Temporal variation in mineral nitrogen in soil as influenced by incorporation of legume or cereal residues under submergence or well drained conditions     

R. Prasad  D. K. Singh  R. K. Singh 《Archives of Agronomy and Soil Science》2013,59(1-2):133-139

A laboratory study was conducted at the Indian Agricultural Research Institute, New Delhi on a sandy clay loam soil of pH 7.9 and organic C content of 0.34% to study the effect of incorporating Sesbania or Vigna legume residues or wheat straw at 15 and 30t ha^?1 on temporal variation in ammoniacal and nitrate‐N in soil under submergence and well drained conditions. Under submergence most mineral N was present as ammoniacal‐N, while under well drained conditions it was present as Nitrate‐N. The content of ammoniacal N in soil was the highest after 30 days of incubation and declined thereafter under submergence. On the other hand under well drained conditions the mineral‐N (mostly nitrate) content in soil at 30 DAI was very little and showed increases only later, reaching the highest level at 90 DAI. Application of wheat straw specially at 301 ha^?1 level resulted in immobilization of native soil‐N. These results show that rice which is grown under submergence can be transplanted soon after incorporation of legume residues, but for wheat or other crops which are grown under well drained condition a time interval of 30 days or more needs to be provided before sowing the crop.  相似文献   

Inhibition of mycelial growth and sporidial formation in the wheat pathogenNeovossia indica by a polyamine biosynthetic inhibitor     

P. P. Singh  S. Singh  Amarjit S. Basra  P. S. Bedi 《Phytoparasitica》1989,17(4):323-326

DL-α-Difluoromethylornithine (DFMO), a specific suicide inhibitor of the polyamine biosynthetic enzyme ornithine decarboxylase (EC 4.1.1.17), strongly inhibited mycelial growth and sporidial formation of the wheat pathogen,Neovossia indica, in vitro, while DL-α-difluoromethylarginine (DFMA), the analogous suicide inhibitor of arginine decarboxylase (EC 4.1.1.19), did not. The inhibited mycelial growth and sporidial formation were not only restored by putrescine (polyamine) addition, but were actually enhanced in the putrescine + DFMO cultures. Besides altering mycelial growth and morphology, DFMO also reduced the cell size drastically. The inhibition of fungal polyamine biosynthesis is discussed in relation to selective control of plant disease.  相似文献   

Studies on the systemicity of [14C]metalaxyl in cowpea (vigna unguiculata (L.) walp.)     

Uma S. Singh 《Pest management science》1989,25(2):145-154

[¹⁴C]metalaxyl applied to seeds, roots and leaves of cowpea was readily taken up by all plant parts and a major fraction of it was retained within the treated leaves and seeds but not in the roots. The fungicide exhibited ambimobility inside the plant. When applied to the middle of leaflets, metalaxyl mobilised towards proximal and distal parts of the leaflet. Intraleaflet movement seemed to result from translocation through veins and diffusion through cell walls and intercellular spaces. Accumulation of metalaxyl at tips and margins of primary leaves followed application to roots. Metalaxyl was readily extracted from most plant parts except cotyledons and only 0.8% of the fungicide applied as a seed treatment was recovered from 50-day-old plants.  相似文献   

Studies on pesticides based on coumarin. III. Synthesis and antifungal activity of substituted 4-methyl-coumarins and related compounds     

Rajvir Singh  Mrs V. Abrol  Bharat B. Gupta  Om P. Malik 《Pest management science》1988,23(2):103-107

A series of substituted 4-methylcoumarins was synthesised and the members tested for their toxicity towards mycelial growth of seven phytopathogenic fungi in culture. Rhizoctonia solani, Alternaria alternata and Fusarium solani exhibited maximum sensitivity to these compounds whereas Pythium aphanidermatum, Colletotrichum falcatum, Drechslera oryzae and Macrophomina phaseolina were relatively less sensitive. 6-Ethyl-3-n- propyl-7-hydroxy4-methylcoumarin ( I ) was relatively toxic towards all fungi except C. falcatum, P. aphanidermatum and M. phaseolina. The 6-n-butyl ( III ) and 6-(1, 1, 3, 3-tetramethylbutyl) ( VI ) derivatives were highly toxic to R. solani with EC₅₀, values of lμg ml^?1.  相似文献   

Studies on pesticides based on coumarin. II. Synthesis and antifungal activity of ten 2-alkyl-7, 8-dihydro-3-hydroxynaphtho[1,2-c]chromen-6-ones     

Bharat B. Gupta  Raj V. Singh  Om P. Malik  Hans R. Kataria 《Pest management science》1987,21(1):51-55

A series of 2-alkyl-7, 8-dihydro-3-hydroxynaphtho[1,2-c]chromen-6-ones was synthesised by the condensation of ethyl 3, 4-dihydro-1-oxonaphthalene-2-carboxylate with substituted phenols in the presence of POCl₃. The compounds were characterised and tested for their toxicity towards the mycelial growth of seven phytopathogenic fungi in culture. Drechslera oryzae, Rhizoctonia solani and Colletotrichum falcatum exhibited maximum sensitivity to these compounds whereas Macro-phomina phaseolina, Fusarium solani, Alternaria alternata and Pythium aphanidermatum were less sensitive. 2-Ethyl-7, 8-dihydro-3-hydroxy-naphtho[1,2-c]chromen-6-ones possessed greatest toxicity with EC₅₀ values ranging from 0.2 to 2.5 μg ml^?1 against all fungi except A. alternata and P. aphanidermatum.  相似文献   

Comparison of oil and phytosterol levels in germplasm accessions of corn, teosinte, and Job's tears     

Moreau RA  Singh V  Hicks KB 《Journal of agricultural and food chemistry》2001,49(8):3793-3795

