首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
The objective of this study was to evaluate the effects of elemental sulphur （S） and farmyard manure on soil pH, EC and N, S, P concentrations of tomato grown in a calcareous sandy loam soil. For this purpose, a pot experiment was conducted in greenhouse conditions. Sulphur was applied at 0, 50, 100, 150, 200, 400 mg kg~ and farmyard manure at 0, 3 ton da^-1 to the soil. Three weeks after applications, tomato seedlings were planted and 8 weeks later, the plants were harvested to determine N, S, P concentrations and dry matter yield. Soil pH and EC were determined in the soil samples taken at 3 different periods. Effects of sulphur and farmyard manure applications were not significant on N, P concentrations and dry matter yield of tomato plant. S concentration of tomato plant was increased by sulphur alone. Soil pH was decreased and soil EC was increased in both 2^nd and 3^rd soil sampling period by the sulphur applications. As a result of farmyard manure application, soil pH decreased in the 2^nd soil sampling period but increased in the 3^rd soil sampling period. Also, soil EC was significantly increased in 1^st and 3^rd soil sampling period. Farmyard manure had no significant effect on S supply to tomato plant. The N：S ratio of tomato plant was decreased by sulphur alone. However, the sulphur with farmyard manure applications decreased N：S ratio in lesser extend compared to the S applications.  相似文献   

2.
This research aimed at the use of natural products to extend the shelf life of perishable vegetables. Studies were conducted on the preservative effects of four plant extracts--Xylopia aethiopica, Piper nigrum, Tetrapleura tetraptera and Carica papaya seeds on tomato and pepper. Tomato and pepper were dipped into four different concentrations of aqueous extracts of the four plants as well as water serving as control. The result of the study showed that aqueous extract of all plants extended the shelf life of tomato and pepper with increasing concentration of the extracts, except for Carica papaya seeds which produced significant elongation of 12.0 ±0.6 d and 14.0 ± 0.7 d on tomato and pepper, respectively, at the least concentration of 0.25 mg/mL. The results showed that these ethnomedicinal plants can serve as good and potent sources of natural preservatives which can be used to substitute existing synthetics used in the food industry.  相似文献   

3.
Cu2+、Cd2+胁迫对番茄幼苗生长及过氧化物酶活性的影响   总被引：3，自引：2，他引：1  
笔者以番茄2个种（402,205）为材料,研究不同浓度Cu^2＋、Cd^2＋对番茄幼苗生长及过氧化物酶活性的影响,以期为Cu^2＋、Cd^2＋对番茄的伤害机制提供理论依据。  相似文献   

4.
The growth situation and peroxidase (POD) of seedlings of two tomato cultivars were investigated under the stress of different concentrations of Cu2+ and Cd2+. The toxicity differences of Cu2+ and Cd2+ to tomato seedlings and the corresponding differences between two tomato cultivars were observed through the stress trial with the above two heavy metal ions. The results showed that low concentration of Cu2+ and Cd2+ could promote the growth and could enhance the POD activity of tomato seedlings,while high concentration Cu2+ and Cd2+ could inhibit seedling growth and POD activity of tomato seedlings. Cd2+ functioned more obviously than that of Cu2+,two tomato cultivars also presented difference in response to heavy metal stress.  相似文献   

5.
Effects of Cu2+ and Cd2+ Stress on Growth and POD Activity of Tomato Seedling   总被引：14，自引：0，他引：14  
The growth situation and peroxidase (POD) of seedlings of two tomato cuhivars were investigated under the stress of different concentrations of Cu2+ and Cd2+. The toxicity differences of Cu2+ and Cd2+ to tomato seedlings and the corresponding differences between two tomato cultivars were observed through the stress trial with the above two heavy metal ions. The results showed that low concentration of Cu2+ and Cd2+ could promote the growth and could enhance the POD activity of tomato seedlings, while high concentration Cu2+ and Cd2" could inhibit seedling growth and POD activity of tomato seed-lings. Cd2+ functioned more obviously than that of Cu2+, two tomato cultivars also presented difference in response to heavy metal stress.  相似文献   

