Effect of polyolefin resin coated slow release iron fertilizer and its methods of application on rice production in calcareous soil

Experiment was carried out to evaluate the, efficiency of different iron sources including polyolefin resin coated slow release Fe fertilizer (PRCCFe) and its methods of application on the performance of rice var. Swarna during rainy seasons of 2001 and 2002 under calcareous soil at Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India. The pots were filled with 10 kg calcareous soil having high CaCO₃ (36.32%) and low iron contents (1.45 pp—less than critical limit). The experimental treatments comprised five iron sources (NPK + 100% pyrite, NPK + 100% polyolefin resin coated slow release Fe (PRCSRFe), NPK + 50% pyrite + 50% PRCSRFe, NPK + 75% pyrite + 25% PCRSRFe, and NPK + 25% pyrite + 75% PCRSRFe and two methods of application (uniform and co-situs) including one control (NPK only). These 11 treatment combinations were laid out in Completely Randomized Block Design (CRBD) replicated thrice. The two methods of iron application did not differ significantly with respect to crop yield though higher yield was recorded with co-situs application. Among the Fe sources, application of iron 75% through to + 25% through polyolefin resin coated slow release Fe fertilizer produced the highest grain yield.     

Nitrous oxide (N<Subscript>2</Subscript>O)-reducing denitrifier-inoculated organic fertilizer mitigates N<Subscript>2</Subscript>O emissions from agricultural soils

The only known sink for nitrous oxide (N₂O) is biochemical reduction to dinitrogen (N₂) by N₂O reductase (N₂OR). We hypothesized that the application of N₂O-reducing denitrifier-inoculated organic fertilizer could enhance soil N₂O consumption while the disruption of nosZ genes could result in inactivation of N₂O consumption. To test such hypotheses, a denitrifier-inoculated granular organic fertilizer was applied to both soil microcosms and fields. Of 41 denitrifier strains, 38 generated ³⁰N₂ in the end products of denitrification (³⁰N₂ and ⁴⁶N₂O) after the addition of Na¹⁵NO₃ in culture condition, indicating their high N₂O reductase activities. Of these 41 strains, 18 were screened in soil microcosms after their inoculation into the organic fertilizer, most of which were affiliated with Azospirillum and Herbaspirillum. These 18 strains were nutritionally starved to improve their survival in soil, and 14 starved and/or non-starved strains significantly decreased N₂O emissions in soil microcosms. However, the N₂O emission had not been decreased in soil microcosms after inoculating with a nosZ gene-disruptive strain, suggesting that N₂O reductase activity might be essential for N₂O consumption. Although the decrease of N₂O was not significant at field scales, the application of organic fertilizer inoculated with Azospirillum sp. TSH100 and Herbaspirillum sp. UKPF54 had decreased the N₂O emissions by 36.7% in Fluvisol and 23.4% in Andosol in 2014, but by 21.6% in Andosol in 2015 (H. sp. UKPF54 only). These results suggest that the application of N₂O-reducing denitrifier-inoculated organic fertilizer may enhance N₂O consumption or decrease N₂O emissions in agricultural soils.     

Iron Uptake and Loading into Rice Grains

Iron (Fe) is an important micronutrient for living organisms. Fe deficiency severely impairs plant growth and is a widespread human dietary problem, with particularly high numbers of affected children and females. Rice (Oryza sativa) is a source of energy for more than half of the world’s population. Thus, understanding the mechanisms of Fe uptake and translocation in rice is of utmost importance in the development of rice varieties that are tolerant to low Fe availability and with high seed levels of Fe. In recent years, the mechanisms underlying Fe transport and homeostasis have been revealed, providing opportunities to increase the Fe content of rice grain. As excess Fe is toxic to cells, plants have developed sophisticated mechanisms to control Fe flow, making it difficult to alter Fe transport. Thus, choosing appropriate chelators and Fe transporters driven by appropriate promoters seems to be the key in developing rice that is tolerant to low Fe availability and which accumulates high grain levels of Fe. Many recent studies have been aimed at increasing the Fe content of rice. Here, we summarize these efforts and review recent progress in understanding the mechanisms of Fe transport.     

Conditioned fear-related ultrasonic vocalizations are emitted as an emotional response

Ultrasonic vocalizations (USVs) are observed along with freezing behavior when rats are placed under fearful situation. Coping style with stress is categorized into two forms, namely passive and emotional avoidance and active operant avoidance. In this study, fear-induced USV was compared between two conditioning protocols. Two groups of male Wistar rats were contextually conditioned for 10 days by exposing to the shock box. One group was shock-unavoidable and the other shock-avoidable by operant control of emitting the USVs. They were then proceeded to the extinction phase. As the results, the shock-unavoidable group emitted greater USV in both conditioning and extinction phases. The extinction burst, commonly seen in active learned responses, was not observed in either group. The duration of freezing was also longer in shock-unavoidable conditioned rats. These results suggest that under the shock-unavoidable condition, rats receive more stress and thus emit more USV. It is therefore concluded that fear-induced USV is an emotional and passive response to the stress, rather than being controlled in an operant-way.     

Effects of oral exposure of bisphenol A on mRNA expression of nuclear receptors in murine placentae assessed by DNA microarray

Bisphenol A (BPA), a candidate endocrine disruptor (ED), is considered to bind to estrogen receptors and to regulate expressions of estrogen responsive genes. It has also shown evidence of affecting the reproductive, immunological and nervous systems of mammalian embryos. However, the effects of BPA on placentae, a central organ of feto-maternal interlocution, are still unclear. To reveal the mechanisms of BPA effects on placentae in mammals, we compared the mRNA expression of 20 nuclear receptors between placentae of vehicle controls and those of orally BPA exposed pregnant mice by a DNA microarray technique. In murine placentae, mRNAs of 11 nuclear receptors were not detected. However, greater than 1.5 fold changes in mRNA expression of nine nuclear receptors between vehicle control and BPA treated mice were noted. Moreover, remarkable changes in mRNA expression of six non-nuclear receptor proteins were induced by BPA exposure. There were various differences in the effects of BPA on the expression of these mRNAs between the placentae with male embryos and those with female embryos. Such embryo-sex dependent differences are interesting and important pointers to understanding of the endocrine disrupting effect of BPA. The present data indicate that BPA affects the expression of nuclear receptor mRNAs in placentae and may disrupt the physiological functions of placentae.