Carbon,nitrogen, and phosphorus stoichiometry mediate sensitivity of carbon stabilization mechanisms along with surface layers of a Mollisol after long-term fertilization in Northeast China

Journal of Soils and Sediments - Soil organic carbon (SOC) is an important parameter determining soil fertility and sustaining soil health. How C, N, and P contents and their stoichiometric ratios...     

Mild salinity improves sugar beet (Beta vulgaris L.) quality

Abstract

Sugar beet (Beta vulgaris L.) is cultivated mainly on saline soils. Low levels of salinity stimulate growth of this crop plant possibly due to production of broader leaves as sources of assimilates. In this work, six cultivars were studied under mild salinity (EC = 5.5 dS m^?1) in a field experiment to analyse its effect on growth parameters and yield of storage root and sugar accumulation. An attempt was also made to determine the contributing role of photosynthetic gas exchange in response of sugar beet plants to salinity. Production of greater leaf area in salinized plants occurred only transitionally in the early growth period; in progression of the growing season it was decreased, and at 3rd harvest (100 days after treatment) it was significantly lower compared with control plants without cultivar differences. Leaf chlorophyll fluorescence, net photosynthesis rate, and stomatal conductance did not change by salinity significantly. Although, at the end of growth season, leaf area and potential photosynthesizing component of salinized plants on the basis of leaf area (LAR) or weight (LWR) were significantly lower than for control plants, weight of storage root and sugar content were up to 90 and 37% higher than in control plants, respectively. Consequently, a considerable higher yield under mild salinity conditions in sugar beet is not attributable to higher leaf area or, therefore, higher photosynthetic capacity of whole plants. Indeed, the storage roots benefit from lower dry matter and surface production of shoot during the late growing season (because of lower nitrogen assimilation and a slight drought stress of salinized plants) and a change in dry-matter partitioning in favor of roots takes place. However, a possible special effect of Na on carbon allocation for storage and structure and involvement of growth regulators in the change of root-shoot allometry could not be excluded.     

The response of drought-tolerant sugar beet to salinity stress under field and controlled environmental conditions

Abstract

Thirty-four sugar beet drought-tolerant half-sib families were screened in greenhouse experiment under saline (16?dSm^?1) and normal conditions, and a subset of 10 tolerant genotypes were selected for evaluating of yield-related traits, Na⁺, K⁺, and α-amino-N nitrogen contents under saline field condition (12?dSm^?1). Drought-tolerant genotypes showed a different tolerance level under salt stress. Significant correlation was observed between EP2_s and STIEP2 in greenhouse with root yield (RY) in saline field condition. It should be possible that a simple measurement at 16?dSm^?1 in the greenhouse can be used as main part of sugar beet salt-tolerant breeding program. In total, genotypes SBSI-DR I-HSF14-P.23 (# 16) and 436B-HSF9-P.27 (# 26) were recognized as salt- and drought-tolerant genotypes with low Na⁺ and K⁺ contents in root and high white sugar content (WSC) and RY in field. A larger panel of genotypes to validate this kind of association is necessary.     

Optimizing row spacing in wheat cultivars differing in tillering and stature for higher productivity

Five wheat cultivars differing in tillering capacity and stature, Sahar-2006 (SH-06) (tall and low tillering), Faisalabad-2008 (FSD-08) (tall and low tillering), Lassani-2008 (LS-08) (medium stature and low tillering), Abdulstar-2002 (AS-02) (medium stature and high tillering) and Triple dwarf-1 (TD-1) (dwarf and low tillering), were planted in 10-, 20- and 30-cm spaced rows in a two-year study with same plant density. Higher grain yield in 20-cm spaced rows during both years and 30-cm spaced rows during the first year of the study in tall and low tillering wheat cultivars was attributed to more productive tillers, grains per spike and 1000-grain weight. However, the higher number of productive tillers resulted in better grain yield of the dwarf and low tillering cultivar under narrow row spacing. Higher leaf area index and crop growth rate were observed in 20- and 30-cm spaced rows 90 days after sowing, thereafter a drastic decrease was observed in 30-cm spaced rows. In conclusion, for harvesting maximum wheat productivity, tall and low tillering cultivars should be planted in 20-cm spaced rows. Medium stature and low tillering cultivars may be planted in 20 or 30-cm spaced rows, whereas low tillering dwarf cultivars should be planted in 10-cm spaced rows.     