6.
Citrus fruits are rich in carotenoids.In the carotenoid biosynthetic pathway,lycopene β-cyclase（LCYb,EC：1.14.-.-） is a key regulatory enzyme in the catalysis of lycopene to β-carotene,an important dietary precursor of vitamin A for human nutrition.Two closely related lycopene β-cyclase cDNAs,designated CsLCYb1 and CsLCYb2,were isolated from the pulp of orange fruits（Citrus sinensis）.The expression level of CsLCYb genes is lower in the flavedo and juice sacs of a lycopeneaccumulating genotype Cara Cara than that in common genotype Washington,and this might be correlated with lycopene accumulation in Cara Cara fruit.The CsLCYb1 efficiently converted lycopene into the bicyclic β-carotene in an Escherichia coli expression system,but the CsLCYb2 exhibited a lower enzyme activity and converted lycopene into the β-carotene and the monocyclic γ-carotene.In tomato transformation studies,expression of CsLCYb1 under the control of the cauliflower mosaic virus（CaMV） 35S constitutive promoter resulted in a virtually complete conversion of lycopene into β-carotene,and the ripe fruits displayed a bright orange colour.However,the CsLCYb2 transgenic tomato plants did not show an altered fruit colour during development and maturation.In fruits of the CsLCYb1 transgenic plants,most of the lycopene was converted into β-carotene with provitamin A levels reaching about 700 μg g-1DW.Unexpectedly,most transgenic tomatoes showed a reduction in total carotenoid accumulation,and this is consistent with the decrease in expression of endogenous carotenogenic genes in transgenic fruits.Collectively,these results suggested that the cloned CsLCYb1 and CsLCYb2 genes encoded two functional lycopene β-cyclases with different catalytic efficiency,and they may have potential for metabolite engineering toward altering pigmentation and enhancing nutritional value of food crops.  相似文献   

7.
Identification of lxodid tick species on livestock in two districts, viz., D.I. Khan and Lakki Marwat of Northern Pakistan were made during the period from March to November 2009 through animals＇ survey and questionnaire. The main tick species were Amblyomma （14.3%）, Boophilus microplus （l 8.5%） and Hyalomma anatolicum and H. dromedarii （67.2%）. Out of 3009 collected ticks, the highest number of female （88.7%） and the lowest of males （ l 1.3%） belong to Boophilus; the lowest number of female （92.4%） and the highest of males （77.5%） belong to Amblyomma. However, cows were more susceptible than buffaloes and camels ranked third to ticks infestation. Moreover, cows, buffalos, goats and sheep harbored mixed infestation （had more than one type of ticks）, however, camels and donkey harbored single infestation （had only one type of tick）. An emerging ethno-veterinary or traditional remedy is poultry keeping for ticks＇ elimination in Lakki Marwat. The results of this research will be helped in taking appropriate measures to reduce tick infestation and to improve management practices. Hence, it will help to increase farm productivity and farmers income.  相似文献   

8.
In Kenya almost all sugarcane grown is under rainfall conditions that are planted in different locations during both long and short rainy seasons. Effect of season, location, cultivar and spacing on yield and quality of sugarcane is not clearly understood. The research was conducted at Kibos and Mumias to determine if the yields and quality of three sugarcane cultivars were affected by season, location and row spacing. Cultivars CO 945, EAK 73-335 and KEN 83-737 were manually planted during June and September in 2011. The trial was laid out as split-split plot arranged in a randomized complete block design （RCBD） replicated three times. Data collected at harvest, 17 months after planting （MAP） including cane yields, cane yield components and cane quality. The results revealed that cane length differed significantly between June and September. Stalk population and cane yields were significantly more at Mumias compared to Kibos. Cultivar EAK 73-335 showed significantly more cane yield （t/ha） than KEN 83-737 and CO 945. Both row spacing 1.2 m and 1.5 m did not affect cane yields. Brix%, Sucrose% and Purity% differed significantly between cultivars. The relationship between cane yield and stalk population was positive and significant, which indicated stalk population is a strong determinant of cane yield. The results showed that cane yield was significantly affected by location and cane quality by cultivars. Therefore Mumias is a better zone for sugarcane cultivation for both June and September seasons compared to Kibos.  相似文献   

