Suicidal germination for parasitic weed control          下载免费PDF全文

Binne Zwanenburg  Alinanuswe S Mwakaboko  Chinnaswamy Kannan 《Pest management science》2016,72(11):2016-2025

Parasitic weeds of the genera Striga and Orobanche spp. cause severe yield losses in agriculture, especially in developing countries and the Mediterranean. Seeds of these weeds germinate by a chemical signal exuded by the roots of host plants. The radicle thus produced attaches to the root of the host plant, which can then supply nutrients to the parasite. There is an urgent need to control these weeds to ensure better agricultural production. The naturally occurring chemical signals are strigolactones (SLs), e.g. strigol and orobanchol. One option to control these weeds involves the use of SLs as suicidal germination agents, where germination takes place in the absence of a host. Owing to the lack of nutrients, the germinated seeds will die. The structure of natural SLs is too complex to allow multigram synthesis. Therefore, SL analogues are developed for this purpose. Examples are GR24 and Nijmegen‐1. In this paper, the SL analogues Nijmegen‐1 and Nijmegen‐1 Me were applied in the field as suicidal germination agents. Both SL analogues were formulated using an appropriate EC‐approved emulsifier (polyoxyethylene sorbitol hexaoleate) and applied to tobacco (Nicotiana tabacum L.) fields infested by Orobanche ramosa L. (hemp broomrape), following a strict protocol. Four out of 12 trials showed a reduction in broomrape of ≥95%, two trials were negative, two showed a moderate result, one was unclear and in three cases there was no Orobanche problem in the year of the trials. The trial plots were ca 2000 m²; half of that area was treated with stimulant emulsion, the other half was not treated. The optimal amount of stimulant was 6.25 g ha^?1. A preconditioning prior to the treatment was a prerequisite for a successful trial. In conclusion, the suicidal germination approach to reducing O. ramosa in tobacco fields using formulated SL analogues was successful. Two other options for weed control are discussed: deactivation of stimulants prior to action and biocontrol by Fusarium oxysporum. © 2016 Society of Chemical Industry  相似文献   

Effect of biochar amendment on soil physical,chemical and biological properties and groundnut yield in rainfed Alfisol of semi-arid tropics     

Kannan Pandian  Ponmani Subramaniayan  Prabukumar Gnasekaran  Swaminathan Chitraputhirapillai 《Archives of Agronomy and Soil Science》2016,62(9):1293-1310

The aim of this study was to evaluate the effect of biochar and organic soil amendments on soil physicochemical and microbial load, carbon sequestration potential, nutrient uptake and yield of groundnut in acidic red soil under rainfed condition. Biochar was prepared from red gram, cotton, maize stalk and mesquite wood using pilot scale slow pyrolysis biochar unit. The above sources of biochar at the rate of 2.5 and 5 t ha^?1 and enriched farmyard manure 0.75 t ha^?1, composted coir pith 10 t ha^?1 and arbuscular mycorrhizae 100 kg ha^?1 were applied as basal with required nitrogen, phosphorous and potassium fertilizer. Biochar amendment at the rate of 5 t ha^?1 reduced the bulk density from 1.41 to 1.36 g cm^?3 and increased the soil moisture 2.5%. With respect to soil chemical changes, it raised soil pH from 5.7 to 6.3; increased the cation exchange capacity 1.4 cmol⁺ kg^?1 and enhanced the carbon buildup 4.4 t ha^?1. The significant differences in bacteria, fungi and actinomycetes population were observed between biochar and control. The nitrogen, phosphorous and potassium were better utilized under biochar and composted coir pith, which was 21, 5 and 20 kg ha^?1 higher than control. The experimental results suggested that application of biochar to acidic red soil favoured good soil physical, chemical and biological environment, and these positive changes influenced growth and yield attributes and enhanced pod yield 29% over control.  相似文献   

Antifungal activity of silver nanoparticles synthesized using turnip leaf extract (Brassica rapa L.) against wood rotting pathogens     

