To investigate early salt acclimation mechanisms in a salt-tolerant poplar species (Populus euphratica), the kinetics of molecular, metabolic, and physiological changes during a 24-h salt exposure were measured. Three distinct phases of salt stress were identified by analyses of the osmotic pressure and the shoot water potential: dehydration, salt accumulation, and osmotic restoration associated with ionic stress. The duration and intensity of these phases differed between leaves and roots. Transcriptome analysis using P. euphratica-specific microarrays revealed clusters of coexpressed genes in these phases, with only 3% overlapping salt-responsive genes in leaves and roots. Acclimation of cellular metabolism to high salt concentrations involved remodeling of amino acid and protein biosynthesis and increased expression of molecular chaperones (dehydrins, osmotin). Leaves suffered initially from dehydration, which resulted in changes in transcript levels of mitochondrial and photosynthetic genes, indicating adjustment of energy metabolism. Initially, decreases in stress-related genes were found, whereas increases occurred only when leaves had restored the osmotic balance by salt accumulation. Comparative in silico analysis of the poplar stress regulon with Arabidopsis (Arabidopsis thaliana) orthologs was used as a strategy to reduce the number of candidate genes for functional analysis. Analysis of Arabidopsis knockout lines identified a lipocalin-like gene (AtTIL) and a gene encoding a protein with previously unknown functions (AtSIS) to play roles in salt tolerance. In conclusion, by dissecting the stress transcriptome of tolerant species, novel genes important for salt endurance can be identified.

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N EW agriculture practices are required for developing water use efficiency. Mulching as a target for that goalhas not been adequately quantified. The aim of this work was to clarify the role of rice straw mulchingin reserving water under surface irrigation and quantify its application benefits on yield and quality of king ruby grape vineyard grown in Delta Nile of Egypt during 2017 and 2018 seasons. The experimental layout included six treatments T1, T3 and T5 for three irrigation regimes which introduced control or zero, 25% and 50% of restriction irrigation water. T2, T4 and T6 introduced the mulching application within the previous irrigation regimes. The irrigation regime started at veraison phase (pre maturity stage) from May 2017 till end of July (time of harvest) and straw mulches were applied at rate 5 kg/m 2 , and it was renewed in 2018 season. Soilbulk density (BD), infiltration rate (IR) and NPK uptake were looked up. Growth and qualities attributes were figured out as a reflection affect by treatments under investigations. Results highlighted the role of mulching in keeping soil moisture under severe drought stress, 50% of restriction irrigation water (T6) similar to unstressed, control (T1) subsequently the most measured parameter of soil, growth and quality were similar in both treatments. These findings suggest the application of T6 (50% of restriction irrigation water) treatment as a target recommendation for saving 50 % of irrigation water without yield reduction and with good qualities.

I NCREASING saline-sodic soils area as a result of climatic change, wrong agriculture practices and unsuitable of nutrition sources were lead to malnutrition and caused low productivity and quality of citrus. The study focused on gypsum and compost application in the proper rates for coping with such variable parameters. The trial carried out during 2017 and 2018 seasons on Washington navel orange trees (Citrus sinensis L., Osbek) grafted on sour orange (Citrus aurantium L.). Six application treatments were examined for the purpose of the study, i.e., T1: control, T2: compost at 10 tons/ fed, T3: compost at 15 tons/ fed, T4: gypsum at 10 tons/ fed, T5: T4+T2 and T6: T4+T3. Field capacity (FC), Permanent wilting point (PWP), available water (AW), soil moisture and soil total content of NPK as indicators of soil parameter for application treatments were looked up. Growth parameters such shoot length, number of shoots/branch, number of leaves/shoot and leaf area, yield attributes such fruit set, fruit cracking, peel thickness, total tree yield (Kg), fruit juice volume, TSS, acidity, total sugars and vitamin C and leaf nutritional content of N, P, K, Ca and Mg were also determined. Results showed that T6 gave the highest results followed by T5, T4, T3 and T2 whereas T1 was the lowest ones for all parameters under investigations. The study aimed and recommends gypsum at 10 tons/ fed + compost at 15 tons/ fed for ameliorating saline-sodic soil and improving growth, yield and quality of Washington navel orange under such conditions.