9.
Phytophthora root and crown rot was found on the fruit trees in Bulgaria for the first time in the period 1998-1999. Monitoring of the disease spread from 2000 to 2007 points out incidence between 2 and 14 per cent, in some orchards and nurseries in the Southern part of Bulgaria. The following Phytophthora species were identified based on morphological and cultural characteristics, and temperature requirements： Phytophthora cactorum, Phytophthora citrophthora, Phytophthora drechsleri, Phytophthora cryptogea, Phytophthora hybrid specie and Pythium. Prevailing specie was P. cactorum. P. cryptogea and P. cactorum were confirmed by application of molecular methods. Nutritional requirements of P. cactorum and P. citrophthora were studied. Most Nitrogen sources stimulated the mycelial growth of P. cactorum to a higher extend, and reduced the colony size ofP. citrophthora. Different Carbon sources were utilized well by P. cactorum, and only saccharose and maltose had a stimulating effect on the mycelial growth of P. citrophthora. MgSO4.7H20 was the preferred sulfur source for both fungi, as L-cysteine and L-methionine only for P. cactorum. Phytophthora infection leads to physiological changes in the.host plant tissues. The tendency traced out is： about disorders in the amino acid metabolism, increase in the total sugars and slight reduction of the cellulose content. The total nitrogen, phosphorus and potassium content are reduced and the calcium and magnesium are increased. Photosynthesis of inoculated plants was suppressed and transpiration was increased.  相似文献   

10.
It is predicted that the current atmospheric CO2 concentration will be doubled and global mean temperature will increase by 1.5-6＆#176;C by the end of this century. Although a number of studies have addressed the separate effects of CO2 and temperature on plant-insect interactions, few have concerned with their combined impacts. In the current study, a factorial experiment was carried out to examine the effect of a doubling CO2 concentration and a 3℃ temperature increase on a complete generation of the brown planthopper （Nilaparvata lugens） on rice （Oryza sativa）. Both elevated CO2 and temperature increased rice stem height and biomass of stem parts. Leaf chlorophyll content increased under elevated CO2, but only in ambient temperature treatment. Water content of stem parts was reduced under elevated temperature, but only when coupled with elevated CO2. Elevated CO2 alone increased biomass of root and elevated temperature alone enhanced leaf area and reduced ratio of root to stem parts. Brown planthopper （BPH） nymphal development was accelerated, and weight of and honeydew excretion by the F1 adults was reduced under elevated temperature only. Longevity of brachypterous females was affected by a signiifcant interaction between CO2 and temperature. At elevated temperature, CO2 had no effect on female longevity, but at ambient temperature, the females lived shorter under elevated CO2. Female fecundity was higher at elevated than at ambient temperature and higher at elevated CO2 than at ambient CO2. These results indicate that the combined effects of elevated temperature and CO2 may enhance the brown planthopper population size.  相似文献   

11.
Spatial and structural characteristics of plant communities in the steppe ecosystems of the Baikal region, Russian Federation have been researched in connection with climate change and grazing. The present study, based on a total of 15 typical steppe sampling plots, investigated above-ground biomass （AGB）, below-ground biomass （BGB）, total biomass （TB） and root：shoot ratios （R：S） and their relationships with climatic factors and grazing. All biomass components varied widely depending on the climatic parameters and the degree of grazing affected transformation. A strong negative correlation between mean annual temperature （MAT） and total plant biomass was revealed for all study area. Mean annual precipitation （MAP） signiifcantly affected communities productivity increasing only in the south of the region. Due to the large and mountainous territory, the inlfuence of latitude and elevation （mountain） factors on the components of the biomass were studied. Although all studied plant steppe communities were transformed by uncontrolled grazing, their productivity is signiifcantly reduced only at plots with maximum digression. Vegetation shift is an indicator of climate change, as well as providing a diagnostic tool to build predictive models. Based on the complex index of effective precipitation, it was revealed that at the end of last century in the steppes of the Baikal region the structural and production processes will be affected by an arid climate trend.  相似文献   

