Sufficient production, consistent food supply, and environmental protection in urban +settings are major global concerns for future sustainable cities. Currently, sustainable food supply is under intense pressure due to exponential population growth, expanding urban dwellings, climate change, and limited natural resources. The recent novel coronavirus 2019 (COVID-19) pandemic crisis has impacted sustainable fresh food supply, and has disrupted the food supply chain and prices significantly. Under these circumstances, urban horticulture and crop cultivation have emerged as potential ways to expand to new locations through urban green infrastructure. Therefore, the objective of this study is to review the salient features of contemporary urban horticulture, in addition to illustrating traditional and innovative developments occurring in urban environments. Current urban cropping systems, such as home gardening, community gardens, edible landscape, and indoor planting systems, can be enhanced with new techniques, such as vertical gardening, hydroponics, aeroponics, aquaponics, and rooftop gardening. These modern techniques are ecofriendly, energy- saving, and promise food security through steady supplies of fresh fruits and vegetables to urban neighborhoods. There is a need, in this modern era, to integrate information technology tools in urban horticulture, which could help in maintaining consistent food supply during (and after) a pandemic, as well as make agriculture more sustainable.

Date palm is the primary agricultural crop in Oman, and it constitutes 80 % of all fruit crops produced and 50 % of the total agricultural area in the country. Oman is the eighth largest producer of dates in the world with an average annual production of 260,000 mt per annum. There are approximately more than over seven million date palms and 250 cultivars in cultivation, primarily in the northern governorates of the sultanate. However, around 70 % of the total date production is harvested from only 10 cultivars, and a small fraction (2.6 %) of the total date production is exported. Only half of the dates produced are used for human consumption, with the other half being utilized primarily for animal feed or considered surplus and wasted. Dates are mainly harvested for fresh fruit consumption; however, alternative uses such as date syrup, date sugar, and other by-products can also be found in the local market. Dubas bug and red palm weevil are the dominant biotic factors that affect date quality and yield in Oman. Traditional methods of cultivation, small farm size, enough labor available, and poor postharvest handling and marketing are the main issues that face date palm production in Oman. New plantlets are produced from tissue culture with a primary focus on superior cultivars that are kept, among other cultivars, in the only date palm ex situ gene bank in the interior of Oman. Enhancing fruit quality by optimizing fruit size and nutritional content and rapid cultivar selectivity based on molecular techniques for better or improved commercial cultivars will increase the marketability of Omani dates. Furthermore, employing modern orchard layouts and mechanization of the labordependent cultural practices such as irrigation, pruning, pollination, and harvesting is vital for the sustainable and profi table production of dates in Oman.

The date fruit is a primary component of the human diet in many countries with arid and semiarid climates. The present study reflects the relationship of different biochemical attributes with progressive date fruit developmental stages. The study involved eight date palm (Phoenix dactylifera L.) cultivars from Pakistan examined at three different edible stages of dates (khalal, rutab and tamar). The antiradical efficiency (2.14-0.36), antioxidant enzymes (catalase and peroxidase), total phenolic contents (468.99-108 mg GAE/100g, FW) and the soluble protein contents (5.73-2.75 g/100g) were higher in higher at khalal and thereafter, but declined at fully ripened (tamar) stage. Moreover, glucose (16.92-31.66%) and fructose (15.25-30.58%) have lower quantity at khalal and higher quantity at tamar stage, whereas non-reducing (sucrose) sugars were present only at khalal and rutab stage fruits. Makran and Chohara cultivars revealed best overall values in examined compounds. Our results revealed that variation in different biochemical attributes is mainly depended on the difference in fruit maturity stage and cultivar. Cultivars exhibiting high values of beneficial biochemical attributes may be considered for the expansion of date palm cultivation.

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A study was conducted to investigate the morphological, physiobiochemical, enzymatic, and ionic differences among four cultivated citrus (Citrus sp.) rootstocks with different salt tolerances. Two salt-tolerant rootstocks [Rangpur lime (C. limonia) and Rubidoux (C. trifoliata)] and two salt-sensitive rootstocks [Carrizo citrange (Citrus sinensis × C. trifoliata) and Sanchton citrumello (C. trifoliata × C. paradisi)], were subjected to NaCl stress in greenhouse conditions. The 9-month-old plants were exposed to four different NaCl levels (0, 30, 60, or 90 mm) in sand culture for 3 months. Plant biomass (fresh weight, dry weight, root length, shoot length, and leaf thickness), physiological attributes [number of stomata, stomatal size, number of epidermal cells, photosynthesis rate, stomatal conductance (gS), water use efficiency, and transpiration rate]. and ion content (Na+, K+, Ca+2, Mg+2, and Cl–) were adversely affected by salt stress, but salt-tolerant cultivars were comparatively less affected. Salt stress also enhanced antioxidant enzyme activity (superoxide dismutase, catalase, and peroxidase), particularly in salt-tolerant cultivars. The salt-sensitive cultivars accumulated the greatest content of Na+ and Cl– in their leaves, whereas the salt-tolerant cultivars accumulated the greatest content of Na+ and Cl– in their roots, an adaptation to combat the highly saline conditions. Overall, it was concluded that the salt tolerance of rootstocks is associated with a greater antioxidant enzyme activity and differing accumulation patterns of Na+, K+, Cl–, Mg+2, and Ca+2 in leaves and roots; these can be considered potential indicators of a cultivar's sensitivity to salt stress.