Optimization of stocking density of freshwater prawn Macrobrachium rosenbergii (de Man) in carp polyculture in Bangladesh

A study was conducted to optimize stocking density of freshwater prawn, Macrobrachium rosenbergii, in carp polyculture for 3 months in 10 experimental ponds of 80 m². Five stocking densities of prawn, 2500, 5000, 7500, 10 000 and 12 500 ha^?1, were assigned to treatments T₁, T₂, T₃, T₄ and T₅ respectively. The densities of catla, Catla catla, rohu, Labeo rohita and silver carp, Hypophthalmicthys molitrix, were 2500, 5000, and 2500 ha^?1, respectively, in each treatment. Each treatment had two replicate ponds. The mean initial weights of prawn, catla, rohu and silver carp were 1.1±0.02, 8.28±0.1, 25.2±1.1 and 36.32±1.2 g respectively. A pelleted diet containing 30% protein was prepared using fish meal, meat and bone meal, mustard oilcake, rice bran, wheat bran and molasses, and was fed twice daily at a rate of 5% of fish biomass. Water quality parameters were measured fortnightly and the ranges of temperature, pH and dissolved oxygen were 27.5–1.3°C, 6.9–8.6 and 4.5–8.6 mg L^?1 respectively. Feed conversion ratios ranged from 2.05 to 2.20 among the treatments. Per cent survival (%) of prawns ranged from 72% to 78%, while it varied from 80% to 93%, 90% to 95% and 90% to 92% for catla, rohu and silver carp respectively. The results showed that there were no significant differences among the weight gains of prawn and carp in different treatments. However, the overall total production of prawn and fish together was significantly (P<0.05) higher in T₃ and T₄ compared with other treatments. The total production for 3 months ranged between 2618 and 2916 kg ha^?1. The production of prawn was significantly higher (361.3 kg ha^?1) in T₅ with a highest stocking density of 12 500 prawn ha^?1. Although there was no significant difference (P>0.05) between the total production of prawn and fish together in T₃ and T₄, the highest net profit (Tk. 69 006 ha^?1) was obtained in T₄. Therefore, from the result of the study it may be concluded that a stocking ratio of 4:1:2:1 of prawn:catla:rohu:silver carp at a total density of 20 000 ha^?1 may be recommended for prawn–carp polyculture in ponds.     

Effect of mixed feeding schedules with varying dietary protein levels on the growth of sutchi catfish, Pangasius hypophthalmus (Sauvage) with silver carp, Hypophthalmichthys molitrix (Valenciennes) in ponds

A 6‐month feeding trial was conducted in field condition using 10 farm ponds (400–600 m²) to investigate the effect of mixed feeding schedules on the growth of sutchi catfish, Pangasius hypophthalmus with silver carp, Hypophthalmichthys molitrix. Fish were stocked at a ratio of 80:20 (sutchi catfish, 4.9±0.5 g: silver carp, 12.0±0.8 g) at the total rate of 25 000 ha^?1. Two diets of high protein (30%, HP) and low protein (16%, LP) were prepared using locally available feed ingredients. Five different feeding schedules of high‐protein diet continuously (HP), low‐protein diet continuously (LP), 1‐day low–protein/1‐day high‐protein diet (1LP/1HP), 7 days low–protein/7 days high‐protein diet (7LP/7HP) and 14 days low–protein/14 days high‐protein diet (14LP/14HP) were tested. The fish were fed twice daily at the rate of 15%, 10%, 8% and 5% of their body weight for first, second, third month and rest of experimental period respectively. Feeding rate was calculated only on the basis of sutchi catfish weight only and was adjusted every 2 weeks according to weight gain. Fish fed LP and HP on alternate day (1LP/1HP) resulted in significantly (P<0.05) higher growth rate, feed utilization and production among the treatments. However, there were no significant differences (P>0.05) between the growth rates and production of fish fed HP regularly and fish fed 7 days LP followed by 7 days HP (7LP/7HP). Fish maintained on LP grew the least. The feed conversion ratio (FCR) values for sutchi catfish ranged between 2.04 and 2.79 with feeding schedule 1LP/1HP showing the best FCR. The total production of fish (including silver carp) ranged between 8310 and 12 422 kg ha^?1 6 months^?1 with 1LP/1HP feeding schedule resulting in the highest production and net profit. The study demonstrated that feeding fish continuously with HP is less economical. Thus, for profitable sutchi catfish culture with silver carp, farmers can use the mixed feeding schedule of alternate day feeding of LP and HP as a means of reducing feed costs.     

Prevalence, molecular diagnosis and treatment of Mycoplasma conjunctivae isolated from infectious keratoconjunctivitis affected Lohi sheep maintained at Livestock Experiment Station, Bahadurnagar, Okara, Pakistan

Mycoplasma conjunctivae are etiological agents of infectious keratoconjunctivitis (IKC), commonly known as pink-eye in domestic sheep, goats and other wild animals in many parts of the world. A few young Lohi lambs maintained at Livestock Experiment Station (LES), Bahadurnagar, Okara, Pakistan showed clinical signs and symptoms of conjunctivitis, keratitis, severe lacrimation and varying degree of blindness. During January to March, 2011, a total of 36 ocular swabs were collected from IKC affected animals and were processed for isolation, identification, and characterization of M. conjunctivae. Sixteen (44.44 %) out of 36 samples showed turbidity in PPLO broth. Twelve (75 %) out of 16 broth samples showed colony growth on PPLO agar. All 16 (44.44 %) out of 36 turbid broth samples, 12 (75 %) out of 16 cultured on agar plate samples, and 21 (59 %) out of 36 sheep ocular direct swab samples were found positive for M. conjunctivae through polymerase chain reaction test by using M. conjunctivae-specific primer pair McoF1 and McoR1 and detecting a 750 base pair fragment on agarose gel. Topical application of 0.5 % sterile solution of gentamycin (100 mg/ml) (Gentafar 10 %, FARVET, Netherlands) proved suitable for the treatment of IKC in Lohi lambs as all clinical signs of IKC disappeared after 5 days of treatment with this antibiotic. This is the first report about the prevalence, molecular diagnosis, and treatment of M. conjunctivae in Lohi sheep affected with infectious keratoconjunctivitis at LES, Bahadurnagar, Okara, Pakistan.     