12.
Essential oils （EOs） from Rosemary, Rosmarinus officinalis （Lamiaceae）, Orange, Citrus sinensis （Rutaceae）, Lavandula, Lavandula angustifolia （Lamiaceae）, False Yellowhead, Dittrichia viscosa （Asteraceae） and their major components were evaluated against root knot nematode, Meloidogyne incognita and Meloidogynejavanica. Second stage juveniles＇ （J2） paralysis and egg hatch inhibition were studied, while pulverized plant parts were tested for nematodes biological cycle arrest. All EOs paralyzed J2 and M. incognita were found more sensitive than M javanica with the EC50/4 days calculated at 250, 3,650 and 4,260 12g/mL for 1）. viscosa, L. angustifolia and R. officinalis, respectively. Similarly, all EOs inhibited nematodes egg hatch and D. viscosa exhibited the highest inhibition on egg hatch （100% inhibition at 5 μg/mL）. A significant influence of constituent terpenes （limonene, 1,8-cineole, linalool, camphor, L-borneol, caryophyllene oxide, β-eudesmol） dose and exposure time was indicated on egg hatch inhibition （56% to 100% at 500 μg/mL and 1,000 μg/mL）, while only β-eudesmol achieved paralysis of J2 and specifically against M. incognita （EC50/1d = 50μg/mL）. Interestingly, the most active botanical species arresting Meloidogyne spp. biological cycle in soil was C. sinensis （EC50 = 2 mg/g） and the most sensitive nematode species was M. javanica. The larvicidal and egg hatch inhibition activity holds promise towards the optimization of artificial terpene mixtures as novel and effective natural nematicides. Complex interactions of primary compounds and subsequent decomposition derivates compose efficacy profile of soil amendments.  相似文献   

13.
The effects of different tillage systems and poultry manure on soil physical properties, performance and nutrients in sorghum were studied for three years at Owo, southwest Nigeria. There was factorial combinations of herbicide-based zero tillage （ZT）, manual clearing （MC）, disc ploughing （P）, ploughing plus harrowing （P＋H） and ploughing plus double harrowing （P＋2H）, and two rates of poultry manure at 0 and 7.5 Mg ha^-1. Herbicide-based zero tillage and manual clearing reduced soil temperature and conserved more water than mechanized tillage techniques. Poultry manure reduced soil bulk density and temperature and increased soil water and porosity. There was a percentage decrease of leaf N, P, K, Ca and Mg concentrations, plant height, leaf area, stem girth, root dry weight, dry matter and grain yield in ascending order for herbicide-based zero tillage, manual clearing, ploughing, ploughing plus harrowing and ploughing plus double harrowing while percentage increases were recorded in a descending order for all the various combinations of tillage with poultry manure in that order. Poultry manure in combination with tillage increased dry matter and grain yield by 33.1 and 39.5%, respectively in comparison with tillage only. The manure-zero tillage methods increased dry matter and grain yield by 8% and 15%, respectively when compared with manure-mechanized tillage methods. Zero tillage or manual clearing in combination with 7.5 Mg ha^-1 poultry manure was most suitable for sorghum cultivation.  相似文献   

