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排序方式: 共有530条查询结果,搜索用时 15 毫秒
1.
Praveen C. Verma Debasis Chakrabarty Satya Narayan Jena Devesh K. Mishra Pradhyumna K. Singh Samir V. Sawant Rakesh Tuli 《Industrial Crops and Products》2009,29(2-3):581-589
Vanilla is a large genus of about 110 species in the orchid family (Orchidaceae), including the species Vanilla planifolia from which commercial vanilla flavoring is derived. Since most species of vanilla are considered rare and endangered there is an urgent need to conserve them through genetic analysis and propagation/conservation studies on this crop.The present study investigated the genetic diversity among nine leafy- and leaf-less Vanilla species employing 30 decamer RAPD primers and 10 ISSR primers. The species under study were diverse and displayed a range of variability (0–66% and 0–81% for RAPD and ISSR, respectively). A total of 154 RAPD polymorphic markers (83.24%, h = 0.378) and 93 ISSR polymorphic markers (86.11%, h = 0.363) were used to generate a genetic similarity matrix followed by the cluster analysis. Specific groupings were revealed by each cluster analysis with slight variation between two different markers. Among the nine species studied, V. planifolia, Vanilla aphylla and Vanilla tahitensis revealed very low level of variation within their collections, thus indicating a narrow genetic base. The large genetic distance of Vanilla andamanica from other species suggests its different origin. A close genetic affinity was observed between the pairs V. planifolia, V. tahitensis and Vanilla albida, V. aphylla. These are the first comparative results for RAPD and ISSR reporting inter-relationship among nine cultivated, wild and hybrid Vanilla species. 相似文献
2.
3.
Soil organic carbon stock variability in the Northern Gangetic Plains of India: interaction between agro‐ecological characteristics and cropping systems
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V. K. Singh M. Rani B. S. Dwivedi S. K. Singh V. K. Gupta K. Majumdar R. P. Mishra 《Soil Use and Management》2015,31(4):461-473
Soil organic carbon (SOC) content and its spatial distribution in the Northern Gangetic Plain (NGP) Zone of India were determined to establish the cause–effect relationship between agro‐ecological characteristics, prevailing crop management practices and SOC stock. Area Spread Index (ASI) approach was used to collect soil samples from the NGP areas supporting predominant cropping systems. Exponential ordinary kriging was found most suitable geo‐statistical model for developing SOC surface maps of the NGP. Predicted surface maps indicated that 43.7% area of NGP had 0.5–0.6% SOC, while the rest of the area was equally distributed with high (0.61–0.75%) and low (< 0.5%) SOC content levels. Averaged across cropping systems, maximum SOC content was recorded in Bhabar and Tarai Zone (BTZ), followed by Central Plain Zone (CPZ), Mid‐Western Plain Zone (MWPZ), Western Plain Zone (WPZ) and South‐Western Plain Zone (SWPZ) of the NGP. The SOC stock was above the optimum threshold (> 12.5 Mg/ha) in 97.8, 57.6 and 46.4% areas of BTZ, CPZ and MWPZ, respectively. Only 9.8 and 0.4% area of WPZ and SWPZ, respectively, had SOC stock above the threshold value. The variation in SOC stock was attributed largely to carbon addition through recycling of organic sources, cropping systems, tillage intensity, crop or residue cover and land‐use efficiency, nutrient‐use pattern, soil texture and prevailing ecosystem. Adoption of conservation agriculture, balanced use of nutrients, inclusion of legumes in cropping systems and agro‐forestry were suggested for enhancing SOC stock in the region. 相似文献
4.