Aurora A inhibition disrupts chromosome condensation and spindle assembly during the first embryonic division in pigs

As common overexpression of Aurora A in various tumours, much attention has focused on its function in inducing cancer, and its value in cancer therapeutics, considerably less is known regarding its role in the first cleavage division of mammalian embryos. Here, we highlight an indispensable role of Aurora A during the first mitotic division progression of pig embryos just after meiosis. The expression and spatiotemporal localization of Aurora A were initially assessed in pig embryos during the first mitotic division by Western blot analysis and indirect immunofluorescent staining. Then, the potential role of Aurora A was further evaluated using a highly selective Aurora A inhibitor, MLN8054, during this mitotic progression in pig embryos. Aurora A was found to express and exhibit a specific dynamic intracellular localization pattern during the first mitotic division in pig embryos. Aurora A was diffused in the cytoplasm at the prophase stage, and then exhibited a dynamic intracellular localization which was tightly associated with the chromosome and spindle dynamics throughout subsequent mitotic phases. Inhibition of Aurora A by MLN8054 treatment led to the failure of the first cleavage, with the majority of embryos being arrested in prophase of the mitotic division. Further subcellular structure examination showed that Aurora A inhibition not only led to the failure of spindle microtubule assembly, but also resulted in severe defects in chromosome condensation, accompanied by an obvious decrease in p-TACC3(S558) expression during the prophase of the first mitosis. Together, these results illustrated that Aurora A is crucial for both spindle assembly and chromosome condensation during the first mitotic division in pig embryos, and that the regulation of Aurora A may be associated with its effects on p-TACC3(S558) expression.     

Different models for evaluation of growth traits and Kleiber ratio in an experimental flock of Iranian fat-tailed Afshari sheep

Records for Afshari sheep were retrieved from data collected between 2000 and 2005 at the Zanjan University experimental flock, at Zanjan, Iran. (Co)variance components and corresponding genetic parameters for birth weight (BW), weaning weight (WW), 6-month weight (W6), average daily gain from birth to weaning (ADGa), from birth to 6 months (ADGb), from weaning to 6 months (ADGc), Kleiber ratio at weaning (WWKR) and Kleiber ratio at 6 months of age (W6KR) were estimated using univariate and bivariate analyses by the DFREML procedure. The Kleiber ratio, defined as growth rate/metabolic weight, has been suggested to be a useful indicator of growth efficiency and an indirect selection criterion for feed conversion. Estimates of direct heritability ( h ²) were 0.23, 0.27, 0.11, 0.22, 0.07, 0.01, 0.13 and 0.06 for BW, WW, W6, ADGa, ADGb, ADGc, WWKR and W6KR, respectively. Maternal genetic effects represented a relatively large proportion of the total phenotypic variance for BW ( m ² = 0.22), whereas maternal permanent environmental effects were significant for W6 ( c ² = 0.15), ADGb ( c ² = 0.16), ADGc ( c ² = 0.14) and W6KR ( c ² = 0.16). Results of bivariate analyses indicated the variable genetic correlations between traits. The largest positive genetic relationships were between adjacent measurements. The moderate estimates of h ² for early growth traits indicate that in Afshari sheep faster genetic improvement through selection is possible for these traits. In order to increase the efficiency of feed conversion, use of Kleiber ratio in selection programmes was recommended.     

Feed technology and production performance of Thai koi (Anabas testudeneus) in Bangladesh

ABSTRACT

Thai koi farming is relatively new in the aquaculture industry of Bangladesh. Costly industrial feed pellets is the main factor influencing the productivity of Thai koi (Anabas testudineus). Two types of feed, namely, floating and sinking, are commercially available in the country. The ingredients of both types of feed are more or less the same. Floating feed requires high technology, high pressure and temperature and hence is more expensive than sinking feed. Most of the Thai koi farmers use either floating or sinking feed, while some farmers use a mix of both types of feed. This article investigated the effects of these three feed types on Thai koi productivity using primary data collected from the Mymensingh district of Bangladesh. The performance of different feed types on productivity was investigated using the Cobb-Douglas production function and propensity score matching (PSM) methods. Floating feed led to the highest daily mean weight gain of fish, feed conversion ratios, and net returns. The regression and PSM results revealed that farmers using floating feed produced significantly higher quantity of fish per unit compared to those using the other feed types. The cost of feed per hectare was higher in the farms using the floating feed, but these farms earned extra return from the additional investment, compared with the farms that use the other feed types. Thai koi farmers are advised to use floating feed to reap higher production and returns on investment.