Nutrient uptake,partitioning, and removal in two modern high-yielding Colombian rice genotypes

Abstract

The objective of this research was to determine the difference on growth between a rice cultivar with Clearfield^® technology (Only Rice 228) and a hybrid (Benja 1); to characterize nutrient uptake, distribution, accumulation and removal between these two commercial genotypes. Tests under shade house and field conditions were performed to estimate macro and micronutrient uptake patterns. Plants were sampled at nine growth stages (emergence, initiation of tillering, active tillering, initiation of panicle primordia, booting, flowering, milky, soft dough and mature grain) and divided into different organs for nutrient determination. The results showed that “Benja 1” plants (92 d) had a shorter cycle than “Only Rice 228” (OR 228) plants (118 d). “OR 228” exhibited a greater biomass production (16.575?kg ha^?1 vs. 12.621?kg ha^?1) in field. The nutrient acquisition was faster in the hybrid Benja 1 between tillering initiation and the milky grain stage in which the N, K, Ca, Mg, Mn, B, and Cu uptake was more evenly and highly distributed throughout these stages in both conditions. “Benja 1” showed a higher nutrient harvest index (HI). HI values above 50% (P (62%), N (61%), Cu (67%), S (55%), and Mg (52%)) were found in Benja 1 under field conditions. The results also highlight Si removal in both rice genotypes, in which Benja 1 stands out. These results provide information on the nutrient uptake and partitioning of modern rice genotypes, and give the knowledge to optimize fertilizer programs and timing recommendations for rice biomass and grain production in Colombia.     

The combined effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and the phytoestrogen genistein on steroid hormone secretion,AhR and ERβ expression and the incidence of apoptosis in granulosa cells of medium porcine follicles

Low doses of endocrine disrupting chemicals (EDCs) used in combination may act in a manner different from that of individual compounds. The objective of the study was to examine in vitro effects of low doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 100 pM) and genistein (500 nM) on: 1) progesterone (P₄) and estradiol (E₂) secretion (48 h); 2) dynamic changes in aryl hydrocarbon receptor (AhR) mRNA and protein expression (1, 3, 6, 24 and 48 h); 3) dynamic changes in estrogen receptor β (ERβ) mRNA and protein expression (1, 3, 6, 24 and 48 h); and 4) induction of apoptosis in porcine granulosa cells derived from medium follicles (3, 6 and 24 h). TCDD had no effect on P₄ or E₂ production, but potentiated the inhibitory effect of genistein on P₄ production. In contrast to the individual treatments which did not produce any effects, TCDD and genistein administered together decreased ERβ and AhR protein expression in granulosa cells. Moreover, the inhibitory effect of TCDD on AhR mRNA expression was abolished by genistein. The treatments did not induce apoptosis in the cells. In summary, combined effects of low concentrations of TCDD and genistein on follicular function of pigs differed from that of individual compounds. The results presented in the current paper clearly indicate that effects exerted by low doses of EDCs applied in combination must be taken into consideration when studying potential risk effects of EDCs on biological processes.     

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生活在声色犬马、信息狂暴的时代,总觉得自己好像在不自觉地跟着一些风儿瞎跑,但是每每静下心来,总会发觉自己原来是莫名的肤浅。面对着时下那些形形色色的休闲方式,虽谓之时尚,但让人总感觉是在用身体上片刻的修整甚或疲惫来换取劳累不堪的心情一阵解脱,然而须臾之后,心灵却仍     

Response of balsam fir and hemlock roots to injuries

Drill wounds in balsam fir and hemlock roots activated the nonspecific resistance mechanisms of compartmentalization in wood and necrophylactic periderm in bark. Tangential bands of resin ducts localized around the wounds constituted the barrier zones in the secondary xylem of conifer roots. Barrier zones were more extensive in roots which showed symptoms characteristic of invasion by fungi and bacteria after wounding. This observation supports an expanded definition of barrier zones; barrier zones may form not only in response to mechanical wounds but also in response to xylem injury caused by pathogens. Multiple bands of resin ducts were common in young xylem when bark lesions developed around wounds. Necrophylactic periderms isolared dead bark from living bark. Development of phellem cells with dark contents and thick suberized walls, typical of exophylactic periderm, followed initiation of necrophylactic periderm. The wound responses were similar in both balsam fir and hemlock.     

