Lettuce (Lactuca sativa L.) growth,yield and quality response to nitrogen fertilization in a non-circulating hydroponic system     

R. I. S. Mahlangu  D. Sivakumar  P. Soundy  J. Jifon 《Journal of plant nutrition》2016,39(12):1766-1775

The objective of this study was to determine the effect of nitrogen fertilization rate on growth and quality of leafy lettuce grown during the winter season in non-circulating hydroponic system. Plants were subjected to seven nitrogen (N) concentrations, i.e. 0, 30, 60, 90, 120, 150 and 180 mg L^?1 N using ammonium nitrate. Nitrogen treatments did not have a significant effect on leaf fresh and dry mass, root fresh and dry mass, number leaves and leaf area. Leaf ascorbic acid and total phenolic content, and antioxidant capacity peaked at 100 and 120 mg L^?1 N, whereas leaf chlorophyll concentration linearly increased with increasing N application. The results indicate that a solution N concentration of 100 and 120 mg L^?1 may be sufficient to improve growth, yield and quality parameters of leafy lettuce grown in non-circulating hydroponic system.  相似文献   

Spectral reflectance indices as proxies for yield potential and heat stress tolerance in spring wheat: heritability estimates and marker-trait associations     

Caiyun LIU  Francisco PINTO  C. Mariano COSSANI  Sivakumar SUKUMARAN  Matthew P. REYNOLDS 《农业科学与工程前沿(英文版)》2019,6(3):296

The application of spectral reflectance indices (SRIs) as proxies to screen for yield potential (YP) and heat stress (HS) is emerging in crop breeding programs. Thus, a comparison of SRIs and their associations with grain yield (GY) under YP and HS conditions is important. In this study, we assessed the usefulness of 27 SRIs for indirect selection for agronomic traits by evaluating an elite spring wheat association mapping initiative (WAMI) population comprising 287 elite lines under YP and HS conditions. Genetic and phenotypic analysis identified 11 and 9 SRIs in different developmental stages as efficient indirect selection indices for yield in YP and HS conditions, respectively. We identified enhanced vegetation index (EVI) as the common SRI associated with GY under YP at booting, heading and late heading stages, whereas photochemical reflectance index (PRI) and normalized difference vegetation index (NDVI) were the common SRIs under booting and heading stages in HS. Genome-wide association study (GWAS) using 18704 single nucleotide polymorphisms (SNPs) from Illumina iSelect 90K identified 280 and 43 marker-trait associations for efficient SRIs at different developmental stages under YP and HS, respectively. Common genomic regions for multiple SRIs were identified in 14 regions in 9 chromosomes: 1B (60–62 cM), 3A (15, 85–90, 101– 105 cM), 3B (132–134 cM), 4A (47–51 cM), 4B (71– 75 cM), 5A (43–49, 56–60, 89–93 cM), 5B (124–125 cM), 6A (80–85 cM), and 6B (57–59, 71 cM). Among them, SNPs in chromosome 5A (89–93 cM) and 6A (80–85 cM) were co-located for yield and yield related traits. Overall, this study highlights the utility of SRIs as proxies for GY under YP and HS. High heritability estimates and identification of marker-trait associations indicate that SRIs are useful tools for understanding the genetic basis of agronomic and physiological traits.  相似文献   

Urine levels of luteinizing hormone as predictor of the period of ovulation for advantage of timed‐artificial insemination in murrah buffalo (Bubalus bubalis)          下载免费PDF全文

RM Selvam  D Singh  MA Akbarsha  G Archunan 《Reproduction in domestic animals》2017,52(3):517-521

Assessment of urine levels of luteinizing hormone (LH) for predicting the reproductive status of animals is in practice. The aim of this study was to predict the period of ovulation based on the urine levels of LH for timed‐artificial insemination to increase the conception rate in buffaloes, which are naturally silent‐oestrous animals. Level of LH in urine was assessed using ELISA, and a cut‐off LH concentration for prediction of ovulation period was obtained using receiver operating characteristic analysis. Artificial insemination was performed before‐ and after ‐positive prediction of ovulation period adopting this method, and the rates of conception were assessed. Urine LH level of 105 mIU/ml (n = 14) was derived as a cut‐off concentration which predicts the ovulation period. The buffaloes in the positively predicted group (day 1 or 2) inseminated via intracervical route had an increase in the conception rate (83.33%); however, the insemination in the before‐positive‐prediction group resulted in poor conception rates (day 0; 16.66%) compared to that of the naturally inseminated group (day 0; 75.0%). In conclusion, the urinary LH would possibly be a fairly reliable predictor of the ovulation period. The day when cut‐off LH concentration is obtained may be taken as the most favourable time for artificial insemination, so as to attain a much better rate of conception in the buffalo.  相似文献   