14.
Macroscopic grasp of agricultural carbon emissions status, spatial-temporal characteristics as well as driving factors are the basic premise in further research on China’s agricultural carbon emissions. Based on 23 kinds of major carbon emission sources including agricultural materials inputs, paddy ifeld, soil and livestock breeding, this paper ifrstly calculated agricultural carbon emissions from 1995 to 2010, as well as 31 provinces and cities in 2010 in China. We then made a decomposed analysis to the driving factors of carbon emissions with logarithmic mean Divisia index （LMDI） model. The results show：（1） The amount of agricultural carbon emissions is 291.1691 million t in 2010. Compared with 249.5239 million t in 1995, it increased by 16.69%, in which, agricultural materials inputs, paddy ifeld, soil, enteric fermentation, and manure management accounted for 33.59, 22.03, 7.46, 17.53 and 19.39%of total agricultural carbon emissions, respectively. Although the amount exist ups and downs, it shows an overall trend of cyclical rise; （2） There is an obvious difference among regions：the amount of agricultural carbon emissions from top ten zones account for 56.68%, while 9.84%from last 10 zones. The traditional agricultural provinces, especially the major crop production areas are the main source regions. Based on the differences of carbon emission rations, 31 provinces and cities are divided into ifve types, namely agricultural materials dominant type, paddy ifeld dominant type, enteric fermentation dominant type, composite factors dominant type and balanced type. The agricultural carbon emissions intensity in west of China is the highest, followed by the central region, and the east zone is the lowest; （3） Compared with 1995, efifciency, labor and structure factors cut down carbon emissions by 65.78, 27.51 and 3.19%, respectively;while economy factor increase carbon emissions by 113.16%.  相似文献   

15.
Dairy proteins included sweet whey solids （SWS）, whey protein concentrate （WPC）, milk protein concentrate （MPC） or sodium caseinate （SC） at level of 10% by weight were extruded with corn, rice, oat flour and other ingredients in a twin screw extruder. The functional properties and textural of crispy balls snacks （CBS） have been studied. The results showed that different protein types were significantly affected on functional and chemical properties of extrudate. The bulk density of CBS-SC was the lowest due to the highest expansion, while CBS-WPC retained the most water in the product, whereas, the maximum value of water solubility index was obtained in the CBS-CWP. Results also showed that protein digestibility value of extrudates had higher than non-extruded products. Color analysis of CBS-SC and CBS-SWS products had the highest AE values （P ≤ 0.05）, whereas CBS-SWS was statistically higher than CBS-SC in rank. Also, it was noticed that CBS-SWS had the highest value of browning index. The hardness of all extrudates products was desirable for expanded crispy where ranged from 17.3 N to 12.18 N. Generally, MPC and SC incorporated with cereal flour had acceptable quality characteristics and improved significantly the functional and texture properties of crispy balls products.  相似文献   

16.
Transgenic cotton was modified to express a gene derived from the bacterium Bacillus thuringiensis （Bt） to combat agriculturally important Lepidopteran pests. Elevated CO2 is expected to further alter the chemical composition of the plant, and this change may affect the role soil fauna plays in decomposition of Bt plants. A 3 months litterbag field study, consisting of four treatments using leaves from Bt cotton and near-isolines of non-Bt cotton grown under ambient and elevated CO2 levels, was conducted to investigate the abundance and community structure of soil Collembola that developed on the decaying leaf material. A total of 4,884 collembolans, including 13 genera of five families, were extracted in the present study. These results suggest that collembolan distribution was relatively uniform among the Bt cotton, elevated concentration of CO2 and control treatments, except for a significant difference in the densities of Onychiurus and Folsomides. No significant effects were detected in the decomposition rate between the two cotton varieties and two CO2 treatments. These findings indicated that transgenic Bt cotton plants and elevated CO2 do not have any adverse effect on the soil collembolans through the decomposition way in soil ecosystem.  相似文献   

17.
Biogas production generates digested slurry as a byproduct. It can be used as a fertilizer especially after its conversion into digested liquid. A pot based study was conducted in order to evaluate the effect of the application of digested liquid on CH4 and N2O flux, and plant biomass in paddy. Analysis revealed that digested liquid treated soils released more CH4 compared to ammonium sulphate and the control. Ammonium sulphate treated soil emitted the highest N20 whereas digested liquid application decreased its emission significantly. Further, the cumulative emission over 101 d of the experiment was found to be higher for CHa （16.9 to 29.9 g m^-2） compared to N20 （-49.3 to 18.9 mg m^-2） for all treatments. Digested liquid application had positive impact on plant variables such as panicle number and weight of panicles. This study suggests that digested liquid application significantly decrease N20 emission and increase CH4 emission possibly due to affecting the availability of organic C in the soil to microbial activity for methanogenesis. Another possibility for enhancing CH4 emission by following biogas digested liquid could be attributed to the increase in plant biomass.  相似文献   