Increasing atmospheric carbon dioxide concentration (CO2) is an important component of global climate change that will have a significant impact on the productivity of crop plants. In recent years, growth and yield of agricultural crop plants have been shown to increase with elevated CO2 (EC) and have enticed considerable interest due to variation in the response of crop plants. In this study, comparative response of two mung bean cultivars (HUM‐2 and HUM‐6) was evaluated against EC at different growth stages under near‐natural conditions for two consecutive years. The plants were grown in ambient as well as EC (700 ppm) in specially designed open‐top chambers. Under elevated CO2, marked down‐regulation of reactive oxygen species (ROS) levels, membrane disruption and activities of superoxide dismutase and catalase were noticed in both the cultivars, but the extent of reduction was more in HUM‐6. As compared to ambient CO2, EC increased total chlorophyll, photosynthetic rate, growth and yield parameters. Cultivar‐specific response was noticed as HUM‐6 showed higher increase in yield attributes than HUM‐2. Under CO2 treatment, soluble protein and reducing sugars decreased while total soluble sugars and starch showed an opposite trend. Principal component analysis showed that both the cultivars responded more or less similarly to EC in their respective groupings of physiological and growth parameters, but the magnitude of ROS and antioxidative enzymes was variable. The experimental findings depict that both the cultivars of mung bean showed contrasting response against EC and paved the way for selecting the suitable cultivar having higher productivity in a future high‐CO2 environment. 相似文献
5.
Identification of internal control genes in milk‐derived mammary epithelial cells during lactation cycle of Indian zebu cow
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6.
Root growth, water potential, and yield of irrigated rice 总被引:3,自引:0,他引:3
Root length density (Lv), leaf water potential (Ψ leaf) and yield of rice were studied in 1983 and 1984 on a Phool bagh clay loam (Typic Haplaquoll) and on a Beni silty clay
loam (Aquic Hapludoll) in the Tarai region of Uttar Pradesh under naturally fluctuating shallow (0.07–0.92 m) and medium-depth
(0.13–1.26 m) water table conditions with six water regimes ranging from continuous submergence under 0.05 m ± 0.02 m (Ic)
to completely rainfed (Io). In irrigation treatments, Ic1, Ic3, Ic5, and Ic7, 0.07 m irrigation was applied on days 1, 3,
5, and 7 respectively, after the disappearance of ponded water. Maximum rooting depth (0.55 m in the shallow and 0.65 m in
the medium-depth water table) was attained at the dough stage (125 days after transplanting) and was more strongly influenced
by fluctuations in water table depth than by the water regime. For wet regimes (Ic1–Ic5), roots were concentrated at and above
the water table interface and had greater horizontal development, whereas in dry regimes, (Ic7 and Io) they were concentrated
in lower horizons and had a more vertical distribution. Like Lv, Ψ leaf was not significantly affected by water regime up to 90–95 days after rice transplanting but was significantly affected
thereafter, except for Lv beneath 0.2 m–0.25 m. Grain yields with irrigation treatments Ic1 and Ic3 under shallow and Ic1
under medium-depth water table conditions were not significantly different from those under continuous submergence, but there
was a (nonsignificant) trend to lower yield with less water. However, differences among the wet regimes (Ic, Ic1, and Ic3)
were small (141–490 kg ha–1) under shallow and 413–727 kg ha–1 under medium-depth water table conditions. The results demonstrate that optimum yield (5500–6000 kg ha–1) could be obtained under Tarai conditions by adopting an intermittent irrigation schedule of 3–5 days after the disappearance
of ponded water under shallow, and of 1–3 days under medium-depth water table conditions, in place of continuous submergence.
Received: 26 February 1996 相似文献
7.
Sujata Mohapatra Rajesh Kumar Srianga Tilak Patnaik Choudhury Suryakant Mishra Lakshman Sahoo Jitendra Kumar Sundaray 《Aquaculture Research》2020,51(8):3230-3236
Monocrotophos (MCP) is one of the organophosphate pesticides extensively used in agriculture and animal husbandry. The present study reports the effects of sub‐lethal concentrations of MCP on gonadosomatic index (GSI), gonadal histology and breeding fitness of the fish Anabas testudineus. The fish were exposed to three sub‐lethal concentrations of monocrotophos (T1: 3.5 mg/L, T2: 5.3 mg/L and T3: 10.6 mg/L) for 45 days with 12 fish (males and females in equal numbers) in each tank, and one group was kept as control (C) without any treatment. GSI decreased in all treatment groups in comparison with control. Significant decrease in fertilization and hatching rate was observed at all concentrations in comparison with control on 15, 30 and 45 days of monocrotophos exposure. The decreased vitellogenesis, disruption of follicular wall and oocyte atresia were observed in all the treated females at 30 and 45 days of exposure. Rupture of seminiferous tubules was noticed in all the treated males irrespective of exposure periods. The results thus indicated that monocrotophos could deleteriously impact the gonadal structure and function in A. testudineus, which could seriously impact the reproductive success of the animal. 相似文献
8.
