Evaluation of Trichoderma harzianum for controlling root rot caused by Phytophthora capsici in pepper plants

The ability of Trichoderma harzianum to control the rotting of pepper ( Capsicum annuum ) plant roots caused by Phytophthora capsici was studied. Interactions between the fungi were assessed in vitro on three culture media (V8c, Czapek and 2% water agar) and in vivo in plants grown in a substrate inoculated with P. capsici and T. harzianum . Studies on mutual antagonism in vitro showed that P. capsici was inhibited by T. harzianum ; however, the intensity of inhibition differed according to the medium used, being greatest on Czapek. Analysis of the fungal populations in the plant growth substrate showed that T. harzianum consistently reduced that of P. capsici over time. This reduction in the pathogen population was associated with a reduction in root rot of between 24 and 76%, although plant growth (dry weight) was still reduced by 21.2–24.7%, compared with the uninoculated control. In the absence of T. harzianum with the same pathogen inoculum levels, the reduction in dry weight was 59.8–68.6%, suggesting that T. harzianum reduced the damage.     

Allelopathic effects of Leucaena leucocephala leaf litter on some forest and agricultural crops grown in nursery

An experiment was conducted to assess the effect of leaf litter of Leucaena leucocephala on two forest crops Sada koroi (Albizia procera), Ipil ipil (L. leucocephala) and three agricultural crops Falen (Vigna unguiculata), Chickpea (Cicer arietinum) and Arhor (Cajanus cajan) in the nursery of the Institute of Forestry and Environmental Sciences, Chittagong University, Bangladesh, in a Randomized Block Design. Results suggested that leaf litters of L. leucocephala induced inhibitory effects on germination and growth of bioassay. It was also found that the effect depended on concentration of extract and litterfall, type of receptor species. Higher concentration of the materials had the higher effect and vice versa. Growth response of receptor crops varied with the variation of leaf litter application. The study revealed that application of low-dose leaf litter specially litter of 10 g·m⁻² had stimulating effect on shoot growth of C. arietinum, V. unguiculata and A. procera. While in all other cases significant inhibitory effect was observed and it was significantly increased with the increase of leaf litter application. However, the trend of inhibition was uneven with treatments. Root growth was found to be more affected than shoot growth.     

氮磷配施对玉米-大豆套作模式下种间作用、玉米产量及干物质积累与转运的影响

以盆栽和田间小区试验结合的方法,通过设置根系分隔与不分隔方式及不同供氮(0、120、180、240 kg/hm²,记为N₀、N₁₂₀、N₁₈₀、N₂₄₀)、供磷水平(0、35、70、105 kg/hm²,记为P₀、P₃₅、P₇₀、P₁₀₅),探究在玉米-大豆套作模式下氮磷配施对种间作用、玉米产量及干物质积累与转运的影响。结果表明,1)氮磷互作效应对带状套作系统的种间促进作用显著,配施可缓解玉米与大豆的种间竞争作用,提高套作系统土地当量比率、种间竞争力和营养竞争比率,促进玉米对氮、磷素的吸收,表现出显著的套作产量优势和资源利用优势(LER>1),且优势效应高于单施氮、磷肥。2)氮磷互作对玉米各生育期干物质积累量的影响呈峰形变化趋势,中氮中磷(N₁₈₀P₇₀)处理可显著降低花前干物质的积累量,增加成熟期干物质积累总量,促进花后干物质积累向籽粒转运,提高玉米收获指数。3)种间作用和氮磷互作可显著影响玉米产量,提高套作玉米有效穗和穗粒数,两种植模式中无论施肥与否,在套作条件下玉米的产量均高于净作,且在N₁₈₀P₇₀处理时玉米产量达到最大值,套作较净作增产幅度达1.65%~20.43%。本研究结果表明,套作模式下玉米氮磷配施以施氮180 kg/hm²、施磷70 kg/hm²时,种间促进作用显著,可改善其穗部性状,有利于成熟期干物质的积累和向籽粒的转运,最终获得较高的产量。     

含羞草叶子提取物对常见农作物种子萌发生长的抑制作用

观察了含羞草叶子提取物对孟加拉常见农作物种子萌发生长的抑制作用.实验在27-30℃的室温和24小时的光照条件下进行.结果表明：不同浓度的含羞草叶子提取物明显影响所选的植物种子根,茎和侧根的延长和生长.生物学测定表明：高浓度（50%-100%）的提取物有较强的抑制作用.而低浓度 （10%-25%） 的提取物的抑制作用较弱.研究还显示,提取物对植物根和侧根的抑制作用比对种子萌发和茎的生长抑制作用更显著.     

