M. M. Ajlouni

TOMATO ROOT AND SHOOT RESPONSES TO SALT STRESS UNDER DIFFERENT LEVELS OF PHOSPHORUS NUTRITION

Abstract Crops differ in their ability to grow under saline conditions and their responses are quite variable and not fully understood. This study was conducted to evaluate the root and shoot responses of tomato to salt stress conditions under different levels of phosphorus (P) nutrition. Tomato seedlings (cv Riogrande) were grown in 500 mL glass jars containing Hoaglands solutions which were salinized by four levels of NaCl salt (0,50,100, and 150 mM NaCl) and/or enriched with three P levels (0.5,1, and 2 mM P) making nine combination treatments. Plants were harvested at the vegetative growth stage and data were collected for root and shoot characteristics. The results indicate that increasing salinity stress was accompanied by significant reductions in shoot weight, plant height, number of leaves per plant, and a significant increase in leaf osmotic potential and peroxidase activity regardless of the level of P supplied. Both root length and root surface area per plant were decreased significantly unde...

Somatic embryogenesis in the endemic black iris.

Somatic embryogenesis was achieved from callus, cell suspension and protoplast culture systems in the endemic black iris (Iris nigricans). Subculture of friable callus fragments on embryogenesis induction medium (EIM) containing 4.5 μM 2,4-dichlorophenoxyacetic acid (2,4-D), 0.5 μM kinetin, 4.5 μM 1-naphthaleneacetic acid (NAA) and 300 mg l-1 proline in the dark was necessary before transfer to regeneration medium (RM). Regeneration was studied by transferring friable callus fragments from EIM to RM containing (0.0, 4.5, 9.0, 13.5 μM) of either 6-benzyladenine (BA), 2-isopentenyladenine (2iP), zeatin or thidiazuron (TDZ) in combination with 0.49 μM indole-3-butyric acid (IBA), 0.45 μM 2,4-D. Maximum embryogenesis was obtained at 4.5 μM BA while zeatin and TDZ were not effective and embryogenesis did not occur with these treatments. Sucrose at 0.2 M was more effective for embryogenesis when compared to glucose or fructose. Growing cells in suspension culture on EIM containing 4.5 μM 2,4-D in combination with 0.2 M sucrose for four weeks and transferring cells to RM (containing 4.5 μM BA) gave significant embryogenesis with maximum number of embryos (3568 embryos/g cells). Using 4.5 μM 2,4-D in protoplast culture was necessary for the best protoplast division and colony formation. In all experiments, embryos developed on RM were transferred to hormone-free medium (HFM) and 90% converted to rooted plantlets. Produced plantlets gave 95% survival ex vitro. Plantlets developed to whole plants in the greenhouse and flowered.

Micropropagation in wild pear (Pyrus syricca)

Abstract Some factors which affect the in vitro propagation of wild pear ( Pyrus syrica ) were studied. Successful shoot proliferation was obtained on Murashige and Skoog medium supplemented with 1.5–2.0 mg 1 −1 benzyl adenine. Shoot height decreased to 1.8–1.6 cm and 1.3 cm with benzyl adenine (1.5–2.0 mg 1 −1 ) and zeatin (1.0–2.0 mg 1 −1 ), respectively. Benzyl adenine (at 2.0 mg 1 −1 ) and zeatin (at 1.5–2.0 mg 1 −1 ) enhanced callus formation. Indole butyric acid, indole acetic acid and naphthalene acetic acid induced in vitro rooting and a maximum of 72% rooting was achieved at 3.0 mg 1 −1 indole acetic acid. Neither activated charcoal nor polyvinylpyrrolidone influenced in vitro rooting. Ex vitro rooting was unsuccessful when treating shoot microcuttings with 0.0, 5.0, 10.0, or 15.0 mg 1 −1 indole butyric acid, indole acetic acid, or naphthalene acetic acid for l h and grown under intermittent water mist. An average of 95% survival was achieved when rooted microshoots were acclimatized under glass or plastic covers using intermittent mist in the greenhouse.

