Effect of Drought Conditions at Boiling Stage on Some Chemical Constituents of Cotton Plant

The investigation was carried out to study the effect of drought conditions at boiling stage on chloroplast pigments and anthocyanin, in leaves, carbohydrate, phenols and total amino nitrogen content in leaves and roots, oil and protein contents in bolls of different ages. Seeds of cv. Giza 75 cotton were sown during 1987 and 1988 seasons in pots of 30 cm in diameter containing 11 kg of soil; after complete germination, thinning was carried out leaving one plant per pot. Plants were subjected to water stress conditions at boiling stage till the sign of wilting, while the control plants were irrigated regularly at this stage without allowing the plants to reach wilting stage and kept in turgid state. The results obtained can be summarized as follows:
1. Drought conditions decreased reducing sugar, nonreducing sugar, total soluble sugar and total amino nitrogen in leaves, while the reverse was true in roots.
2. Drought conditions reduced total and polyphenols content in leaves while it had no effect on phenols compounds in roots.
3. Drought conditions had no significant effect on pigments except total carotenoid in 1987 season.
4. Oil content in seeds of different boll ages decreased as a result of drought in both seasons.
5. In general drought condition increased protein content in 1987 season while the reverse was true in 1988 season.
6. Leaves and roots of wilted plants had more inhibitors as compared to turgid plants.     

Prediction of the optimum veneer drying temperature for good bonding in plywood manufacturing by means of artificial neural network

Veneer drying is one of the most important stages in the manufacturing of veneer-based composites such as plywood and laminated veneer lumber. Due to the high drying costs, increased temperatures are being used commonly in plywood industry to reduce the overall drying time and increase capacity. However, high drying temperatures can alter some physical, mechanical and chemical characteristics of wood and cause some drying-related defects. In this study, it was attempted to predict the optimum drying temperature for beech and spruce veneers via artificial neural network modeling for optimum bonding. Therefore, bonding shear strength values of plywood panels manufactured from beech and spruce veneers dried at temperatures of 20, 110, 150 and 180 °C were obtained experimentally. Then, the intermediate bond strength values based on veneer drying temperatures were predicted by artificial neural network modeling, and the values not measured experimentally were evaluated. The optimum drying temperature values that yielded the highest bonding strength were obtained as 169 °C for urea formaldehyde and 125 °C for phenol formaldehyde adhesive in beech plywood panels, while 162 °C for urea formaldehyde and 151 °C for phenol formaldehyde in spruce plywood panels.     

Root uptake of lipophilic zinc-rhamnolipid complexes

This study investigated the formation and plant uptake of lipophilic metal-rhamnolipid complexes. Monorhamnosyl and dirhamnosyl rhamnolipids formed lipophilic complexes with copper (Cu), manganese (Mn), and zinc (Zn). Rhamnolipids significantly increased Zn absorption by Brassica napus var. Pinnacle roots in (65)Zn-spiked ice-cold solutions, compared with ZnSO4 alone. Therefore, rhamnolipid appeared to facilitate Zn absorption via a nonmetabolically mediated pathway. Synchrotron XRF and XAS showed that Zn was present in roots as Zn-phytate-like compounds when roots were treated with Zn-free solutions, ZnSO4, or Zn-EDTA. With rhamnolipid application, Zn was predominantly found in roots as the Zn-rhamnolipid complex. When applied to a calcareous soil, rhamnolipids increased dry matter production and Zn concentrations in durum (Triticum durum L. cv. Balcali-2000) and bread wheat (Triticum aestivum L. cv. BDME-10) shoots. Rhamnolipids either increased total plant uptake of Zn from the soil or increased Zn translocation by reducing the prevalence of insoluble Zn-phytate-like compounds in roots.     

Socio-economic factors influencing marketing of non-timber forest products in tropical lowland rainforests of south-western Nigeria§

A number of factors persist to constrain the non-timber forest products (NTFPs) market and, by extension, its potential to contribute meaningfully to livelihood development and poverty reduction objectives. To better utilise the potential of NTFPs, it is important to have a better understanding of the key factors governing the success and failure of NTFPs trade. This paper reports on the market constraints and socio-economic factors that influence trade in five top-priority NTFPs within the tropical lowland rainforests of south-west Nigeria. The NTFPs investigated were bush mango (Irvingia gabonensis), African walnut (Plukenetia conophora), chew-stick (Massularia acuminata), fever bark (Annickia chlorantha) and bush pepper (Piper guineense). Field data were collected in 10 villages located within and around Omo and Shasha forest reserves using a household questionnaire survey. The results showed that seasonality, poor transport, lack of storage facilities and market information were the four main constraints influencing marketing and trade in the NTFPs. In addition, the level of education, gender (sex), household income, ethnicity, distance to the market and access to roads significantly influenced market knowledge and information among households involved in the trade of NTFPs. There is need to improve on the limited source of NTFPs information, enhance skills for product transformation, build innovative storage facilities, and develop the process of domestication and integration in traditional land-use systems.     