Kannan Badri Narayanan  Hyun Ho Park 《European journal of plant pathology / European Foundation for Plant Pathology》2014,140(2):185-192

The synthesis of metal nanoparticles using greener methodology and its application in biological fields is a burgeoning field of research. We demonstrated the synthesis of silver nanoparticles using turnip leaf extract and its interaction with wood-degrading fungal pathogens such as Gloeophyllum abietinum, G. trabeum, Chaetomium globosum, and Phanerochaete sordida. TEM images revealed that the silver nanoparticles were predominantly spherical and loosely agglomerated with an average size of 16.14 nm. DLS measurement of silver nanoparticles revealed an average hydrodynamic diameter of ca. 39.5 nm with a zeta potential of ?14.8 mV at pH 7.5. FTIR spectra revealed the presence of amine and aliphatic esters, which were involved in the reduction and stabilization of silver nanoparticles. The as-synthesized silver nanoparticles showed broad spectrum antifungal activity against wood-degrading fungi by inhibiting growth. Thus, the greener-synthesized silver nanoparticles can be used as an antifungal agent against wood-degrading fungal pathogens.  相似文献   

Investigation on pre-zygotic barriers in the interspecific crosses involving Gossypium barbadense and four diploid wild species     

Sundaram Ganesh Ram  V. Thiruvengadam  S. Hari Ramakrishnan  J. R. Kannan Bapu 《Euphytica》2008,159(1-2):241-248

Interspecific hybridisation has played significant role in the improvement of economically useful traits such as productivity, earliness, fibre quality and resistance to pests and diseases in cotton. However, wide crosses are often limited by the operation of either pre or/and post-fertilization barriers. The present study on pollen tube behaviour of four diploid wild species viz., G. triphyllum, G. davidsonii, G. thurberi and G. armourianum in the pistils of G. barbadense was taken up to determine the extent of pre-zygotic barriers operating in these crosses. High rate of pollen germination (∼80%) and normal growth of pollen tubes were observed upon selfing of both G. barbadense and four wild species. Pollen tubes reached the pistils and fertilization was accomplished within 8 HAP in all the five parental species. In the interspecific crosses, pollen germination was normal in the cross involving G. armourianum and drastically inhibited in the crosses involving G. triphyllum, G. davidsonii and G. thurberi. Even though delayed pollen tube growth was a general feature in all the four crosses, successful fertilization was observed only in the cross involving G. armourianum. In crosses involving G. triphyllum, G. davidsonii and G. thurberi, pollen tubes failed to reach the ovary even at 24 HAP due to the presence of strong stylar and ovarian incompatibility. Abnormalities in pollen tubes such as swelling, twisting, intense callose plug formation, breakage, branching and reverse orientation were frequently observed among the incompatible crosses.  相似文献   

Prefertilization barriers to interspecific hybridization involving Gossypium hirsutum and four diploid wild species     

S. Ganesh Ram    S. Hari Ramakrishnan    V. Thiruvengadam    J. R. Kannan Bapu 《Plant Breeding》2008,127(3):295-300

Interspecific hybridization among species of cotton has lead to improvement in productivity, earliness, fibre quality and resistance to pests and diseases. However, wide crosses is often limited by the operation of either pre‐ or/and post‐fertilization barriers. An investigation on pollen tube behaviour of four wild species in the pistils of Gossypium hirsutum was taken up. Pollen germination was normal in crosses involving Gossypium triphyllum and Gossypium armourianum and markedly inhibited in the crosses involving Gossypium davidsonii and Gossypium thurberi. Pollen tubes reached the pistils and fertilization was accomplished within 8 h after pollination (HAP) in control cross. Even though delay in pollen tube was a common phenomenon in all the four crosses successful fertilization was observed in crosses involving G. triphyllum and G. armourianum, as they reached the ovary at 24 HAP. In crosses with G. davidsonii and G. thurberi, pollen tubes failed to reach the ovary even at 24 HAP indicating the presence of strong stylar and ovarian incompatibility. Measures to overcome such barriers to interspecific hybridization in the incompatible crosses are discussed.  相似文献   

