Ecophysiology - Science topic

Please check the following useful links.

Dear Sir,

See next link:

Good luck,

Hello Jahangir; You will want to see this paper.

Riddell, et al. 2021. Exposure to climate change drives stability or collapse of desert mammal and bird communities. Science 371(6529); 553, 633-635.

It makes comparisons over a 100 year span of time in the Mojave Desert in California. Thermoregulation!

Best regards, Jim Des Lauriers

Shrub: less than 6 meter height with woody stem

Undershrub: Less than 2 m height with woody stem

Also I would like download link, please!

I think the approaches you are looking for could be related to tree architecture studies. So you might be interested in Christophe Drénou's work on the health aspect of trees. The limitation of the method in your case is that it is mostly used in a forestry context on mature trees.

In french:

In english (study case on Quercus robur):

Andrew Paul McKenzie Pegman Thanks for the reply. Is there any software to do so?

Nice effort

Ecophysiology of Plants is the study of plant processes under the influence of different and particular ecological factors: aridity, salinity, arctic, desertic etc.. However, in many situations, there is no clear delineation between these factors: salinity and aridity are connected in many situations, and - sometimes - flooding conditions may be added.

It is about functional adaptations in plants under different conditions of living.

The relative absence of vegetation in the Sahara is partly due to overgrazing by domestic animals. Have a look at the satellite view of Sidi Toui National Park, Tunisia:

This part of the Sahara is surrounded by a fence, and no domestic animals are let in (but the endemic ungulate Scimitar Oryx is living and grazing here). This part of the Sahara is an arid grassland, scattered with some trees:

Cheers,

Lajos

Take a look at recent publication

and associated code using R package rjags

Pretty simple set of implementations in a hierarchal Bayesian scheme for fitting multiple curves at once.

Modifying these codes based on updates such as Moualeu-Ngangue et al 2016 would be reasonable.

The next Xylem International meeting will most likely be organized by the University of Padova in Italy i September/October 2019. We are finalizing the organisation right now and I will let you know when I know more.

And yes, Cavitation will be "la part du lion" in this meeting!

Hervé

It will be wonderful to look at some exceptional traits like relative growth rate , flowering intensity with earliness, time of maturity in terms of earliness or lateness etc..

And if you have any meteorological station near the place or in the region, averaged monthly evaporation/sq metre would be also useful to relate to your measured areas.

Thank you Arvind,

I was not familiar with Frankignoulle & Bouquegneau 1987

Thanks all for wonderful suggestions especially Dmitry Kutcherov. You are right. Research question is important.

In the experiment you can try different behavior of radiation wavelengths in the visible spectrum, the near 760 nm, which absorbs the chlorophyll a.The various radiation can be close to 760 nm, for other types of chlorophyll, except chlorophyll a, like except chlorophyll b, c , and a  little farther to other pigments it contains algae (brown pigments, red, etc).

You can also make multi-variant combinations of several factors : different light intensity, different composition of light, different temperatures, different salinity of water.

You can imagine different matrices, keeping one or more constant and telling others.

Good luck in yous work.

Iuliana

I think you could need a LP-27 Markhart leaf press to extract the liquid sample  directly to a filter paper disc and then  insert the disc into the Wescor C-52 Sample Chamber for the determination of the osmotic potential. That's a secure method that help avoiding some measurement errors. You can see the wescor page in the following link to get the LP.27. And you can see the paper attached as reference. I hope that my answer can be useful. 

It need to study different formation of gas exchange - for exemple,

pore & papillate epidermal cells of Gingko blob and

after the stomatal diversity.

SEE :Robin Y. Smith a,⁎, David R. Greenwood b, James F. Basinger 

Estimating paleoatmospheric pCO2 during the Early Eocene Climatic Optimum from stomatal frequency of Ginkgo, Okanagan Highlands, British Columbia, Canada

There are surely certain  nutrient transporters lying embedded in the plasmalemma of root  cells , the density of which decides the accumulation or exclusion behaviour of roots..

No exploitation of argan oil, only some researchers exploit the oil for phytochemical studies and physicochemical properties

in Morocco the argan tree is protected but Dr Reda Keichairi ask about argan tree of Algeria

link.