Pharmacokinetic‐pharmacodynamic modelling of intravenous buprenorphine in conscious horses

ObjectiveDescribe the pharmacokinetics of buprenorphine and norbuprenorphine in horses and to relate the plasma buprenorphine concentration to the pharmacodynamic effects.Study designSingle phase non-blinded study.AnimalsSix dedicated research horses, aged 3–10 years and weighing 480–515 kg.MethodsThermal and mechanical nociceptive thresholds, heart and respiratory rates and locomotor activity were measured before and 15, 30, 45 &; 60 minutes and 2, 4, 6, 8, 12 &; 24 hours post-administration of 10 μg kg⁻¹ buprenorphine IV. Intestinal motility was measured 1, 6, 12 &; 24 hours after buprenorphine administration. Venous blood samples were obtained before administration of buprenorphine 10 μg kg⁻¹ IV and 1, 2, 4, 6, 10, 15, 30, 45 &; 60 minutes, and 2, 4, 6, 8, 12 &; 24 hours afterwards. Plasma buprenorphine and norbuprenorphine concentrations were measured using a liquid chromatography-tandem mass spectroscopy (LC-MS/MS) assay with solid-phase extraction. A non-compartmental method was used for analysis of the plasma concentration–time data and plasma buprenorphine concentrations were modelled against two dynamic effects (change in thermal threshold and mechanical threshold) using a simple Emax model.ResultsPlasma buprenorphine concentrations were detectable to 480 minutes in all horses and to 720 minutes in two out of six horses. Norbuprenorphine was not detected. Thermal thresholds increased from 15 minutes post-buprenorphine administration until the 8–12 hour time points. The increase in mechanical threshold ranged from 3.5 to 6.0 Newtons (median: 4.4 N); and was associated with plasma buprenorphine concentrations in the range 0.34–2.45 ng mL⁻¹.Conclusions and clinical relevanceThe suitability of the use of buprenorphine for peri-operative analgesia in the horse is supported by the present study.     

Prevalence of feline immunodeficiency virus infection in domesticated and feral cats in eastern Australia

Serum samples from 340 pet cats presented to three inner city clinics in Sydney Australia, 68 feral cats from two separate colonies in Sydney, and 329 cattery-confined pedigree and domestic cats in eastern Australia, were collected over a 2-year period and tested for antibodies directed against feline immunodeficiency virus (FIV) using immunomigration (Agen FIV Rapid Immunomigration test) and enzyme-linked immunosorbent assay methods (Snap Combo feline leukaemia virus antigen/FIV antibody test kit, IDEXX Laboratories). Western blot analysis was performed on samples in which there was discrepancy between the results. Information regarding breed, age, gender, housing arrangement and health status were recorded for all pet and cattery-confined cats, while the estimated age and current physical condition were recorded for feral cats. The FIV prevalence in the two feral cat populations was 21% and 25%. The majority of FIV-positive cats were male (60-80%). The FIV prevalence in cattery-confined cats was nil. The prevalence of FIV in the pet cat sample population was 8% (27/340) with almost equal prevalence in 'healthy' (13/170) and 'systemically unwell' (14/170) cats. The age of FIV-positive pet cats ranged from 3 to 19 years; all FIV-positive cats were domestic shorthairs with outside access. The median age of FIV-positive pet cats (11 years) was significantly greater than the median age of FIV-negative pet cats (7.5 years: P<0.05). The prevalence of FIV infection in male pet cats (21/172; 12%) was three times that in female pet cats (6/168; 4%; P<0.05). With over 80% of this pet cat population given outside access and continued FIV infection present in the feral population, this study highlights the need to develop rapid, accurate and cost-effective diagnostic methods that are not subject to false positives created by concurrent vaccination against FIV. This is especially important in re-homing stray cats within animal shelters and monitoring the efficacy of the new vaccine, which has not been challenged against Australian strains. The absence of FIV within cattery-confined cats highlights the value in routine screening and indoor lifestyles. This study provides cogent baseline FIV prevalences in three cat subpopulations which can be used for appraising potential disease associations with FIV in Australia.     

Effect of silicon fertilizers on silicon accumulation in wheat

The effect of fertilization with silicon (Si) compounds on accumulation of Si in wheat (Triticum aestivum L.) has been studied. Wheat plants were grown under identical growing conditions, but subjected to fertilization with various Si compounds (pyrolitic fine silica particles [aerosil®], sodium silicate, silica gel), and the Si content of the above ground plants was analyzed via X‐ray microanalysis (EDX) and atomic‐absorption spectroscopy (AAS). Silicon was predominantly deposited in the epidermis cells of the leaves and their cell walls. The efficiency of the Si compounds used as fertilizers to augment the Si content of the plants increased in the order sodium silicate > silica gel > aerosil® and thus seemed to correlate with the ease of formation of orthosilicic acid from these compounds.