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1.
长枝木霉TICC鉴定及其生物学特性研究   总被引:2,自引:0,他引:2  
从土壤中分离得到1株木霉T1CC,为明确其分类地位及其生物学特性,对该菌进行形态学鉴定和分子鉴定,并对其生长培养基、光照、温度、碳源、氮源、微量元素和pH等生物学特性进行研究.鉴定结果显示,该菌株为长枝木霉(Trichoderm longibrachiatum).生物学特性结果表明:菌株T1CC在PDA上生长量最大,查氏培养基和基本培养基上生长量最小;不同光照条件下,菌丝生长无明显差异,但在连续光照条件下可明显促进孢子产生;在15~40℃范围能够生长产孢,在35℃时菌丝生长最快,但产孢量在25~35℃最大;果糖最能促进菌丝生长,果糖、可溶性淀粉最有利于产孢;谷氨酸对菌丝生长和孢子产生都有促进作用;Cu最能促进菌丝生长,而zn、K和Mg则对菌丝生长有一定抑制作用,Cu最有利于产孢,zn对产孢明显抑制;在pH/值在2~10范围内均可生长,在pH为5时为生长最佳,在pH值3~7范围内最有利于产孢.  相似文献   
2.
Snakehead fish (Channa striata) skin is a fishery by-product that has the potential for further processing because it contains a high amount of organic matter. This study investigates the effect of body weight on the chemical composition and collagen content of snakehead fish skin. This study used fresh snakehead fish of either gender. Their body weights were divided into three groups: small, medium, and large size. The characteristics of snakehead fish skin included proximate composition, amino acid content, collagen content, microstructure, and minerals. Snakehead fish skin from fish of different body weights indicated that the moisture content and ash tended to decrease, the protein content was relatively stable, and the lipid content tended to increase with increasing body weight. Glycine and proline comprised the highest percentages of amino acids at all levels of body weight, and the presence of hydroxyproline showed that snakehead fish skin was the source of collagen. There was no significant difference in body weight observed on collagen protein content of the skin. This study on the microstructure and mineral content of snakehead fish skin can be used as supporting information to promote the potential utility and economic value of the skin.  相似文献   
3.
Parasitoids are characterized by a defined range of hosts, either more specialist or generalist. Under natural conditions, females may encounter different host species on the same plant or in the same location. In this case, their preference for one host could influence their choice. However, the presence of less suitable hosts may also affect their choice and, in some cases, may reduce their interest in a patch where both preferred and less preferred hosts are available. The aim of the present study was to test the consequences of the simultaneous presence of three cereal aphids (Sitobion avenae Fabricius, Metopolophium dirhodum Walker, and Rhopalosiphum padi Linnaeus) on the parasitism by two of their parasitoids, Aphidius ervi Haliday and Praon volucre Haliday. Firstly, in the no-choice experiment, A. ervi parasitized on S. avenae at a significantly higher rate as compared to M. dirhodum, whereas no parasitism on R. padi was observed. P. volucre parasitized the three species of cereal aphids with a significant preference for S. avenae. Interestingly, when two or three host species were offered simultaneously in the same quantity to pairs of parasitoids, the level of parasitism was less than that observed for one host species alone. This observation exhibits a distractive effect on non-host species, from the defense mechanism of a non-suitable host or from the perception of bad quality patches. These results raise the question of the practical application of inundative release of parasitoids for biocontrol when several hosts are available simultaneously.  相似文献   
4.
Artificial neural network (ANN) analysis of immobilized Candida antarctica lipase B-catalyzed esterification of palmitic acid with xylitol was carried out. Temperature, time, amount of enzyme, amount of molecular sieve, substrate molar ratio and volume of solvent were the six important parameters used as the inputs of the network trained by Levenberg-Marquardt (LM) algorithm. After evaluating different ANN configurations, the best network was found to be consisted of two hidden layers with six and seven neurons in the first and second layers respectively, using a hyperbolic tangent sigmoid transfer function. The coefficient of determination (R2) and mean square error (MSE) values between the actual and predicted responses were 1 and 1.5025e−24 for the training and 0.97239 and 0.03259 for the testing datasets. The results indicate the good generalization performance of the neural network model and its capability to predict the conversion of the substrates.  相似文献   
5.
Seed coat development in the natural tetraploid Trifolium pratense L. was studied by electron microscopy. The mature seed coat derived from the outer integument is composed of three layers of cells. The cells of the outer epidermis divide anticlinally and undergo radial elongation to form a macrosclereid layer. The cells are characterized by thin walls, the presence of amyloplasts, and numerous vacuoles which are completely or incompletely filled with tannin. The outer tangential walls are thickened at an early stage. An electron-translucent cap develops in the outer tangential walls of the macrosclereid cells at the globular embryo stage. Osteosclereid cells are highly vacuolate with densely staining cytoplasm. Gradually, extensive intercellular spaces are formed. The parenchyma cells are small and have prominent intercellular air spaces. Maturation eventually leads to the disappearance of cytoplasm in all cells, and the compression of the cells of the parenchyma layer.  相似文献   
6.