If you want to develop full potential Ecophysiology lab you need following infrastucture

1. Water potential measurement system (Wescor is good)

2. Portable photosynthesis system (Li Cor 6400xt is good)

3. Fluorescence monitoring system (Walz machines are Good)

4. Conductivity bridge for assessing membrane damage etc.

5. If you want assess oxidative damage in plants you need a spectrophotometer

6. Portable leaf area meter etc.

7. LAI measurement systems

Good luck for having adequate funds  because all these equipments are bit costly.

Dr. Annamalainathan

Hi,

The question is how to integrate the stoichiometric concepts into the field data recalculations calculation ? Now field hydrobiologist can use coefficients of tempreture dependend functional indices like respiration or production, and amadements on oxygen concentrtation. But how to calculate disbalance or lack???

Andrey

Thank you for your response

Dear Mehdi and Juan Antonio,

Yes, indeed a 1 m bar-type quantum sensor would be the best instrument for measuring PAR in a canopy. Using a small sensor is not impossible, but would require many replicate measurements (in the order of hundreds per location).

What is usually the difference between expensive and cheap quantum sensors?

1) Spectral response: Li-Cor is best with this, you can use Li-Cor sensors under different white light sources with the same calibration and relatively small systematic errors: say less than 10% or so. Cheaper sensors are not really true PAR sensors, they are calibrated as PAR sensors but tend to need recalibration for each different light source. Even some of Apogee's sensors suffer from this problem http://www.apogeeinstruments.co.uk/quantum/ and while Apogee is outspoken about it, other cheap sensors for which makers do not publish the spectral response may be even worse in this respect. For the Spectrum Technology's sensors you can find in their website a manual where the spectral response is plotted, if you compare this curve to that for the "original Apogee" sensor and the true PAR response one can see that the spectral response of this cheaper sensor is really not at all like PAR. However, if the spectral quality of the light is known and the calibration has been done for this same spectral quality, measurements can be almost as good, but you need to take into account that the calibration is strongly light-source dependent. In any case I would not buy any light sensor unless the manufacturer publishes the sensor's spectral response curve as part of the specifications.

2) Cosine correction. Usually only the most expensive sensors get close to the theoretical response as the angle of incidence of light changes. This is especially important, for a horizontal sensor, when solar angles are low, or in any other situation when light is received at a low angle, possibly under a bush in a discontinuous canopy. Again I would not buy any sensor unless the manufacturer specifies the cosine-correction errors.

Other considerations:

a) Buy a sensor that is attached to the meter with a long cable, otherwise you will be unable to avoid your own shade affecting the measurements. Even with a long (2-3 metres) cable make sure to be as low as possible (not standing) and blocking as little of the light as possible. Be also aware that if wearing white or light-coloured clothes you can also increase the readings by acting as a reflector if suitably positioned. The best way to work out what is safe is to rehearse and experiment.

b) For measurements to be reliable and comparable, the sensor needs to be levelled. Li-Cor, Apogee, and most other makers of sensors for field use sell levelling bases with a spirit level. These bases do also play another role: they are heavy enough to keep the sensor where you want while you move some distance away from it to take the readings without causing shading.

c) Temperature stability should be o.k. for most quantum sensors. Weather/water proofing will vary.

Additional thoughts:

1) With care, if you can borrow one of the expensive sensors or a good spectrometer you can calibrate a cheap or even a home-made sensor. This may make sense if you need many sensors.

2) Any sensor should be recalibrated regularly. Calibration of cheap sensors may drift more, requiring more frequent recalibration under continuous field use. Li-Cor sensors are very stable in my experience: recommendation is to recalibrate at least every two years. For Li-Cor sensors this really holds even for continuous measurements in harsh climates. I have no experience with other makes.

3) In addition be aware that the absolute values, and the ratio between above and below canopy irradiance will depend on solar elevation, as well as on how diffuse daylight is. This last point means that measurements on cloudy and sunny conditions, even if expressed as a ratio will not be comparable.

After writing all this, I need to add that in my experience the two most important sources of errors in this type of measurements are: using "subjective" sampling (not well designed protocol for deciding at which points under the canopy to take readings in an objective way), insufficient replication to account for the high spatial heterogeneity and shading (most frequently partial shading by the operator).

Pedro.