18.
Influenced by animal welfare requirements and expensive labor cost, producers tend to feed layers in non-cage system such as floor rearing. With the development of commercial lines of dwarf layers, the property of dwarf layers＇ natural mating is drawing more and more attention. In this study, the authors hybridized Nongda Ill dwarf layers with White Leghorn chickens in floor-rearing system to research whether dwarf layers had defect in natural mating. Two steps of experiments were performed. The authors detected the fertilization rate of collected eggs, observed chickens＇ behavior in step I when a hen from other group was suddenly put into and recorded copulation number of every group in step II from 7：30 to 19：30. The results indicated that drawf cocks were as good as Leghorn cocks in natrual mating under floor-rearing system while drawf hens were better than Leghorn hens. Observation results showed no difference on reaction to intermixed hens between drawf layers and Leghorn layers. The best proportion of male to female for drawf layers was 1：8 in this experiment and dwarf cocks tended to mate dwarf hens rather than Leghorn hens.  相似文献   

19.
Transgenic corn was modified to combat lepidopteran pests, herbicide and other deteriorate environmental factors. However, fewer studies concerned the effects of transgenic corn cultivation on the soil Collembola in black soil region in China. In Jilin black soil region, a six treatments study including three corn varieties （transgenic corn, control and local variety） and two sampling locations （in rizhosphere and in between plants） were deployed to study the effect of transgenic corn cultivation and sampling location on densities, species richness and community structure of Collembola. We found that root biomass was marginally decreased in transgenic corn and control variety when compared to local variety. Collembola significantly affected by sampling location treatments. Densities and species richness of collembolans significantly decreased in ＂between plants＂ than in ＂rizhosphere＂. Densities of Collembola were impacted by corn varieties. In the whole growing season, densities of Collembola significantly decreased in control than in local variety. Collembolans in transgenic variety only slightly decreased in ＂jointing stage＂ than local variety. Collembolans adversely affected in ＂between plants＂ when compared to ＂in rhizosphere＂ in ＂seeding stage＂ but not other stages. These variations of collembolans were in lines with the trend of corn root biomass. It is indicated that Collembola variations could be caused by food resources （root biomass） but not corn varieties （transgenic, control and local）.  相似文献   

20.
This study was carried out at the Genetic Engineering Lab, College of Agriculture, University of Basrah. DNA was extracted from samples containing meat of commercial products in the Basrah markets. The products subjected to analysis using polymerase chain reaction （PCR） with species specific repeat （SSR） and polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） techniques based on the sequence of the mitochondrial DNA cytochrome b gene （mtDNA cyt b gene）. Then digestion with the Alu l restriction enzyme to establish a differential diagnosis detects and discriminates between meat species and adulteration in the products. SSR primers were applied, has been detected amplification of the encoded gene product, generated 221 bp in some imported minced and canned meat samples. The results show that SSR analysis produced a pattern that allowed a direct identification of horse and donkey meats in some imported minced and canned meat samples （Hana, Monde and Bavaria）. The amplified 359 bp gene of mtDNA cyt b gene from samples in different product was cut using Alu 1 restriction enzyme resulting in restriction fragment length polymorphism （RFLP）. Alu 1 was used to distinguish between the animals meat that belong to the family or one species. The digestion of the PCR product showed differences between products. Where the fragment length generated were 74, 76 and 189 bp. It belonged to horse meat. The fraud was detected in Hana, Monde and Bavaria products available in Basrah markets showing the presence of horse meat in these products that labeled as beef meats 100%. This revealed mtDNA cyt b gene as highly conserved and consequently a good molecular marker for diagnostic studies. Thus, this technique can be applied to food authentication for the identification of different species of animals in food products.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号