scholarly journals Microclimate predicts frost hardiness of alpine Arabidopsis thaliana populations better than elevation

2019 ◽  
Vol 9 (23) ◽  
pp. 13017-13029 ◽  
Author(s):  
Christian Lampei ◽  
Jörg Wunder ◽  
Thomas Wilhalm ◽  
Karl J. Schmid
Keyword(s):  
Arabidopsis Thaliana ◽  
Frost Hardiness ◽  
Better Than

scholarly journals Microclimate predicts frost-hardiness of alpine Arabidopsis thaliana populations better than altitude because the microclimate effect increases with altitude

2019 ◽  
Author(s):  
Christian Lampei ◽  
Jörg Wunder ◽  
Thomas Wilhalm ◽  
Karl J. Schmid
Keyword(s):  
Arabidopsis Thaliana ◽  
Large Scale ◽  
Frost Damage ◽  
Rate Of Change ◽  
Frost Hardiness ◽  
List Type ◽  
Field Station ◽  
Log Linear ◽  
Alpine Environments ◽  
Collection Sites

AbstractIn mountain regions average temperatures decrease at higher altitudes. In addition, microenvironmental conditions can strongly affect microclimate and may counteract average effects of altitude.We investigated winter frost hardiness of Arabidopsis thaliana accessions originating from 13 sites along altitudinal gradients in the Southern Alps during three winters on an experimental field station on the Swabian Jura and compared levels of frost damage with the observed number of frost days (<1°C) in eight collection sites.We found that frost-hardiness increased with altitude in a log-linear fashion. This is consistent with adaptation to higher frequency of frost conditions, but also indicates a decreasing rate of change in frost hardiness with increasing altitude. Moreover, the number of frost days measured with temperature loggers at the original collection sites correlated much better with frost-hardiness than the altitude of collection sites, suggesting that populations were adapted to their local microclimate. Notably, the variance in frost days across sites increased exponentially with altitude.Together, our results suggest that strong microclimate heterogeneity of high alpine environments may preserve functional genetic diversity in small populations. This challenges the suitability of habitat predictions based on large scale climatic variables (or proxies, such as altitude) for topographically complex areas.

scholarly journals Clinorotation Affects Induction of the Heat Shock Response in Arabidopsis thaliana Seedlings

2020 ◽  
Vol 6 (1) ◽  
pp. 2-9
Author(s):  
Liudmyla Y. Kozeko ◽  
Denis D. Buy ◽  
Yaroslav V. Pirko ◽  
Yaroslav B. Blume ◽  
Elizaveta L. Kordyum
Keyword(s):  
Heat Treatment ◽  
Arabidopsis Thaliana ◽  
Heat Shock ◽  
Seedling Survival ◽  
Transcript Abundance ◽  
Mild Stress ◽  
Plant Tolerance ◽  
Stationary Conditions ◽  
Kinetics Of ◽  
Better Than

AbstractClinorotation used to simulate microgravity effects in ground-based experiments is considered as a mild stress factor for plants. We have assumed that it might influence the plant tolerance to other stressful factors. To test this, Arabidopsis thaliana seedlings were grown on a horizontal clinostat (2 rpm) or under stationary conditions (control), and then were subjected to heat treatment. The kinetics of gene expression of cytosolic HSP70s and HSP90s during exposure to 37°C for 0.5-2 h was examined by RT-qPCR to estimate level of the heat shock reaction. It was shown that clinorotation caused the minor increase in transcript abundance of five AtHSP70s and AtHSP90-1 under normal temperature, as well as a faster onset and enhancement of their induction during heat shock. The heat tolerance was evaluated as a function of seedling survival after exposure to 45°C for 45 min. Seedlings grown under clinorotation were determined to withstand heat treatment better than seedlings grown under stationary conditions. The obtained data support the assumption that clinorotation may provide cross-protection of plants against fluctuations in environmental conditions.

scholarly journals Synthesis and herbicidal activity of aryloxyacetic acid derivatives as HPPD inhibitors

2019 ◽  
Author(s):  
Man-Man Wang ◽  
Hao Huang ◽  
Lei Shu ◽  
Jian-Min Liu ◽  
Jian-Qiu Zhang ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Weed Control ◽  
Inhibitory Activity ◽  
Herbicidal Activity ◽  
Better Than

A series of aryloxyacetic acid derivatives were designed and synthesized as HPPD inhibitors. The preliminary bioassay results indicated that these derivatives displayed promising Arabidopsis thaliana HPPD (AtHPPD) inhibitory activity, such as compound I12 (K i = 0.011 µM) and compound I23 (K i = 0.012 µM), which were similar with commercial HPPD herbicide Mesotrione (K i = 0.013 µM). Furthermore, the newly synthesized compounds showed significant greenhouse herbicidal activities against tested weeds at dosages of 150 g ai/ha. In particular, compound II4 exhibited highly herbicidal activity for pre-emergence treatment, even better than those of Mesotrione. Besides, compound II4 was safe for weed control in maize fields at the rate of 150 g ai/ha. Therefore, compound II4 was identified as the most potent candidate for novel HPPD inhibitor herbicide. Compounds described herein might provide useful ideas in the design and modification of new HPPD inhibiting-based herbicides.