Dear Uwe & Michal,

for my opinion you both are right, but important is scale and direct surroundings. Look, for ins. the famous Gause experiments. If you have to do with protists it can be very important what say Michal. Both compounds - I mean behavioral (meanwhile, experience) and physiological "compatibility" of prey present in some proportion for the every predator or semi-predator, but for cheetah experience orientate it when it has choice of victims, but if hungry will no possibility to select.

I saw ciliated infusoria from Dileptus (absolute predators!) genera that eat diatoms algae that should be absolutely inappropriate for it? So, may be as well important is the stage of attack on prey and physiological state of both?

If take into consideration hunting plants - like Nepenthes Rajah (e.g.) from Borneo, the pharmacy of an object is of dominated importance!

The very good explanation of how it works in compact manner gives Wolfgang Meyerhof & Sigrun Korsching in preface of perfect book

Chemosensory Systems in Mammals, Fishes, and Insects. © Springer-Verlag Berlin Heidelberg 2009.

And you can read their opinion of the main scientists in the field (12 person)..

Look attached file.

Andrey

I´m using a LICOR equipment for mesasuring conductance and assimilation  but exist a good porometer to get a good conductance measuring. Calibration is essential.

CO2 Consumption and fixation depend upon assimilate sinks, in other words, growth rates, and the actual biomass..... if there is no source depletion the fixation is inhibited..... this in general, fixation of CO2 is also dependent on light, water, and temperatures, which affect Rubisco directly owing to cellular membrane fluidity...  

C4 plants adopted varying CO2 fixation methods, such methods enable C4 plants like sorghum corn, sugar cane and other grasses to fix CO2 concentration at mesophyll close 1 ppm... in other words it can sustain photosynthesis from 330 ppm to 1ppm which takes longer times than C3 which ceases it photosynthesis from 330 ppm dawn to 100 to 70 ppm depends upon varieties. this mean that C4 can continues photosynthesis when their stomata are closed till evening, not like C3 which approaches the compensation point  for a wile after closure ... at evening ..... Drought resistance mechanism.....

Dear all,

I would like to mention toxicity of pollen which plays a major role for oligolectic bees; see for example: Praz C.J., Müller A., Dorn S. (2008) Specialized bees fail to develop on non-host pollen: Do plants chemically protect their pollen? Ecology 89, 795–

804.

Klaus

Dear colleagues, thank you for your valuable answers.

I thank you very much for your answers. What about the molecular analysis?

Polyethylene glycol molecules with a molecular weight

larger than 6,000 (PEG 6000) are inert, non-ionic and cell impermeable.

They are small enough to influence the osmotic

pressure, but large enough unabsorbed by plants. Therefore, they are frequently used

to simulate osmotic stress.

Dear Andrey,

thank you for your reply. Can you please send me a copy of your paper ?

I will then talk to our statistics cracks in the institute.

Best wishes

Andreas

The most visible effect of AMF was observed in Coffee, even in areas where the soil is deficit in P and other key nutrients. Enjoy the attached review, though few years old.

Gracias Miquel, esta base de datos se ve muy completa. Voy a ver si me informo del procedimiento para hacerme miembro de TRY.

Un saludo

If you take multiple images of your area of interest you could use the Structure-from -Motion approach to model the veg in 3D (similar to the link Anupam posted). Just be aware that if you rely solely on the onboard GPS for georeferencing your error bars could be rather large. Two open source SfM softwares are:

I want ot observe all components of behavior, but primary swimming and coactions with the parasites.

Thanks to everyone who answered on the question and happy New Year!

It depends what do you know. I had made measurements of gas interchange (with a Li-6400) in mangrove and banana using environmental conditions with good results. However I also made measurements in epiphytic bromeliads in a cloud florest. Here, the problem with 6400 was the high humidy (above 80% all day) which made the stabilization of the equipment slow. But I think that is possible to do good measurements with a gas analyser if you have some patience...

This is actually a pretty old question in thermal biology. Another version of the problem is "why are beetles in the Namib desert black?" Most of the animal physiology textbooks should give substantial insight as a starting point. Withers (1992) "Comparative Animal Physiology" is my usual starting point.

