Pushp Sharma

Triacylglycerol synthesis in developing kernels of groundnut as influenced by aliphatic alcohols

Abstract In developing groundnut ( Arachis hypogaea ) kernels, the most active period of lipid, chiefly triacylglycerol (TG) accumulation is between 15 and 35 days after podding (DAP). Between 5 and 15 DAP starch content was enhanced but declined thereafter up to maturity. With progressive development of kernels both phospholipids and free fatty acids decreased, whereas total glycerides continuously increased. At 15 DAP, [U- 14 C]fructose was incorporated into TG at a high rate. The incorporation of [1- 14 C]acetate into TG increased progressively during the active period of lipid accumulation. The rate of incorporation of the latter into TG was about three-fold greater than that of fructose. Addition of glycerol (0.5 mM) in the incubation medium stimulated lipid accumulation and is attributed to the limited availability of glycerol and other metabolites, especially during the active period of lipid accumulation in seed [15–35 DAP]. Foliar spray treatments with a mixture of aliphatic alcohols enhanced incorporation of [U- 14 C]fructose and [1- 14 C]acetate into TG of the developing kernels. The regulatory mechanisms involved in the stimulation of lipid accumulation are discussed.

Zinc Adsorption as Affected by Concentration, Temperature, and Time of Contact in the Presence of Electrolytic and Aqueous Medium in Benchmark Soils of Punjab in Northwest India

Adsorption of zinc (Zn) ions by soil colloids is significant because of its greater adsorbing surface, thus making it an important process in controlling Zn availability to plants. The adsorption processes depend upon a number of factors including temperature, pH, time of contact, clay content, and calcium carbonate content. Therefore, adsorption behavior of Zn was studied for eight benchmark soils of Punjab in northwestern India, varying widely in physical and chemical characteristics. The adsorption of Zn was studied at varying Zn concentrations, temperatures, and time of contact in the presence of 0.01 M sodium sulfate (Na2SO4) electrolyte and in aqueous medium. The greatest amount of Zn adsorbed in the presence of electrolyte and in aqueous medium (deionized water) was in arid series (Gahri Bhagi, Jassipauwali), followed by semi-arid series (Fatehpur, Kanjli) and subhumid series (Dhar, Chamror). The results revealed that irrespective of the soils, Zn adsorption increased with an increase in Zn concentration and decreased with an increase in temperature from 25 oC to 35 oC. Zinc adsorption was found to be greater in 0.01 M Na2SO4 solution as compared to aqueous medium. Further adsorption of Zn increased with increase in time of contact. The Zn adsorption data was well fitted to the Langmuir and Freundlich adsorption equations. The values of distribution coefficient Kd and partial molar free energy change ( ) were greater in the presence of 0.01 M Na2SO4 as compared to aqueous medium, suggesting that greater driving force is involved in adsorption of Zn in the presence of 0.01 M Na2SO4 as compared to aqueous medium.

Effects of Guaianolide derivative I on fibre initiation and elongation in Gossypium arboreum L. in relation to adverse effects of cool temperature

Cotton ovules collected during late September with prevalent night cool temperature (15°C), cultured at 30°C/15°C i.e. cycling temperatures in Beasley and Ting medium had very few epidermal cells showing bulging. Supplementing cultures with guaianolide derivative I (E-13 methyldehydrocostus lactone) promoted fibre initiation. At—1 day preanthesis (DPA), IAA oxidase activity declined in guaianolide-treated cultures but increased during the elongation phase and was enhanced during the secondary wall thickening phase. However, o-diphenol oxidase activity was adversely affected during the fibre initiation phase. The activities of all the other enzymes studied viz. acid invertase, phenylalanine ammonia lyase, β-glucosidase and IAA oxidase increased, except β-galactosidase, during the later phase in comparison with the controls. The present study indicates that guaianolide derivative I triggers early initiation and promotes fibre elongation by regulatin o-diphenols and IAA-oxidation levels, which in turn check wall loosening. Considerable enhancement in the soluble acid invertase activity by this compound suggests its role in apoplastic sucrose hydrolysis, thereby preventing its accumulation.

Nutrient Management for Sustaining Productivity of Sunflower-Based Cropping Sequence in Indian Semiarid Regions

ABSTRACT A comprehensive long-term study (2006–2010) was undertaken to develop a balanced and integrated nutrient supply system for sunflower-based cropping sequence considering the efficient utilization of residual and cumulative soil nutrient balance along with added fertilizers by the crops grown in rotation. The fertilizer application was done in potato and sunflower while greengram was raised as such on their residual effect. Significant response in yield was observed with 150% of the recommended nitrogen, phosphorus and potassium (NPK) or inclusion of farmyard manure (FYM) with the recommended NPK in the cropping sequence indicating 6.2–7.0% gain in system productivity over the existing recommendations. Each additional unit of P and K nutrition prompted system productivity by 18.9 and 11.0 kg kg−1 of applied nutrient, respectively. Apparent yield decline was observed in K and PK omission plots to the extent of 15.8 and 27.4% in potato, 10.5 and 23.9% in sunflower and 4.2 and 8.3% in greengram, respectively, compared to the recommended fertilization. The superiority of the FYM along with the recommended NPK (potato/sunflower) was evident on the overall profitability and sustainability of the system, highlighted by the significantly higher productivity (7.16 t SFEY ha−1), sustainability yield index (SYI; 0.76), production efficiency (PE; 27.85 kg SFEY ha−1 day−1) and net returns (2520 USD ha−1) with a B:C ratio of 2.91. Apparent change in potassium permanganate (KMnO4)-N was negative in all the treatments while N and P balance was positive with 150% NPK fertilization. Nutrient uptake exceeded the replenishment with 100% NPK application and maintained net negative soil nutrient stock for all the primary nutrients, indicating the need for revalidation of the existing recommendations in the system perspective. Conspicuous improvement in residual soil fertility in terms of maximum buildup of soil organic carbon (14%) and enhancement in soil KMnO4-N (4.2%), Olsen-P (19.4%), ammonium acetate (NH4OAc)-K (5.8%) and dehydrogenase enzyme activity (44.4%) was observed in FYM-treated plots over the initial values. The study suggested that the inclusion of legumes and FYM application with the recommended NPK in potato-sunflower cropping sequence will sustain the system’s productivity through the efficient use of nutrients, enhanced microbial activity and improved soil health while combating escalating prices of fertilizers as well as environmental issues in the Indo-Gangetic plains of India and similar environments.

Modelling approach to optimize sulphur fertilization in irrigated sunflower under semi-arid conditions in north-west India

Sulphur fertilization assumes substantial influence in improving the yield and quality of oilseed crops. The relationship between sunflower seed yield and sulphur dose applied was determined using quadratic model and the economically optimum sulphur dose was calculated via marginal analysis for yield maximization and profit over fertilizer cost. Economically optimum dose of sulphur for sunflower was found to be 32.99 and 38.95 kg/ha under semi-arid irrigated conditions during 2008 and 2009, respectively. Over-fertilized condition of S for maximum output did not bring out any significant advantage viewing almost identical seed yield both at physical and economic optimum of S indicating a saving of S from 2.8 to 4.0 kg/ha.