This article describes the development of environmentally friendly nano-emulsion system for water-soluble herbicide application. Pseudoternary phase diagrams were established in the emulsion system of fatty acid methyl esters (FAMEs)/alkylpolyglucosides (APG) and/or 3-(3-hydroxypropyl)-heptamethyltrisiloxane (organosilicone)/water encompassed with 41% (w/w) glyphosate isopropylamine (IPA) as herbicide active. Pre-formulations were selected from isotropic (L) region in the phase diagrams and their emulsion system characteristics were determined. The microemulsion systems were chosen and then dispersed into water using low-energy stirring method (200 rpm for 5 min). Oil-in-water (O/W) nano-emulsions were formed with particle sizes of diameter less than 200 nm. The nano-emulsion systems showed significantly lower surface tension than a commercial formulation (Roundup®). In the biological application study, treatments of nano-emulsion formulations and Roundup® were applied on narrow-leaved weed Eleusine indica. Multiple doses of glyphosate IPA of the treatments were applied for the construction of dose-response curves for determination of effective dose (ED50). The nano-emulsion formulation showed lower ED50 was 0.40 kg a.e./ha in controlling the weed than Roundup® was 0.48 kg a.e./ha. This finding suggested that the possibility of using nano-emulsion system to increase penetration and uptake of glyphosate IPA.  相似文献   
7.
Effect of pressing time on physical and mechanical properties of phenolic-impregnated bamboo strips was evaluated. Bamboo strips (Gigantochloa scortechinii) were impregnated with low molecular weight phenol formaldehyde (LMwPF) resin. Samples were submerged in LMwPF resin using a vacuum chamber of 750 mmHg for 1 h before it was released within 1.5 h. Treated strips were dried in an oven with a temperature of 60 °C within 6–9 h. It was hot pressed at 14 kg m?2 and a temperature of 140 °C for 5, 8, 11, 14 and 17 min. The physical and mechanical properties of the test indicated that the properties of phenolic-treated strips have significantly increased as compared to control samples. Dimensional stability (water absorption, thickness swelling and linear expansion) of the phenolic-treated properties were significantly lower than control after 5-min pressing time. The antishrink efficiency (ASE) of phenolic-treated strips increased when pressing time were extended from 5 to 17 min. The mean value of modulus of rupture (MOR) for the control samples (177 N mm?2) showed a significant difference with phenolic-treated strips after 17-min pressing time (224 N mm?2). However, there is no significant difference in compression parallel to grain. The MOE of phenolic-treated strips was 21,777 N mm?2 and for control was 18,249 N mm?2, whereas the compression parallel to grain values for phenolic-treated and control samples were 94 and at 77 N mm?2, respectively.  相似文献   
8.
Abstract– The female reproductive traits of a small, North American catfish were studied over a two-year period in a population at the southern extreme of the species'range. The reproductive season was long for Noturus , possibly from February to September. Females matured at age 1 and probably reproduced in only a single year. Clutch sizes were 16–68 oocytes in females 33–47 mm SL, and only one lifetime clutch may be produced. Clutch size, dry mass and volume were related to female size, but ripening oocyte size was not. Clutch mass averaged 23% of total body mass just prior to spawning. Compared to a northern population, females had greater SL-adjusted body masses, clutch sizes and clutch volumes but smaller oocytes. Oocyte size accounted for 73% of the difference in clutch sizes and clutch volume 14%. Concerns about the comparability of present data for Noturus are expressed. The need to include many life-history traits, from several populations of each species, using standardized methods in analysis of functional responses is discussed.  相似文献   
9.
Amino acid surfactants are high-value surfactants which have excellent emulsifying characteristics and minimal toxicity to the living body. Enzymatic synthesis of palm kernel amino acid surfactant was optimized by response surface methodology (RSM) using palm kernel olein (PKO) and l(+)-lysine catalyzed by Lipozyme RM IM. The reaction was performed in batch mode stirred tank reactor (STR) with one multi-bladed impeller. A central composite rotatable design (CCRD) was employed to evaluate the interactive effects of various parameters. The parameters were temperature (A): (40.00–70.00 °C), impeller speed (B): (100.00–400.00 rpm), substrates ratio (C): (1.00–4.00 mmol) and enzyme amount (D): (5.00–8.00 g). The optimum condition derived via RSM at fixed reaction time of 24 h was temperature; 47.50 °C, impeller speed; 323.96 rpm, substrates ratio; 3.25 mmol and enzyme amount; 7.25 g. The experimental yield was 89.03% under the optimum condition, which compared well with the maximum predicted value of 93.77%.  相似文献   
10.
The management of weeds in Malaysian rice fields is very much herbicide‐based. The heavy reliance on herbicide for weed control by many rice‐growers arguably eventually has led to the development and evolution of herbicide‐resistant biotypes in Malaysian rice fields over the years. The continuous use of synthetic auxin (phenoxy group) herbicides and acetohydroxyacid synthase‐inhibiting herbicides to control rice weeds was consequential in leading to the emergence and prevalence of resistant weed biotypes. This review discusses the history and confirmed cases and incidence of herbicide‐resistant weeds in Malaysian rice fields. It also reviews the Clearfield Production System and its impact on the evolution of herbicide resistance among rice weed species and biotypes. This review also emphasizes the strategies and management options for herbicide‐resistant rice field weeds within the framework of herbicide‐based integrated weed management. These include the use of optimum tillage practices, certified clean seeds, increased crop competition through high seeding rates, crop rotation, the application of multiple modes of action of herbicides in annual rotations, tank mixtures and sequential applications to enable a broad spectrum of weed control, increase the selective control of noxious weed species in a field and help to delay the resistance evolution by reducing the selection pressure that is forced on those weed populations by a specific herbicidal mode of action.  相似文献   
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