A comprehensive study on occurrence records of African neglected and underutilized weed species, Cleome gynandra L. (cat's whiskers) validating the ecogeographical range expansion in West Bengal, India

2019 ◽  
Vol 19 (4) ◽  
pp. 129-134
Author(s):  
Ekta Bhattacharya ◽  
Rahul Bose ◽  
Suparna Mandal Biswas
Author(s):  
K. Subramanya Sastry ◽  
Bikash Mandal ◽  
John Hammond ◽  
S. W. Scott ◽  
R. W. Briddon

2010 ◽  
Vol 76 (4) ◽  
pp. 292-294 ◽  
Author(s):  
S. K. Raj ◽  
S. K. Snehi ◽  
M. S. Khan ◽  
A. K. Tiwari ◽  
G. P. Rao

2017 ◽  
Vol 5 (3) ◽  
pp. 61-65 ◽  
Author(s):  
RajendraPrasad Chatterjee ◽  
◽  
Aroni Chatterjee ◽  
Nilanjan Chakraborty ◽  
Shyamalendu Chatterjee. ◽  
...  

2012 ◽  
Vol 92 (6) ◽  
pp. 1013-1020 ◽  
Author(s):  
David R. Clements ◽  
Antonio DiTommaso

Clements, D. R. and DiTommaso, A. 2012. Predicting weed invasion in Canada under climate change: Evaluating evolutionary potential. Can. J. Plant Sci. 92: 1013–1020. Many weed species have already advanced northward from the United States into Canada, and their number threatens to increase with warming trends under climate change. For many weed species, this range expansion can be attributed to evolutionary adaptation by northern populations occurring in areas experiencing warmer climates and longer growing seasons in recent decades. In this paper, we examine the potential for invasive plant species to be selected for one or more of 10 character traits: (1) high growth rate, (2) wide climatic or environmental tolerance, (3) short generation time, (4) prolific or consistent reproduction, (5) small seed size, (6) effective dispersal, (7) uniparental reproduction capacity, (8) no specialized germination requirements, (9) high competitive ability, and (10) effective defenses against natural enemies. If any one of these traits is selected for in an invasive species, it would provide the affected species with the potential for a more expansive invasion range than anticipated by models that assume a static genotype. Four weed species of interest exhibiting potential northward range expansion within North America were evaluated: an obligatory outcrossing annual dicot, Himalayan balsam (Impatiens glandilifera Royle), a mostly selfing annual dicot, velvetleaf (Abutilon theophrasti Medic.), a perennial dicot that reproduces via rhizomes but forms fertile hybrids, Japanese knotweed [Fallopia japonica (Houtt.) Ronse Decr.], and a primarily selfing perennial grass, johnsongrass [Sorghum halapense (L.) Pers.]. Evidence for potential evolutionary responses to climate change was observed among particular traits for each of the four species, despite population genetic differences. The population genetics of invasive plants are difficult to model, as is climate change itself, but consideration of weed evolution to whatever degree possible should lead to improved predictive power of such models.


Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.


Author(s):  
A. Singh ◽  
A. Dykeman ◽  
J. Jarrelf ◽  
D. C. Villeneuve

Hexachlorobenzene (HCB), a persistent and mobile organochlorine pesticide, occurs in environment. HCB has been shown to be present in human follicular fluid. An objective of the present report, which is part of a comprehensive study on reproductive toxicity of HCB, was to determine the cytologic effects of the compound on ovarian follicles in a primate model.Materials and Methods. Eight Cynomolgus monkeys were housed under controlled conditions at Animal facility of Health and Welfare, Ottawa. Animals were orally administered gelatin capsules containing HCB mixed with glucose in daily dosages of 0.0 or 10 mg/kg b.w. for 90 days; the former was the control group. On the menstrual period following completion of dosing, the monkeys underwent an induction cycle of superovulation. At necropsy, one-half of an ovary from each animal was diced into ca. 2- to 3-mm cubed specimens that were fixed by immersion in 2.5% glutaraldehyde in 0.1 M cacodylate buffer (pH 7.3). Subsequent procedures followed to obtain thin sections that were examined in a Hitachi H-7000 electron microscope have been described earlier.


Author(s):  
D. L. Rohr ◽  
S. S. Hecker

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.


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