Seeds of 49 accessions of corn (Zea mays ssp. mays), 9 accessions of teosinte (Zea species that are thought to be ancestors and probable progenitors to corn), and 3 accessions of Job's tears (Coix lacryma), obtained from a germplasm repository, were ground and extracted with hexane. Whole kernel oil yields and levels of four phytonutrients (free phytosterols, fatty acyl phytosterol esters, ferulate phytosterol esters, and gamma-tocopherol) in the oils were measured. Among the seeds tested, oil yields ranged from 2.19 to 4.83 wt %, the levels of ferulate phytosterol esters in the oil ranged from 0.047 to 0.839 wt %, the levels of free phytosterols in the oil ranged from 0.54 to 1.28 wt %, the levels of phytosterol fatty acyl esters in the oil ranged from 0.76 to 3.09 wt %, the levels of total phytosterols in the oil ranged from 1.40 to 4.38 wt %, and the levels of gamma-tocopherol in the oil ranged from 0.023 to 0.127 wt %. In general, higher levels of all three phytosterol classes were observed in seed oils from accessions of Zea mays ssp. mays than in seed oils from accessions of the other taxonomic groups. The highest levels of gamma-tocopherol were observed in teosinte accessions.  相似文献   

First report of a geminivirus causing leaf curl disease on Trigonella corniculata evidenced by PCR using degenerate primers     

S. K. Raj  S. K. Pandey  G. Chandra  B. P. Singh  R. K. Gupta 《EPPO Bulletin》2001,31(1):115-117

A leaf curl and mottle disease was observed naturally affecting plants of Trigonella corniculata. A geminivirus was detected in infected plants by PCR using degenerate geminivirus primers and by Southern hybridization with a probe specific to tomato leaf curl begomovirus. This is the first report of a member of the Geminiviridae naturally occurring in T. corniculata.  相似文献   

Ovipositional response ofHelicoverpa armigera to different cotton genotypes     

N. S. Butter  Surjit Singh 《Phytoparasitica》1996,24(2):97-102

The ovipositional response ofHelicoverpa armigera (Hübner) to different cotton varieties and species was studied under caged conditions. Maximum oviposition (51.6 eggs/female) was recorded on LH 900, a variety ofGossypium hirsutum, and minimum oviposition (3.0 eggs/female) on G 27, a variety ofG. arboreum. Oviposition, in general, was low (3 to 6.5 eggs/female) onarboreum cottons as compared withhirsutum. Of the number of factors found to affect the oviposition ofH. armigera, the trichome length on the upper surface of the leaf, rather than the density, was positively correlated (r = 0.687*). Among different months in the cropping season, oviposition was maximum (552.7) during April. Oviposition was higher on leaves than on other plant parts.  相似文献   

Purification and Biological Characterization of Host-Specific SV-Toxins from Stemphylium vesicarium Causing Brown Spot of European Pear     

Singh P  Bugiani R  Cavanni P  Nakajima H  Kodama M  Otani H  Kohmoto K 《Phytopathology》1999,89(10):947-953

ABSTRACT Culture filtrates of a pathogenic isolate (IT37) of Stemphylium vesicarium, causing brown spot of European pear, induced veinal necrosis only on pear leaves susceptible to the pathogen. Two host-specific toxins, SV-toxins I and II, were purified from culture filtrates of IT37 by successively using Amberlite XAD-2 resin adsorption, cellulose thin-layer chromatography, and high-performance liquid chromatography under three different sets of conditions. Susceptible cultivars showed veinal necrosis at a SV-toxin I concentration of 0.01 to 0.1 mug/ml, whereas resistant cultivars were insensitive to the toxin at 1,000 mug/ml. SV-toxins I and II caused a dose-dependent increase in electrolyte loss from susceptible leaf tissues. No increase in electrolyte loss was detected in leaf tissues from resistant cultivars. The results of physiological studies indicated that SV-toxins appear to have an early effect on plasma membranes of susceptible leaves. Spores of a nonpathogenic isolate induced necrotic lesions on susceptible leaves in the presence of a small amount of toxin. SV-toxins were detected in intercellular fluids obtained from diseased leaves after inoculation with the pathogen. The results indicate that SV-toxins I and II produced by S. vesicarium can be characterized as host-specific toxins.  相似文献   

The effects of duration and concentration of plasma progesterone on the fertility of post-partum cows treated with pregnant mare serum gonadotrophin and intravaginal progesterone     

RK MUNRO 《Australian veterinary journal》1989,66(2):43-45

The effects of duration of insertion of progesterone releasing devices (PRIDs) on the concentrations of plasma progesterone (plasma P4) and the relationship of these with fertility were examined respectively in ovariectomised and intact Bos taurus cattle. In experiment 1, ovariectomised cows (n = 14) were treated with PRIDs to produce high and low plasma P4 for 7 or 14 days giving 4 treatment groups designated H7, H14, L7 or L14. Mean plasma P4 in the H14 and L14 groups were 6.6 and 6.0 ng/ml respectively, during the first week and 5.4 and 3.8 ng/ml respectively, during the second. Mean plasma P4 of 6.3 and 4.2 ng/ml were observed in H7 and L7. In experiment 2, suckled cows (n = 171) received the same PRID treatments as cows in experiment 1, plus either 375 or 750 iu pregnant mare serum gonadotrophin, and subsequent calving rates were recorded. These were significantly lower after L7 than the other treatments (12% v 38%, P less than 0.025). These results showed that fertility after oestrus was closely related to plasma P4 observed before oestrus and indicated that treatment with progesterone for as little as 1 week can produce normal fertility providing plasma P4 attain a critical threshold during treatment.  相似文献