Effect of Boll Age and Harvesting Period on Fiber Properties of Egyptian and Upland Cotton Cultivars

The physical properties of cotton fibers for the successive age of development were studied in three different periods. Three cultivars of Egyptian and Upland cottons; Giza 75, McNair 220 and Tamcot H. 37 , were planted at Fayoum Experiment Farm, Faculty of Agriculture in 1984 season. Fiber properties were studied on samples obtained from five successive stages of boll development in three different periods. Data obtained revealed that fibers from both Egyptian and Upland cultivars showed substantial increment in micronaire reading up to 42 days after flowering. Micronaire reading showed a trend similar to fiber maturity percentage in studied cultivars.
Within each period, fibers tended to be stronger, more extensible, tougher and have higher stiffness with the increase in boll age. The rate of increment in the successive boll ages for fiber strength and elongation characters were markedly higher in the Egyptian cultivar than the American upland cultivars, especially in the younger boll ages. Fiber length was slightly affected by the environment growth conditions. However, the increase in fiber length was progressive from the age of 21 days up to the age of 35 days.     

Growth regulator and low-volume irrigation effects on grapefruit quality and fruit-drop

‘Marsh’ (Citrus paradisi Macf.) grapefruit trees on rough lemon (C. jambhiri Lush.) rootstock received irrigated and unirrigated treatments. Half of each irrigation treatment received a GA₃ + 2,4-D spray at color break. Pre-harvest sprays of GA₃ and 2,4-D extended the grapefruit harvest season by increasing fruit removal and rind puncture force, delaying development of mature color and decreasing late-season and post-freeze fruit-drop. Although soil moisture content in the top 0.9 m of unirrigated blocks was reduced by approximately 40%, xylem pressure potentials of these trees and performance of GA₃ + 2,4-D were unaffected. Soil moisture content was not an accurate indicator of tree water status for large grapefruit trees.     

Effectiveness of arbuscular mycorrhizal fungi in the protection of date palm (Phoenix dactylifera L.) against bayoud disease

In the present study, arbuscular mycorrhizal fungi (AMF) (Glomus monosporus, Glomus deserticola, Glomus clarum and a complex of native AMF coming from the Aoufous date palm grove in the south of Morocco) have been shown to protect date palm seedlings against bayoud disease. Treatment with AMF reduced disease severity by 8–77% depending on the AMF isolate used. In addition, all mycorrhizal fungi stimulate significantly shoot height and biomass and increase the number of leaves per plant. The plants associated with Aoufous complex present the best improvement of plant growth and great effectiveness in reducing bayoud disease incidence. Moreover, the AMF induce change in activities of two defence-related enzymes (peroxidases and polyphenoloxidases). The potential involvement of this induced biochemical defence reaction in protecting date palm against bayoud is discussed.     

Removal and Preconcentration of Cobalt Ions from Aqueous Media Using ImHA Packed Column by On-Line SPE System

This work assesses the use of immobilized humic acid (ImHA) onto aminopropyl silica (APS) as a sorbent for the removal and preconcentration of trace amounts of cobalt ions by on-line solid phase extraction (SPE) technique in the column system prepared in our laboratory. Different parameters, such as the effect of the pH, concentration, and flow rate, were studied and throughput was observed by a UV detector. All SPE steps were monitored by breakthrough curves used to visualize distribution of cobalt concentration between mobile and solid phase. The solutions collected from stripping steps were analyzed in atomic absorption spectrometer (AAS) and the amount of sorbed ions was calculated. Sorption characteristics were evaluated by using common adsorption isotherms and Scatchard plot analysis. From the obtained results, it was seen that sorption mechanism of cobalt ions were fitted to Langmuir model on a large scale and thought to be localized. Mean free energy (E?=?40.82?kJ?mol^?1) calculated from D-R isotherm showed that chemical interactions are more effective than physical interactions. This investigation reveals a new, simple, environmentally friendly, and cost-effective method for removal and preconcentration of cobalt ions from aqueous solutions by a new aminopropyl silica-immobilized humic acid material.