Radical scavenging and reducing ability of tilapia (Oreochromis niloticus) protein hydrolysates     

Raghavan S  Kristinsson HG  Leeuwenburgh C 《Journal of agricultural and food chemistry》2008,56(21):10359-10367

Enzymatically hydrolyzed fish protein hydrolysates could be used as a source of antioxidative nutraceuticals. In our current work, we have investigated alkali-solubilized tilapia ( Oreochromis niloticus) protein hydrolysates for their ability to scavenge reactive oxygen species (ROS) and for their reducing power. Tilapia protein isolate was prepared by an alkaline solubilization technique and used as a substrate for enzyme hydrolysis. Cryotin, protease A 'Amano' 2, protease N 'Amano', Neutrase and Flavourzyme, were used separately to determine their effectiveness in hydrolyzing tilapia protein isolate. ROS scavenging ability was quantified using an isoluminol enhanced chemiluminescent assay in the presence of a) hydrogen peroxide or b) mononuclear cells isolated from human blood. Ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) of the hydrolysates using 2, 2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) or 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), were also investigated. Results showed that, in general, the TEAC, FRAP values and ROS scavenging ability of the hydrolysates increased with an increase in the degree of hydrolysis. Among the different hydrolysates, those prepared using Cryotin were most effective and Amano A2 hydrolysates were least effective in scavenging ABTS*(+) and ROS generated by hydrogen peroxide. However, FRAP assay showed that hydrolysates prepared using Flavourzyme were most effective, and Amano N and Neutrase hydrolysates were least effective in reducing ferric ions. No significant difference was observed among the hydrolysates produced with different enzymes in their ability to scavenge ROS generated by phorbol myristate acetate stimulated mononuclear cells. These results shed light on the in vitro ROS scavenging ability of alkali solubilized tilapia protein hydrolysates, as well as potential nutraceutical use of these hydrolysates.  相似文献   

A new strain of white spot syndrome virus affecting Litopenaeus vannamei in Indian shrimp farms          下载免费PDF全文

S Sivakumar  S Vimal  S Abdul Majeed  S Santhosh Kumar  G Taju  N Madan  T Rajkumar  S Thamizhvanan  K V Shamsudheen  V Scaria  S Sivasubbu  A S Sahul Hameed 《Journal of fish diseases》2018,41(7):1129-1146

White spot syndrome virus (WSSV)‐infected shrimp samples collected from grow‐out ponds located at Nellore, Andhra Pradesh, India, showed WSSV negative and positive by PCR using primer sets specific to ORF119 and VP28 gene of WSSV, respectively. This indicated the deletion of genetic fragments in the genome of WSSV. The WSSV isolate along with lab strain of WSSV was subjected to next‐generation sequencing. The sequence analysis revealed a deletion of 13,170 bp at five positions in the genome of WSSV‐NS (new strain) relative to WSSV‐TH and WSSV‐LS (lab strain). The PCR analysis using the ORF's specific primer sets revealed the complete deletion of 10 ORFs in the genome of WSSV‐NS strain. The primer set was designed based on sequence covering ORF161/162/163 to amplify a product of 2,748 bp for WSSV‐LS and 402 bp for WSSV‐NS. Our surveillance programme carried out since 2002 revealed the replacement of WSSV‐LS by WSSV‐NS in Indian shrimp culture system.  相似文献   

Multiple infections caused by white spot syndrome virus and Enterocytozoon hepatopenaei in pond‐reared Penaeus vannamei in India and multiplex PCR for their simultaneous detection     

S. Thamizhvanan  S. Sivakumar  S. Santhosh Kumar  D. Vinoth Kumar  S. Suryakodi  K. Balaji  T. Rajkumar  S. Vimal  S. Abdul Majeed  G. Taju  A. S. Sahul Hameed 《Journal of fish diseases》2019,42(3):447-454

White leg shrimp, Penaeus vannamei, were collected on a monthly basis from grow‐out ponds located at Tamil Nadu and Andhra Pradesh states along the east coast of India for screening of viral and other pathogens. Totally 240 shrimp samples randomly collected from 92 farms were screened for white spot syndrome virus (WSSV), infectious hypodermal and haematopoietic necrosis virus (IHHNV), infectious myonecrosis virus (IMNV) and Enterocytozoon hepatopenaei (EHP). The number of shrimp collected from shrimp farms ranged from 6 to 20 based on the body weight of the shrimp. All the shrimp collected from one farm were pooled together for screening for pathogens by PCR assay. Among the samples screened, 28 samples were WSSV‐positive, one positive for IHHNV and 30 samples positive for EHP. Among the positive samples, four samples were found to be positive for both WSSV and EHP, which indicated that the shrimp had multiple infections with WSSV and EHP. This is the first report on the occurrence of multiple infections caused by WSSV and EHP. Multiplex PCR (m‐PCR) protocol was standardized to detect both pathogens simultaneously in single reaction instead of carrying out separate PCR for both pathogens. Using m‐PCR assay, naturally infected shrimp samples collected from field showed two prominent bands of 615 and 510 bp for WSSV and EHP, respectively.  相似文献   