Effect of light on oxygen consumption and ammonia excretion in Haliotis discus discus, H. gigantea, H. madaka and their hybrids

Oxygen consumption and ammonia excretion rates of three abalone species, Haliotis discus discus, H. gigantea, H. madaka and their hybrids were measured at 20 °C by incubating for 3 h under dark and light (N = 9–13 for each species and hybrid). Animals were fasted before and during the experiment and measurements were made first under dark followed by light on the next day. The rates increased with the increase in body weight and were higher under light than dark. On average, H. discus discus had higher oxygen consumption (DD; dark = 0.039, light = 0.04 ml/g/h) than H. gigantea (G; D = 0.033, L = 0.036) and H. madaka (M; D = 0.034, L = 0.035); the hybrids had varied patterns with respect to their parental species [DD × M (D = 0.032, L = 0.038); M × DD (D = 0.03, L = 0.038); G × DD (D = 0.035, L = 0.04) and DD × G (D = 0.03, L = 0.034), mother first]. M (0.261, 0.298 μmol/g/h) had the highest ammonia excretion rate while G (0.162; 0.264) and DD (0.229; 0.232) had the lowest under dark and light, respectively. The hybrids had varied patterns in comparison with their parents (DD × M = 0.247, 0.32;M × DD= 0.177, 0.28; DD × G = 0.249, 0.364 and G × DD = 0.116, 0.155). The O/N ratios under both conditions in all species and hybrids indicated that they had carbohydrate dominated metabolism. Results demonstrated physiological variability among the species and hybrids indicating necessity of different strategies for their management and aquaculture.     

Cornstarch and tannin in phenol–formaldehyde resins for plywood production

The aim of this work is to demonstrate the performances of cornstarch–quebracho tannin-based resins designed as adhesive in the plywood production. In this way, the cornstarch and quebracho tannin was introduced in the classic adhesive formulation in order to supply a part of phenol–formaldehyde (PF). The physical properties (rheological characterization, thermogravimetric analysis and solid phase ¹³C NMR analysis) of the formulated resins were measured. In order to evaluate the mechanical performances of optimal cornstarch–quebracho tannin-based resins, plywood panels were produced and mechanical properties were investigated. These mechanical properties included tensile strength, wood failure and 3-point bending strength. The performance of these panels is comparable to those of plywood panels commercial PF made.The results showed that plywood panels bonded with cornstarch–quebracho tannin–PF resins (15:5:80, w/w/w) exhibited better mechanical properties than plywood panels commercial PF made. The introduction of small proportions of cornstarch and quebracho tannin in PF resins contributes to the improvement of the boiling water performance of these adhesives. The formaldehyde emission levels obtained from panels bonded with cornstarch–quebracho tannin–PF were lower to those obtained from panels bonded with control PF. Solid state CPMAS NMR spectra indicates that no reaction at all between PF resins and cornstarch and quebracho tannin. Even when reaction does evidently not occur, the addition of cornstarch and quebracho tannin improves markedly the water resistance of PF resins.     

Dyeing of modified acrylic fibers with curcumin and madder natural dyes

Hydrophobic fibers are highly crysta lline and non-polar polymers hence pose a big problem for dyers. Modified acrylic fiber containing different amounts of amidoxime groups as a function of the nitrogen content was obtained and dyed with curcumin and madder natural dyes. The dyeing parameters, such as dye concentration, dye bath pH, salt concentration, temperature, and time and the effect of alum and ferrous sulfate used as mordants were investigated. Compared with the dyeings obtained from modified acrylics, those of blank samples appeared less in color strength values. The color strength was proportional to the nitrogen content of the sample and the maximum value was obtained at pH 2 and pH 5 using madder and curcumin, respectively. The fixation of the dye molecules to the modified acrylic fibers was investigated to show mainly ionic and physical bonds. The washing, perspiration, and rubbing fastness properties for the dyed samples were enhanced by application of alum. The light fastness ratings were also improved using ferrous sulfate especially for the case of the samples dyed with madder.     