Anyway, the crux of the thing is that black is a pretty good colour in both cold and hot environments, depending on the aim of the game. In the cold it's a very good colour for absorbing heat (hence basking in ectotherms is often facilitated by physiological darkening). The thing is, through, in hot conditions it's a very good colour to dump excess heat. Since black surfaces become so much warmer than the environment heat can easily transfer from the surface by convection or conduction. So the real question you're asking here is what's the evolutionary driver for the vultures in these hot environments? Are they aiming to absorb and retain heat, or are they aiming to dump it? And of course this depends on their altitude, because during high altitude soaring they probably want to retain heat, but at low altitude they probably want to dump it. Hence, for a vulture, black is probably the best colour they could be because they can play both ends off against the middle.

This is, of course, all my general speculation. If you read some general textbooks you should be able to see whether my broad understanding is correct. Also, if you read the paper attached by Dr Blount (and references therein) you'll get a more detailed understanding specific to birds, and of course the whole thing is flexible to the stressors of ecology and evolution, as suggested by Dr. Veroustraete. My caution here is that even a simple question like this often indicates complicated patterns, and that if you get trapped in to narrow a set of assumptions, such as "black is a good colour for cold environments" you can often miss powerful insights.

Anyway, I hope that helps. I've suddenly realised that this reads like a lecture, and I'm probably not qualified to give one. Cheers

Sean

Hi Glenn,

A new online journal entitled Conservation Physiology was launched,last year. I suggest to check it out for ideas. We published an invited review in the very first issue of the journal, in which we explore some ideas relevant to your question. It's available here on RG.

Regards,

Hans

Dear Haitao

you might refer in a first instance to the back diffusion of 18O enriched water from the sites of evaporation to the mesophyll itself, which is described by the Péclet effect (radial and longitudinal as described by Farquhar and Gan 2003). If I understand you correctly your point is that this back diffusion could or should also occur from one leaf to another. What we do know is that the water in the phloem sap is 18O enriched compared to the xylem (e.g. Gessler, A., Peuke, A. D., Keitel, C., & Farquhar, G. D. (2007). Oxygen isotope enrichment of organic matter in Ricinus communis during the diel course and as affected by assimilate transport. The New Phytologist, 174(3), 600–613. doi:10.1111/j.1469-8137.2007.02007.x - Fig 4 c; and also some papers of Lukas Cernusak). We also know that newly developing leaves (which do not transpire, yet) are supplied with C via the phloem and thus via the mass flow in the sieve tubes (slightly) enriched water might be transferred to such leaves. This would however be symplastic (phloem) transport and not apoplastic transport and only from transpiring to non-transpiring leaves. Apoplastic diffusion through the petiole and the twig would need to occur against the advective flow in acropetal direction over a real long distance (compared to the back diffusion in the leaf lamina). So I would guess that it is not very likely for mesophyll water of the upper canopy to have a measurable impact on leaves of the lower canopy. What do you think?

Cheers

Arthur

Thanks for posting this Neil. Interesting paper. I'd be interested to know your, and others, views on the severely non-normal distributions of the telomere lengths of different individuals. To me this looks like a small cluster of uncorrelated data, with various outliers dotted around that must completely drive the regressions and estimates of significance, particularly since they used Pearson rather than Spearman correlations. Given the distributions - rank correlations would seem much more appropriate. My guess is that if they had ditched the three outliers with very high RBC telomere lengths instead of just one, all the cross tissue correlations would disappear.

The ratio Ames/A (mesophyll deconvulted area/ projected leaf area) has been the subject of some issue about gas exchange efficiency. Both PS Nobel and D Parkhurst related this ratio to mesophyll resistance. As the measure of Ames is time consuming and includes stereology and approximations it is advisable to search adaptations within a species by specific leaf area variations. Your question takes a very simple character instead, like the relative lenght of two leaf compartments in trasverse section., but there are behind light density adaptations far more effective than water stress on this ratio. I would well check the mean leaf area in the case, if for example the more spongy ones have larger leaf areas. If cell wall is the thickess is the same the effects could be due to bulk elstic modulus as in Plant Cell Physiol. 2006 Jun;47(6):715-25. Epub 2006 Mar 29.

The bulk elastic modulus and the reversible properties of cell walls in developing Quercus leaves.

Saito T, et alii

but you should better define the relationship in terms of absolute potential and turgor potential after a Pessure Volume Curve and ...

Vessels and fibers in most cases easely be differentiated by cell wall thickness and by the ratio between cell wall and lumen. Also differentate stainig can be used for such search. Also the location of elemets is very important for differetiation of such tissues. It will depend on what plant you study. I think, that you can find more helpful information in 3rd edition of Esau's Anatomy or in similar literature.

