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91.
Populations of predatory protozoa in field soils after 5 years of elemental s fertilizer application
The effect of 5 yr of repeated application of elemental S (S°) fertilizer on predatory protozoa in soil was investigated. Protozoa that feed on the bacteria Arthrobacter globiformis and Enterobacter aerogenes or the fungi Fusarium solani and Neurospora crassa were enumerated by most probable number (MPN) methods. The application of S° fertilizer reduced the microbial biomass and its activity in soil. Soils treated with 44kg S° ha−1 yr−1 for 5 yr exhibited a 30–71% decline in MPN of protozoa feeding on bacteria and more than a 84% decline in the population of mycophagous amoebae. This decline in protozoa populations parallelled changes in microbial biomass, especially in the case of mycophagous amoebae and fungal biomass. The adverse effect of repeated S° applications on microbial biomass and predatory protozoa was long lasting. Since nutrient transformations (e.g. mineralization) in soil are influenced by microbial interactions, our results suggest reduced nutrient turnover via microbial predation in S° treated soils. 相似文献
92.
This paper reports the results of wheat plants exposed to SO2. The SO2-treated and control plant samples were periodically analyzed with respect to their carbohydrate content, caloric values, phytomass accumulations and net primary productivity. An initial increase, but later decrease in all these parameters was recorded in SO2-treated plants. These effects in wheat plants have been interpreted in terms of energy budget of plants under SO2-stress condition. 相似文献
93.
Toxicity of various animal wastes, after mixing with deionized water, for 1 and 24 hr, was measured using Photobacterium phosphoreum. The EC50 values determined by the ‘microtox’ toxicity test showed that the aqueous extracts of all animal wastes were toxic and the toxicity increased in the order: cattle, horse, sheep, pig and poultry. The observed toxicity was found not to be influenced by the amount of kjeldahl-N, NO3 or NH4 present in the waste-extract. 相似文献
94.
The ability of fly ash to remove Omega Chrome Red ME (a chrome dye, mostly used in textile industries) from water has been studied. It has been found that low adsorbate concentration, small particle size of adsorbent, low temperature, and acidic pH of the medium favor the removal of chrome dye from aqueous solutions. The dynamics of adsorbate transport from bulk to the solid phase has been studied at different temperatures in light of the adsorption of dye on the outer surface as well as diffusion within the pores of fly ash. The applicability of Langmuir isotherm suggests the formation of monolayer coverage of dye molecules on the outer interface of adsorbent. The thermodynamics of chrome dye-fly ash system indicates spontaneous and exothermic nature of the process. The pronounced removal of chrome dye in the acidic range may be due to the association of dye anions with the positively charged surface of the adsorbent. 相似文献
95.
Field experiments on cotton with different forms of urea applied at rates of 40 and 80 kg N/ha were carried out. The results indicated that application of nitrogen increased plant height, dry matter accumulation, number of bolls per plant, seed cotton yield and nitrogen uptake. The proportion of dry matter and nitrogen in the stem was increased and that in the leaves was reduced by N application. Sulphur coated urea (all applied at sowing) was about the same in effect as N-Serve treated urea and gave significantly more seed cotton yield than untreated urea, neem cake treated urea and sulphur coated urea (applied in two splits). Nitrogen efficiency as expressed by kg seed cotton production per kg N applied was greater with 40 kg N/ha rate than with 80 kg N/ha. Sulphur coated urea (all applied at sowing) gave the highest nitrogen efficiency followed by N-Serve treated urea. 相似文献
96.
Takashi Ozawa Chandra Prasad Risal Ryoko Yanagimoto 《Soil Science and Plant Nutrition》2005,51(6):917-920
The contribution of an earthworm species ( Amynthas vittatus ) to the increase of the nitrogen content of soil was examined. Three specimens of adult earthworms were introduced into 300 g of soil (Gray Lowland soil, silty clay) supplemented with 1% carboxymethyl cellulose in a container and incubated for 32 d at 22°C in the dark. The contents of total-N, NH4 -N and NO3 -N, and the population of aerobic nitrogen-fixing bacteria in soil significantly increased after incubation with the earthworms, while the natural abundance of 15 N (δ15 N) in soil decreased. The amount of nitrogen in the earthworms did not decrease during the incubation in the microcosm. Both acetylene reduction activity of the microcosm and incorporation of 15 N to soil from atmospheric 15 N2 were significantly enhanced by the introduction of the earthworms into soil, though the observed increment of nitrogen in soil was much higher than the estimated one based on the nitrogen-fixing activity. The results obtained in the present study indicated that the earthworms increased the nitrogen content of soil, presumably due to the enhancement of the nitrogen-fixing activity of the soil from the microcosm by the earthworms. 相似文献
97.