Dyeing of cotton yarn with five water soluble fungal pigments obtained from five fungi   总被引：1，自引：0，他引：1  

Palanivel Velmurugan  Myung-Jun Kim  Jun-Sic Park  Kannan Karthikeyan  Perumalsamy Lakshmanaperumalsamy  Kui-Jae Lee  Yool-Jin Park  Byung-Taek Oh 《Fibers and Polymers》2010,11(4):598-605

The present study aimed to assess the potentiality of water soluble fungal pigments for dyeing on cotton yarn. Five different shades of pigments were extracted from Monascus purpureus, Isaria farinosa, Emericella nidulans, Fusarium verticillioides, and Penicillium purpurogenum using ethanol. Maximum concentration of pigment was obtained from Monascus purpureus (red, 25.02±1.6 UA) followed by Penicillium purpurogenum (yellow, 23.05±0.3 UA). The optimum dyeing condition was observed at a pigment concentration of 1 gram, pH 5, temperature 80 °C, time duration 90 min, and a liquor ratio of 1:30 was found to be the optimal for dyeing. Maximum uptake of 80 % was achieved with Monascus purpureus red pigment. Moreover, the effect of mordant in dyeing was evaluated by different mordanting methods. A strong variation in shade and color depth could be achieved by using pre-mordanting method with alum and ferrous sulfate giving better wash fastness properties when compared with post-mordanting or without a mordant.  相似文献   

Efficacy of intra-muscular analgesics for acute pain in sheep   总被引：1，自引：0，他引：1  

C. GRANT  RN UPTON†  TR KUCHEL‡ 《Australian veterinary journal》1996,73(4):129-132

The analgesic action of intramuscularly injected buprenorphine, methadone, flunixin meglumine and xylazine was examined in sheep, using algesimetry based on a leg withdrawal response to an electrical stimulus. No analgesic response was detected for buprenorphine, methadone or flunixin meglumine. Only the αaL2-adrenoceptor agonist, xylazine, produced an analgesic response. The current required to elicit a response increased by 170% (4.5±0.43 mA to 12.23±1.14 mA; mean±SE) after a dose of 0.05 mg/kg xylazine; by 180% (4.73±0.3 mA to 13.28±2.35 mA) after 0.1 mg/kg; and by 510% (4.52±0.29 mA to 27.63±3.89 mA) after 0.2 mg/kg. Intramuscular xylazine appears to be an effective analgesic agent for acute pain in the sheep and further investigation into ideal administration regimens and dosage may provide more detailed information on relationships between dose, analgesic and sedative effects. The findings also suggest that some common analgesic agents, and opioids in particular, may be ineffective for the management of acute pain in sheep and that any analgesic should be administered only on the basis of its proven efficacy in that species.  相似文献   

Influence of different handling methods and crating periods on plasma corticosterone concentrations in broilers     

G. Kannan  J. A. Mench 《British poultry science》1996,37(1):21-31

1. Experiments were conducted to determine whether different handling methods and crating periods differentially affect plasma corticosterone (CS) concentrations in 6 to 7‐week‐old broilers.

2. Broilers were subjected to 1 of 3 handling methods for 2 min: (i) 3 birds held in an inverted position in one hand (multiple inverted, MI), (ii) 1 bird held in an inverted position (single inverted, SI), or (iii) upright handling (U), which consisted of holding a bird gently with both hands in an upright position.

3. In experiment 1 birds were returned to their respective pens after handling and in experiment 2 they were crated for up to 4 h after the imposition of handling. In experiment 2 food deprived (FD) and fully fed (FF) uncrated birds were also sampled as controls. Blood samples were collected immediately after handling and at 1‐h intervals after handling or handling and crating.

4. In experiment 1, MI and SI birds had higher CS concentrations than U birds.

5. In experiment 2, there were no significant differences in CS concentrations of crated birds despite the different handling treatments. FD birds had higher mean CS concentrations than FF birds, although not as high as those of crated birds. CS concentrations peaked at 3 h after crating. Birds showed predominantly resting behaviour after crating.