Chemical composition variations of tissues and processing characteristics in ten potato cultivars grown in Jordan

Ten certified potato cultivears (Ajax, Crystal, Kennebec, Labelle, Liseta, Mondial, Norchip, Signa Gold, Spunta and Vital) were grown at Jordan University Experimental Station in 1993. At harvest, tuber subsamples of each plot were analyzed for physical properties and chemical composition. Processed chips and fries were evaluated for appearance, color, aroma, texture, taste and overall acceptability. There was significant variation in tuber weight which ranged from 108.8 (Kennebec) to 148.7 g (Labelle), specific gravity which varied from 1.022 (Mondial) to 1.191 g/ml (Spunta), total solids which ranged from 18.9 (Ajax) to 23.9% (Vial), and chemical composition. Cultivars Liseta, Signa Gold, Mondial, Kennebec and Crystal produced highly acceptable chips and fries, while Ajax, Kennebec, Norchip and Spunta produced excellent fries only. All other cultivars produced less acceptable chips and fries.CompendioDiez cultivares de papa certificados (Ajax, Crystal, Kennebec, Labelle, Liseta, Mondial, Norchip, Signa Gold, Spunta y Vital) fueron sembrados en la Estación Experimental de la Universidad de Jordania en 1993. A la cosecha, se analizaron las propiedades físicas y la composición química de submuestras de tubérculos de cada parcela. Las papas fritas y las hojuelas procesadas fueron evaluadas por apariencia, color, aroma, textura, sabor y sobre todo aceptabilidad. Hubo una variatión significativa en el peso de los tubérculos desde 108.8 (Kennebec) a 148.7 g (Labelle); la gravedad específica varié de 1.022 (Mondial) a 1.191 g/ml (Spunta); los sólidos totales variaron de 18.9 (Ajax) a 23.9% (Vital), y también hubo variatión en la compositión química. Los cultivares Liseta, Signa Gold, Mondial, Kennebec, Norchip y Spunta produjeron excelentes papas fritas y hojuelas muy aceptables, mientras que Ajax, Kennebec, Norchip y Spunta solo produjeron excelentes papas fritas. Todos los otros cultivares produjeron papas fritas y hojuelas menos aceptables.

Incorporating Land Use Mapping and Participation in Jordan

Abstract In this study, analysis of land use and suitability maps for 2 contrasting mountainous ecosystems was used to identify areas where a change from existing to potential land use was required. A socioeconomic survey was carried out to select locations for implementing 2 land management packages with the full participation of farmers. The first package included cultivation of wheat landraces in a high-rainfall site (Ajloun), while the second included community-based rangeland rehabilitation and management, including fodder shrub plantations in water harvesting structures in the low-rainfall rangeland areas (Jiza). Results showed that the average grain and straw yield of wheat landraces was significantly higher than that of the improved cultivars, which could lead to high and diverse farm income. In the low-rainfall site, fodder shrubs increased the overall land productivity and aided in improving the cover of native vegetation. After 2 years of protection, dry matter production (620 kg/ha) in the community-protected location was significantly higher than that at an experimental station (465 kg/ha). Findings from both packages indicated the possibility of improving the suitability of both mountainous areas for rainfed cultivation while conserving agrobiodiversity. Development of the arid areas as open ranges could be enhanced by the introduction of suitable cultivation practices (contour furrows in this study), with a view to improving productivity and rehabilitating the native vegetation.

Stability of chemical parameters of tissue culture medium (pH, osmolarity, electrical conductivity) as a function of time of growth

Abstract Changes in medium pH, osmolarity (OS), and electrical conductivity (EC) were studied as a function of time in Murashige and Skoog (MS) liquid proliferation and rooting medium. Microshoots of wild pear (Pyrus syriaca), bitter almond, and ‘Spunta’ potato were targeted. Results indicated an acidic drift in pH in the different species on both proliferation and rooting medium. The EC was increased significantly with time whereas solution OS was decreased. Different species caused different effects on EC or OS depending on growth medium. The decline in OS in the proliferation medium was higher when pear and almond were grown, while on rooting medium the decline was sharper with potato and almond. The EC of proliferation medium was increased more when almond was grown; while on the rooting medium all species had similar effects. Under these saline conditions, low nutrient elements availability, poor plant growth, and nutrient element imbalance are expected. This study illustrates that the change in the ...