline water irrigation stress conditions (control, 1000, 2000 and 4000 ppm NaCl). The obtained results revealed that the higher salinity levels (2000 and 4000 ppm NaCl) caused significant decreases in vegetative growth measurements of basil plants compared to control and the lowest salinity level (1000 ppm NaCl). Maximum reduction was observed at 4000 ppm NaCl which showed higher increase of the total phenolics and free proline contents. All recoded parameters were enhanced for plants grown under 1000 ppm NaCl. Seaweed extract was superior than other treatments in enhancing the plant tolerance to salinity which appeared in the significantly increasing of growth and volatile oil content of basil. Phenolics and proline contents were increased with salicylic acid treatment comparing with other ones. The best combination recommended as a result of the current study is treating basil plants with seaweed extract under low salinity level (1000 ppm) for improving the growth and volatile oil parameters.

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This study was conducted in the two successive seasons of 2005/2006 and 2006/2007 at the Experimental Farm of Floriculture, Faculty of Agriculture, Assiut University. The aim of this study was to investigate the effect of three rates of each of nitrogen (0, 50 and 100 kg/fed.), active dry yeast (0, 2 and 4 g/l) and tryptophan (0, 50 and 100 ppm) on the growth, fruit and oil yield and chemical composition of fennel plants. The obtained results revealed that the application of nitrogen, active dry yeast and/or tryptophan resulted in a significant increase in vegetative growth, fruit and oil yield as well as fruit content of total carbohydrates, N, P and K compared to the controls. It was interesting to observe that the application of active dry yeast at 4 g/l as biofertilizer with 100 ppm tryptophan as organic nitrogenous source gave nearly equal results to those obtained with the high level of mineral nitrogen fertilizer (100 kg N/fed.) alone. Also, the application of active dry yeast at 4 g/l or tryptophan at 100 ppm combined with 50 kg N/fed. resulted in a significant increase in all studied parameters compared to the high level of nitrogen alone. The maximum vegetative growth and flowering, fruit and oil yield as well as fruit nutrient content were obtained from the combined treatment of 50 kg N/fed. + 2 or 4 g/l active dry yeast + 50 ppm tryptophan.

Potassium (K) levels are decreasing worldwide in agricultural soils, and K deficiency is becoming a major issue. Study on damask rose response to K application is scarce. Furthermore, despite its importance in the cell division, photosynthesis and protein synthesis, there is a lack of published reports on plant responses to zinc (Zn) application. Further research is required to understand the damask rose's response to both elements. This study investigated the effects of K and Zn foliar application on the vegetative growth, flower yield, and volatile oil content and composition of damask rose. K and Zn nutrition was applied either individually or combined as K2SO4 and ZnSO4 at 0.5 or 1.0%. Foliar application of K2SO4 and ZnSO4 was applied with a manual pump four times in each growing season, the first at the beginning of stem elongation and leaf formation, and then at two-weekly intervals. Results showed that K and/or Zn treatments significantly improved the growth characters, flower yield, relative water content (RWC), stomatal conductance, and essential oil content and composition such as linalool, nerol, citronellol, geraniol, and nonadecane. The chlorophyll content, total soluble sugars (TSS), and protein content also increased, but free amino acid content decreased, suggesting that the distribution of nitrogenous compounds (between amino acids and proteins) and their transformation were influenced by K and Zn supply. Individual applications of K or Zn increased the N, P, K, and Zn contents in damask rose leaves, relative to the control, which increased further with combined applications of K and Zn. Results suggest that foliar application of K and/or Zn could be part of the damask rose fertilization program to provide plants with the optimum level of nutrition for improving the quantity and quality of flowers and essential oil yields.