6. These results suggest that handling stress can be reduced in broilers by the use of upright handling. However, the methods of handling is not important in influencing CS concentrations if the birds are crated after handling, either because crating is a more potent stressor than handling or due to stressor additivity.  相似文献   

Influence of dietary condensed tannins from sericea lespedeza on bacterial loads in gastrointestinal tracts of meat goats     

J.H. Lee  M. Vanguru  G. Kannan  D.A. Moore  T.H. Terrill  B. Kouakou 《Livestock Science》2009,126(1-3):314-317

This research assessed the potential use of a low input forage containing a high amount of condensed tannins (CT) to reduce foodborne pathogens prior to slaughter of meat goats. In a completely randomized design, twenty Kiko × Spanish intact male kids (BW = 19.2 ± 0.74 kg) were fed ground sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours) G. Don; 2 pens], a high-CT legume, or bermudagrass hay [BG; Cynodon dactyon (L.) Pers.; 2 pens], at 75% of daily intake with a corn-based supplement (25% of intake) for 14 weeks (n = 10 goats/treatment). At the end of the feeding trial, the animals were slaughtered using standard procedures. Immediately after evisceration, rumen and rectal samples were collected to assess bacterial loads and volatile fatty acids in the rumen. Concentrations of rumen volatile fatty acids were significantly different between dietary treatments. Goats fed SL hay had higher (P < 0.05) contents of butyric (8.66 vs 7.16 mM), isobutyric (1.94 vs 1.44 mM), isovaleric (3.03 vs 2.13 mM), and valeric (1.43 vs 1.07 mM) acids than those fed BG hay; however, the content of acetic acid (78.6 vs 64.4 mM) was higher (P < 0.05) in the BG-fed groups than in SL-fed groups. Escherichia coli (2.33 vs 1.13 log₁₀ CFU/g) counts of rumen contents were higher (P < 0.05) in the SL-fed group compared with the BG-fed group. However, E. coli counts in feces were not different (P > 0.05) between dietary treatments. The high-CT influenced (P < 0.05) total plate counts in the feces; and the total plate counts in feces of SL- and BG-fed goats were 4.95 and 6.57 log₁₀ CFU/g, respectively. The results indicated that high CT in the diet might influence rumen volatile fatty acid composition, but might not reduce the bacterial loads in gastrointestinal tracts of meat goats.  相似文献   

Diversity in selected wild and cultivated species of pigeonpea using RFLP of mtDNA   总被引：2，自引：0，他引：2  

S. Sivaramakrishnan  Seetha Kannan  L.J. Reddy 《Euphytica》2002,125(1):21-28

Diversity in 28 accessions representing 12 species of the genus, Cajanus arranged in 6 sections including 5 accessions of the cultivated species, C. cajan, and 4 species of the genus Rhyncosia available in the germplasm collection at ICRISAT was assessed using RFLP with maize mtDNA probes. Cluster analysis of the Southern blot hybridization data with 3 restriction enzymes – 3 probe combinations placed the genus Rhyncosia in a major group well separated from all the species belonging to the genus Cajanus. Within the genus Cajanus, the 4 accessions of C. platycarpus belonging to section Rhynchosoides formed a separate group in contrast to those in other sections of pigeonpea. In the section, Cajanus all the 5 accessions of C. cajan were grouped together and C. cajanifolius belonging to the same section was in a subgroup by itself closer to the main group. The four accessions of C. scarabaeoides, were together and the other species belonging to section Cantharospermum were in different subgroups. The intra-specific variation was seen even within accessions of certain pigeonpea wild species such as C. scarabaeoides, C. platycarpus, C. acutifolius, and even the cultivated species of C. cajan. This study suggests that RFLP of mtDNA can be used for the diversity analysis of pigeonpea and it gives some indications on the maternal lineage among the species. The variations in the mitochondrial DNA hybridization patterns also suggest the extensive rearrangement of the organelle genome among the Cajanus species. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献