Ultrasonic studies on lamivudine: beta-cyclodextrin and polymer inclusion complexes     

Selvam AP  Geetha D 《Pakistan journal of biological sciences: PJBS》2008,11(4):656-659

The aim of the present study is to enhance the solubility and stability of drugs in addition of water-soluble polymer and carbohydrate complexes. The data show that the polymer polyvinyl alcohol (PVA) interacts with the free Lamivudine and with the Lamivudine; beta-cyclodextrin (beta-CD) inclusion complex, in both cases with particular intermolecular interaction was studied using ultrasonic technique under different concentrations at a temperature 303 K. Consequently, the reason of this study was to improve the biological performance of the drug through enhancing its solubility and stability. The binary and ternary mixtures prepared inclusion complexes of Lamivudine in beta-CD and PVA. The presence of PVA, changes the drug: beta-CD interaction, a Lamivudine: beta-CD: PVA complex was formed. In addition, the presence of PVA produces a strong increase in the binding constant at a particular concentration (1.25%). In the ternary complex, the Lamivudine is wrapped at both ends for the beta-CD. In this complex, the polymer seems to act as a bridge between both beta-CD molecules that bind the Lamivudine.  相似文献   

Micropropagation of Eucalyptus camaldulensis for the production of rejuvenated stock plants for microcuttings propagation and genetic fidelity assessment     

K. Shanthi  V. K. W. Bachpai  S. Anisha  M. Ganesan  R. G. Anithaa  V. Subashini  M. Chakravarthi  V. Sivakumar  R. Yasodha 《New Forests》2015,46(3):357-371

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The first survey of Theileria orientalis infection in Mongolian cattle     

Altangerel K  Battsetseg B  Battur B  Sivakumar T  Batmagnai E  Javkhlan G  Tuvshintulga B  Igarashi I  Matsumoto K  Inokuma H  Yokoyama N 《Veterinary parasitology》2011,182(2-4):343-348

In the present study, we have surveyed the presence of a bovine Theileria protozoan, Theileria orientalis, in Mongolian cattle and engorging tick populations from selected provinces and districts in Mongolia. The percentages of infection in the cattle and ticks ranged from 8.8 to 66.6 and from 3.7 to 73.3, respectively, on a per district basis. The genetic diversity of T. orientalis isolates was also studied, based on the protozoan gene encoding a major piroplasm surface protein (MPSP). At least five genotypes (types 1, 3, 5, 7, and N-3) of T. orientalis were found to be circulating among the Mongolian cattle and tick populations. In particular, types 3 and N-3 were common in most of the districts examined, while a strong geographical relationship among the genotypes was not detected in the present study. This is the first epidemiological report describing the presence of T. orientalis infection in Mongolian cattle.  相似文献   

Salinity induced changes in photosynthetic pigment and antioxidant responses in Sesuvium portulacastrum     

Sivakumar T  Panneerselvam R 《Pakistan journal of biological sciences: PJBS》2011,14(21):967-975

The production of leaf and root antioxidant changes when exposed to saline conditions were investigated in the perennial halophyte Sesuvium portulacastrum L. Plants were grown with a nonsterilized soil and sterilized soil with 50 and 100% of sterilized seawater on 25, 55 and 85 Days After Planting (DAP). The plants were harvested on 30th, 60th and 90th DAP and used for analyzing the photosynthetic pigments, antioxidant enzyme activities viz., Superoxide dismutase (SOD; EC1.15.1.1) Ascorbate peroxidase (APX, EC 1.11.1.11) and non enzymatic antioxidant contents like ascorbic acid, alpha-tocopherol, reduced glutathione were determined. Plants exposed to salinity, either alone (SSW) sterilized seawater/unsterilized soil (USS) along with higher pigments, antioxidative enzymes and Na+ ions response. This tendency was generally more marked in SSW/USS plants when compared to SSW/SS plants. The concentration of SSW/SS was negatively correlated with the antioxidative capacity of the plant, either enzymatic or non enzymatic and K+ ions. These data suggest that the enhancement of the antioxidative response is of crucial significance for S. portulacastrum plants growing under saline conditions.  相似文献