Hydrochemical processes and metal composition of Ain Umm-Sabah natural spring in Al-Hassa Oasis Eastern Province, Saudi Arabia

This study was carried out to determine the hydro-chemical processes and the metal concentration of spring water to evaluate its suitability for irrigation and other purposes. A total of 10 water samples were collected from Ain Umm Sabah at different times and from different locations from the spring basin. EC (dS m(-1)), pH, temperature, total cations (Na, Ca, Mg, K) and anions [Cl, CO3, HCO3, SO4, NO3, Fluoride (F)] were determined. Some trace and heavy metals (Al, As, Ba, B, Br, Mo, Ni, Si, Cd, Cu, V, Fe, I, Pb, Mn, Zn, Sr, Se, Sb, La and Se were determined. The Spring water is classified as C4S2 (high salinity with medium sodicity problem water). Chloride (Cl) and nitrate (NO3) concentrations were higher than the permissible limits according to World Health Organization Standards. The Ain Umm Sabah water is Na-Cl dominant water and can create soil sodicity problems and cause Na and Cl ion toxicity to plants if used for irrigation of sensitive crops. The spring water is under-saturated (negative SI) with respect to calcite, dolomite, gypsum, anhydrite, halite, fluorite and aragonite and oversaturated (positive SI) with respect to goethite, siderite and hematite minerals. The concentration of all the estimated trace metals was within the permissible limits for its use as drinking water and other purposes according to WHO. Since the spring water contains high concentration of NO3, hence can not be used for drinking purposes without prior treatment. The study findings suggest careful use and pumping of water from the spring. Further studies are required on regular basis to monitor the depletion in the spring water level and the temporal change in water salinity.     

Biodiversity in Indigenous Germplasm of <Emphasis Type="Italic">Pyrus </Emphasis>from Pakistan Based on Phenotypical and Morphological Traits

A comprehensive analysis of various horticulturally important morphological traits of sixty pear accessions located in five districts of Azad Jammu and Kashmir (Pakistan) was carried out. Several qualitative and quantitative traits were investigated in situ and after the harvesting of leaf and fruit samples. The rich diversity was observed for qualitative traits (i.?e. growth habit, blooming time, intensity of flowering, fruit setting, ripening time, productivity, and fruit shape and color) among pear accessions. As for the quantitative traits, significant variation was observed for leaf area (8.96–27.17 cm²), flowering duration (11–24 days), fruit weight (68.1–322.3 g), average fruit length (2.68–9.87 cm) and average fruit width (1.82–8.12 cm) between pear accessions. Based on qualitative and quantitative data, two dendograms were constructed by using cluster analysis which separated pear accessions into three distinct groups. The cluster analysis showed considerable differences between the accessions for qualitative and quantitative traits. Furthermore, a close association between accessions was noted inside the clusters for qualitative and quantitative traits. The results showed rich diversity and similarity between the pear accessions and needs further assessment at molecular level to elucidate their phylogenetic relationship.     

Physico-Chemical Profiling of Promising Sweet Orange Cultivars Grown Under Different Agro-Climatic Conditions of Pakistan

Sweet oranges are produced on large scale all over the world and demanded due to less number of seeds and are better juice quality. A study was carried out with the objective to characterize promising sweet orange cultivars for better quality fruits production under different agro-climatic conditions of Punjab (Pakistan). Fruits of three promising sweet orange (Citrus sinensis L. Osbeck) cultivars viz. ‘Blood Red’, ‘Musambi’ and were harvested from commercial citrus groves at five different locations. Starting from Multan, in the direction of increasing altitude, four more sites viz. Sahiwal, Faisalabad, Sargodha and Chakwal were selected after every 100–150?km distance. Fruits were evaluated in terms of different physical and biochemical characters. Results showed significant influence of climatic conditions on physico-chemical properties of the cultivars at all the locations. Fruits harvested from Multan and Sahiwal showed higher fruit weight, diameter and peel weight. More juicy fruits with higher vitamin C content were produced under mild temperature environmental conditions of Chakwal. Overall, ‘Musambi’ fruits had more total soluble solids and reducing and total sugars. ‘Musambi’ was found to be good source of bioactive compounds i.?e. vitamin C and total phenolic content, had the maximum antioxidant activity as compared to ‘Blood Red’ and ‘Succari’ and may be explored as potential cultivar in Sargodha and Chakwal.