Swagatika Sahu Basanta Kumar Das Bibhudendu Kumar Mishra Jyotirmayee Pradhan Surya Kanta Samal Niranjan Sarangi 《Aquaculture Research》2008,39(16):1720-1730
The aim of this study was to evaluate the dietary dosages of turmeric that enhance immune response and disease resistance against the opportunistic pathogens Aeromonas hydrophila in Labeo rohita fingerlings. Hence, four different dosages of turmeric at 0.1, 0.5, 1.0 and 5.0 g kg?1 feed were given to the fingerlings of L. rohita for 60 days at 4% body weight. At every 20‐day interval, different biochemical, haematological, enzymatic and immunological parameters of fish were evaluated. After 60 days, fish were challenged with A. hydrophila. The mortality (%) was recorded on the tenth day post challenge. Most of the immune parameters including lysozyme activity, superoxide anion production and serum bactericidal activity were significantly (P<0.05) higher on 60 days of feeding of 1.0 g of turmeric per kg of feed. Challenge study indicated 100% and 89% survivability in the group of fish fed with 5.0 and 1.0 g of turmeric per kg of feed respectively. Feeding of turmeric might have maintained long‐term protection in fish by elevating the nonspecific immune system such as Nitroblue tetrazolium (NBT), lysozyme and serum bactericidal activity. The result showed that turmeric at a dose of 1.0 g kg?1 feed for 60 days provided the greatest protection to pathogen challenge. 相似文献
9.
Kai Wang Zhiqiang Zhu Huagang Huang Tingqiang Li Zhenli He Xiaoe Yang Ashok Alva 《Journal of Soils and Sediments》2012,12(4):556-564
Purpose
Soil contamination by multiple organic and inorganic contaminants is common but its remediation by hyperaccumulator plants is rarely reported. The growth of a cadmium (Cd) hyperaccumulator Sedum alfredii and removal of contaminants from Cd and polycyclic aromatic hydrocarbons (PAHs) co-contaminated soil were reported in this study. 相似文献10.
Lei Y Mulchandani P Chen W Mulchandani A 《Journal of agricultural and food chemistry》2005,53(3):524-527
A microbial biosensor for rapid, sensitive, selective, and cost-effective determination of the total content of organophosphorus nerve agents with p-nitrophenyl substituent is reported. The biosensor consisted of genetically engineered PNP-degrader Pseudomonas putida JS444 expressing organophosphorus hydrolase (OPH) on its cell surface immobilized on a dissolved oxygen electrode. Surface-expressed OPH catalyzed the hydrolysis of organophosphorus pesticides with p-nitrophenyl substituent such as paraoxon, methyl parathion, and parathion to release p-nitrophenol that was oxidized by the enzymatic machinery of Pseudomonas putida JS444 to carbon dioxide while consuming oxygen. The oxygen consumption was measured and correlated to the concentration of organophosphates. The sensor signal and response time were optimized with 0.086 mg dry weight of cell and operating in 50 mM pH 7.5 citrate-phosphate buffer with 50 microM CoCl(2) at room temperature. When operated at optimized conditions, the biosensor measured as low as 55 ppb of paraoxon, 53 ppb of methyl parathion, and 58 ppb of parathion without interference from most phenolic compounds and other commonly used pesticides, such as atrazine, coumaphos, sutan, sevin, and diazinon. The operational life of the microbial biosensor was approximately 5 days when stored in the operating buffer at 4 degrees C. 相似文献