International audienceCyclofructans (CF) are cyclic oligosaccharides consisting of a crown ether core with pendent fructofuranose units. These unique macrocycles were reported recently to be powerful chiral selectors. Derivatized and bonded to silica, CFs make excellent chiral selectors for HPLC. In this study, several new derivatives of cyclofructan 6 (CF6) were prepared by introducing aromatic moieties with electron-withdrawing chloro and nitro groups and an electron-donating methyl group. Their enantioselectivities were evaluated in the normal phase mode in comparison to the commercially available cyclofructan columns (LARIHC CF6-P, LARIHC CF6-RN, and LARIHC CF7-DMP). In several cases, the columns prepared in this work showed improved enantioselectivity over the existing commercially available stationary phases. Furthermore, an evaluation of the number and position of chloro and methyl groups on the phenyl substituents of CF6 is discussed in terms of their ability to alter enantioselectivity

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Seedlings recovered from underdeveloped seeds of different commercial cultivars of Citrus were studied for their ploidy level. Cytological examination revealed that maximum triploid plants were found in lime Kaghzi (15.5%) followed by grapefruit Foster, mandarin Kinnow, sweet orange Musambi and mandarin Feutrell's Early (7.3%). Lime also produced the highest percentage of tetraploids (9.1%) followed by mandarin Kinnow and grapefruit Foster, while the minimum was found in mandarin Feutrell's Early. The polyploids were transplanted in pots and after hardening they were grown in the greenhouse for further morphological and genetic assays. 125chlorobenzene for 2-3 h at 20-26°C. Then they were dipped in fixative (100% ethyl alcohol, glacial acetic acid and chloroform in 6:1:3) for 10-12 h at 4°C. After fixation samples were washed with sterilized water. For microscopic observation the material was hydrolyzed with 5M HCl at 25°C for 20 min. Samples were dipped in Mordant solution containing 4% FeNH 4 (SO 4 ) 2 12 H 2 O for 1 h and washed 4-5 times with sterilized water. Samples were stained with 0.5% hematoxylin dye for 2-4 h (Gmitter et al. 1990). Prepared squashes were observed under Nikon inverted microscope at 10× × 100× magnification. After cytological confirmation diploids were discarded. The polyploids were transplanted in pots filled with sterilized substrate containing sand, silt and farmyard manure (2:1:1). When seedlings obtained 10-15 cm height, they were planted in the greenhouse. The experiment was laid out in Completely Randomized Design (CRD). Every cultivar included 3 randomized plots. Data were analyzed statistically with Duncan's Multiple Range Test (Steel, Torrie 1980). RESULTS AND DISCUSSION Seed size and germination percentageCitrus cultivars were examined for seed size viz. developed and underdeveloped. Significantly higher numbers were found in grapefruit cv. Foster (10 seeds) for developed seeds and in mandarin cv. Kinnow (17 seeds) for underdeveloped seeds (Table 1). The results are strengthened because triploids were obtained from underdeveloped seeds ranging 1/3 to 1/6 of size of developed seeds yielding mostly diploids (Esen, Soost 1973a,b). 1 haploid, 18 diploids and 51 triploids were found in plants originating from 82 underdeveloped seeds out of 2,049 seeds from pummelo cultivar Banpeiyu crossed with grapefruit (Toolapong et al. 1996). Maximum germination percentage was found in Musambi (42.5%) followed by Kaghzi (35.5%), while minimum germination was observed in Feutrell's Early (25.0%), Foster (29.5%) and Kinnow (35.3%). Plant growth in Citrus cultivars Diploid seedlingsRegarding total plant growth, results were found highly significant for diploid seedlings. Maximum plant growth was observed in Foster grapefruit plants (12.38 cm), followed by Musambi sweet orange, Feutrell's Early mandarin and Kaghzi lime (10.02 cm). Seedlings of mandarin cv. Kinnow depicted the least growth (9.44 cm) of all investigated cultivars (Table 2). Diploids are reported to grow more rapidly (Khan...