Many farmers in southeast Asia are growing rice on unpuddled soil. This practice does not permit breaking of the deadlock of increase in productivity in spite of using high yielding varieties and practising all known scientific technologies. Furthermore, farmers do dry seeding which leads to heavy infestation of weeds and reduces response to other inputs. Similarly, in rice–wheat belt due to short turn around time farmers resort to broadcast sowing of wheat after rice and no data on benefits or otherwise of tillage are available. A field study was therefore conducted for 3 years (1993–1994 to 1995–1996) at the Indian Agricultural Research Institute, New Delhi to study the effect of tillage and seeding methods in rice–wheat cropping system. Treatments included four combinations of two puddling treatments (puddling and no puddling) and two methods of rice seeding (direct seeding and transplanting) in rice and two tillage treatments (zero and conventional tillage) in wheat. Results indicated that puddling increased grain yield of rice by 0.7–1 t ha−1 and of succeeding wheat by 0.2–0.4 t ha−1, straw yield of rice by 0.8–1.7 t ha−1 and of succeeding wheat by 0.1–1.0 t ha−1.
Puddling reduced water requirement of rice by 75 mm ha and increased net return of rice–wheat system by US $175 ha−1. Transplanted rice gave significantly higher grain and straw yields and net returns than direct seeded rice both on puddled and unpuddled seedbed. Conventional tillage in wheat also increased productivity of rice–wheat cropping system significantly over zero tillage after both puddled and non-puddled rice. Our results thus show that rice should be grown on puddled soil and wheat after rice should be sown after conventional tillage. 相似文献
98.
Ritika Gupta K.P. Sastry S. Banerjee G.R. Mallavarapu Sushil Kumar 《Genetic Resources and Crop Evolution》2001,48(6):629-636
Four new accessions (BSP1-4) of rose scentedgeranium Pelargonium graveolens were derivedfrom the spontaneous half-sib seed progeny of mostly sterilepopulations of the cultivar accession Bipuli. The seed producingplants of Bipuli had been growing among the populations of cultivaraccessions Hemanti and Kunti in the temperate agroclimate ofKodaikanal, Tamilnadu in India. The four new accessions were comparedwith the cultivar accessions Bipuli, Hemanti and Kunti in fieldexperiments under subtropical agroclimate of Lucknow, Uttar Pradeshfor essential oil yield and quality related traits and in terms oftheir RAPD profiles. The crop yield and essential oil parameters andDNA profiles of the four new accessions and three cultivar accessionsallowed the conclusion that the accessions BSP-1, BSP-2 andBSP-3 were Bipuli × Kunti hybrids and BSP-4was a Bipuli × Hemanti hybrid. The accession BSP-4demonstrated hybrid vigour in several of the essential oil yieldrelated traits; on average basis it out yielded other accessions by afactor of about 2.4. The essential oil of BSP-4 had 89%rhodinol content in which citronellol to geraniol ratio was 1:1 andthe contents of isomenthone, menthone, 10-epi--eudesmol, 6,9-guaiadiene, decanoic acid andisodecanoic acid were relatively lower than in the oils of accessionsBipuli and/or Hemanti. The present study has shown a way for thegeneration of new genotypes in rose scented geranium in which thecultivars have been vegetatively maintained for decades and thegenetic resources are scanty. 相似文献
99.
Mahipal S. Shekhawat Narpat S. Shekhawat Harish Kheta Ram Mahendra Phulwaria Amit Kumar Gupta 《Journal of Crop Science and Biotechnology》2011,14(2):133-137
An in vitro propagation method for female plants of Momordica dioica (Roxb.) has been established. The nodal segments were harvested and the cut ends of the explants were sealed with wax and
then surface sterilized and cultured. Bud breaking occurred on Murashige and Skoog’s (MS) agar-gelled medium + 2.0 mg L−1 6-Benzylaminopurine (BAP) + 0.1 mg L−1 Indole-3 acetic acid (IAA). The cultures were amplified by passages on MS medium supplemented with 1.0 mg L−1 BAP + 0.1 mg L−1 IAA. Further, shoot amplification (29.2 shoots per vessel) was achieved by subculturing of in vitro regenerated shoot clump on MS medium + 0.5 mg L−1 BAP + 0.1 mg L−1 IAA. The micropropagated shoots were subsequently transferred for root formation on half-strength MS medium + 2.0 mg L−1 Indole-3 butyric acid (IBA) with 89% success rate. The in vitro-regenerated shoots were also rooted ex vitro with 34% success. These plantlets were hardened in the greenhouse and transferred to the field. The established protocol
is suitable for true to type cloning of mature female plant of M. dioica. 相似文献
100.
discharge rats of Purkinje neurons were compared in control and hypothyroid adult rats. Purkinje neurons in hypothyroid rats fired significantly faster and were less sensitive to iontophoretically applied norepinephrine than those in control rats. The subsensitivity of the Purkinje neurons appeared to be primarily due to an alteration in the beta-receptor--adenylate cyclase complex, because the sensitivity of these cells to locally applied N6-monobutyryl adenosine 3'-5'-monophosphate (N6 cyclic AMP) did not change significantly. The sensitivity of the Purkinje neurons to norepinephrine could be restored in hypothyroid rats by administration of triiodothyronine. 相似文献