scholarly journals Synthesis and herbicidal activities of aryloxyacetic acid derivatives as HPPD inhibitors

2020 ◽  
Vol 16 ◽  
pp. 233-247 ◽  
Author(s):  
Man-Man Wang ◽  
Hao Huang ◽  
Lei Shu ◽  
Jian-Min Liu ◽  
Jian-Qiu Zhang ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Weed Control ◽  
Herbicidal Activity ◽  
Addition Compound ◽  
Better Than

A series of aryloxyacetic acid derivatives were designed and synthesized as 4-hydoxyphenylpyruvate dioxygenase (HPPD) inhibitors. Preliminary bioassay results reveal that these derivatives are promising Arabidopsis thaliana HPPD (AtHPPD) inhibitors, in particular compounds I12 (K i = 0.011 µM) and I23 (K i = 0.012 µM), which exhibit similar activities to that of mesotrione, a commercial HPPD herbicide (K i = 0.013 µM). Furthermore, the newly synthesized compounds show significant greenhouse herbicidal activities against tested weeds at dosages of 150 g ai/ha. In particular, II4 exhibited high herbicidal activity for pre-emergence treatment that was slightly better than that of mesotrione. In addition, compound II4 was safe for weed control in maize fields at a rate of 150 g ai/ha, and was identified as the most potent candidate for a novel HPPD inhibitor herbicide. The compounds described herein may provide useful guidance for the design of new HPPD inhibiting herbicides and their modification.

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

Localization of immunolabels by electron microscopy and image averaging

1983 ◽  
Vol 41 ◽  
pp. 282-283
Author(s):  
J. Frank ◽  
P.-Y. Sizaret ◽  
A. Verschoor ◽  
J. Lamy
Keyword(s):  
Electron Microscopy ◽  
Single Particle ◽  
Attachment Site ◽  
Uranyl Acetate ◽  
Limulus Polyphemus ◽  
Resolution Limit ◽  
Electron Microscopic ◽  
Image Averaging ◽  
Top View ◽  
Better Than

The accuracy with which the attachment site of immunolabels bound to macromolecules may be localized in electron microscopic images can be considerably improved by using single particle averaging. The example studied in this work showed that the accuracy may be better than the resolution limit imposed by negative staining (∽2nm).The structure used for this demonstration was a halfmolecule of Limulus polyphemus (LP) hemocyanin, consisting of 24 subunits grouped into four hexamers. The top view of this structure was previously studied by image averaging and correspondence analysis. It was found to vary according to the flip or flop position of the molecule, and to the stain imbalance between diagonally opposed hexamers (“rocking effect”). These findings have recently been incorporated into a model of the full 8 × 6 molecule.LP hemocyanin contains eight different polypeptides, and antibodies specific for one, LP II, were used. Uranyl acetate was used as stain. A total of 58 molecule images (29 unlabelled, 29 labelled with antl-LPII Fab) showing the top view were digitized in the microdensitometer with a sampling distance of 50μ corresponding to 6.25nm.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Electron Microscopic Observation of the Longitudinal Organization of Poly (p-Phenylene Terephthalamide) Fibers

1982 ◽  
Vol 40 ◽  
pp. 680-681
Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Microscopic Observation ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Aromatic Polyamides ◽  
Radial Arrangement ◽  
Scanning Electron ◽  
Better Than

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.

A High Angle, Double Tilting Cold Stage for the AEI EM7

1974 ◽  
Vol 32 ◽  
pp. 450-451
Author(s):  
P.R. Swann ◽  
A.E. Lloyd
Keyword(s):  
Habit Plane ◽  
Temperature Control ◽  
Tilt Angle ◽  
Cooling System ◽  
Thermal Drift ◽  
High Angle ◽  
Cold Stage ◽  
High Degree ◽  
Better Than

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.

Thermal Considerations in Lens Regulator Systems

1970 ◽  
Vol 28 ◽  
pp. 358-359
Author(s):  
K.C. Newton
Keyword(s):  
Electron Microscope ◽  
Thermal Effects ◽  
Environmental Control ◽  
Reference Networks ◽  
Better Than

Thermal effects in lens regulator systems have become a major problem with the extension of electron microscope resolution capabilities below 5 Angstrom units. Larger columns with immersion lenses and increased accelerating potentials have made solutions more difficult by increasing the power being handled. Environmental control, component choice, and wiring design provide answers, however. Figure 1 indicates with broken lines where thermal problems develop in regulator systemsExtensive environmental control is required in the sampling and reference networks. In each case, stability better than I ppm/min. is required. Components with thermal coefficients satisfactory for these applications without environmental control are either not available or priced prohibitively.

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