The current study was conducted to evaluate the effects of indole-3-butyric acid (IBA) at 100 ppm with or without biostimulants (Agrobacterium rhizogenes, seaweed extract and coconut water) as either a spray or drench for 3 minutes or 1 hour on rooting and growth parameters of three cutting types (tip, middle and basal) of Conocarpus erectus L. The data showed that the rooting percentage, root and vegetative characteristics of rooted cuttings were significantly increased by all treatments of IBA and/or biostimulants compared to the untreated cuttings. The individual treatments of seaweed extract and coconut water were more effective than IBA or A. rhizogenes alone. Seaweed extract as drench with or without IBA surpassed those of seaweed extract treatments as spray. Besides, the response of cuttings treated with coconut water for 1 hour was better than coconut water for 3 min. Tip cuttings were significantly better than the middle and basal ones, especially in relation to rootability of cuttings. Maximum rooting percentage and shoot characteristics of plants were obtained from tip cuttings treated with IBA + coconut water for 1 hour, followed by IBA + seaweed extract as drench. The highest rooting percentage was associated with high endogenous levels of phenols, indole acetic acid (IAA) and gibberellic acid (GA) as well as the lowest abscisic acid (ABA) level in cutting tissues and the anatomical structure of rooted cuttings. So, it can be recommended treating tip cuttings of C. erectus with either coconut water for 1 hour or seaweed extract as drench combined with IBA for enhancing the rooting percentage, root and shoot growth parameters as well as content of endogenous root promoting substances.

Bio-stimulants play a vital role in the sustainable development of horticultural crops. The aim of this study was to assess the effect of synthesis stimulator (salicylic acid) and bio-stimulants (moringa extract, seaweed extract) on growth, yield and quality of Roselle, Hibiscus sabdariffa L., plants. The recorded growth parameter included plant height, number of lateral branches per plant, branch diameter, and leaf area. For yield traits, the calyxes' fresh and dry weight was recorded. Leaf pigments included chlorophyll a, b, and carotenoids. Anthocyanin content in calyxes was measured. The experiment was conducted during 2018 and 2019 seasons, and was designed in completely randomized system. The results showed that application of bio-stimulants showed positive effects on all traits, and the best results were shown under treatment of seaweed, followed by moringa leaves extract. There were positively associations of calyxes yield and its anthocyanin content with other growth traits and photosynthetic pigments. These results highlighted the important role of biostimulants, especially seaweed extract, as a bioactive stimulant. Therefore, it is recommended to include seaweed extract in fertilization programs for achieving sustainable production system of such crops.

The present study was conducted to evaluate the influence of rooting media (clay, peat moss + sand, peat moss + perlite and vermiculite), cutting types (tip, middle and basal) and different concentrations of indole-3-butyric acid (control, 50, 100 and 200 ppm IBA) on the rooting and growth of Conocarpus erectus L. stem cuttings. The experiment was laid out in a split-split-plot design, with three replicates. The obtained results showed that vermiculite was the best rooting medium used for improving the rooting percentage, root number, root length, stem length, branch number and leaf number per rooted cutting, followed by peat + perlite (1:1 in v/v) and peat + sand (1:1 in v/v), respectively comparing with clay soil which recorded the lowest values. The tip cutting was superior to the middle and basal ones in all rooting media used, especially in vermiculite medium. Among IBA concentrations used, cuttings treated with IBA at 100 ppm produced significantly better rooting (42.9%) than 50 ppm (36.3%), 200 ppm (36.0%) and untreated cuttings (23.1%). The greatest rooting percentage (95.0%) and the best root and growth characteristics as well as the highest endogenous contents of phenols, indole acetic acid (IAA) and the lowest abscisic acid (ABA) contents were obtained from tip cuttings treated with IBA at 100 ppm and planted in vermiculite substrate. Moreover, the combined treatment of 100 ppm IBA and vermiculite substrate significantly improved the rooting percentage, root and growth measurements of middle and basal cuttings as well as gave the highest C/N ratio in basal cutting tissues compared to the same cutting types combined with the other rooting media and IBA concentrations. Hence, it could be recommended to treat the different types of C. erectus stem cuttings with IBA at 100 ppm and planting in vermiculite medium for improving rooting, quality and growth of cuttings.