Dear Ruzhen Wang,

I worked in the Institute of Applied Ecology during 2004-5. I can tell you clear answer, about 10-35 percent carbon is released in the soil through Root exudate, but, nutrient foraging by fine roots for N and P not for carbon. Once a fine root played the role for nutrient foraging then that fine root will die. Therefore, dead fine roots are good source of nutrient as well as carbon for saprotrophs. It is matter of species specific, how much quantity of fine roots biomass producing with respect to life span of a plant. Ideally, photosynthetic output is significantly responsible for fine root production, but if a plant is living in a limited and stressful environment and in addition nutrients (N and P) are limited, in that condition, plant may produce more fine roots stead of structural component like coarse root and stem.

In brief, carbon sequestration in below ground system is not clearly understood, so far I can not say with evidence.

Hi,

You don't actually need to use imaging techniques to measure mt density... One of the easiest way is to measure the citrate synthase with a spec. See this publication: http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2012.230185/full.

Hi Andrew, i currently trying to, in part answer, the same question, I writing a chapter for a book on climate change and aquaculture on coastal carbon stocks. So here is my take on the question. First in general, if you dont have it already, the book ocean acidification by Gattuso and Hansson, is a good andlatest general read on those aspects. More specifically your answer by my standpoint has 3 parts, physiological response to a range of independent variable, adaption and the type of adaption that evolutionary fitness criteria imparts. The latter im sure you are familiar with as this was addressed for coccoliths from work down at the MBA in Plymouth. The second, is about the genome variability and the time and possible adaption for selection that meets the ecosystems criteria for success, what ever that may be. The time for selection is mixed for chlamydomonas after 1000 s of generations in a lab experiment found nothing. However, to be fair it needs a population that has been subject to large variations in pH etc. for example upwelling regions. If you have info on this over the longterm, i would be grateful. The first, is the nature of the concentrating mechanism, whether it requires an external proton transferred into the cell producing calcium carbonate outside and extra pCO2 inside or the bicarbonate converted through the usual carbonic anhydrase. Either way, with lower pH comes higher pCO2 and if the light is sufficient, in which it may be lower from increased cloud cover, there is a excess of fixed carbon over nitrogen over its Redfield optimum. Or the lower supply of nitrogen from increased stratification will also produce or add to a highe carbon to nitrogen ratio. In other words autotrophs are plastic in their stochiometry but not consumers. Consequently, and in this way i m using stochiometric theory to predict that higher CN ratios will lead to more detrital proportions and lower consumer production. See Hessen et al reviews on this 2004, a series in Ecology 2004 on sequestration and stochiometry and Hessen and Andersen, 2008 in L&O.

This is what I have gathered for myself so far, if you have any info on upwelling acidification and changes over time on sequestration, i would be very grateful

thanks a lot, I have not been aware of two of these suggested papers.

After the death of birds occurring natural changes of normal parameters. You want to collect blood serum?

Hi-How far is your water table? actually my response is like a comment than an answer. we have had Institu sensors Aquatrolls 100 measuring salinity in real time of groundwater. Soil salinity is hard to measure continuously. We made a slurry and measured soil salinity in the lab, the thing is there is little water in vadose zone and most sensors measure conductivity of a solution so one has to dilute soil solution and then revert it back to get the native salinity values. Do let me know if you are successful in this quest.

@ Ahmad

thanks for your commends, we trying to study the three tee growing regions this came under three grids and three different geographic locations. we tring to project the same in spatial models in the we should know the coefficient values that will be used in projection models. I understand the the risk of site specific models however statistical downscalling will help to creat a region specific model upto 24km.

If possible i wll try to get Mr. Kurukulasuriya, in this regards

Hi Senadheera,

first of all, thank you very much for your interesting and your offer of help.

The idea of this topic was to understand if some models similar to what I have in mind alredy exist. In case of positive answer, I could try to persuade my tutors to open this parallel topic, contrarily I've no time in this period to start to build a new branch of the current model.

However,

thanks anyway

Hi Robert,

Thanks a lot. Baldocchi's notes helped.

From the look of the signal, it should be easy to approach this problem in any of several different ways. You could load the file into any data analysis environment, detect spikes above a threshold value, time the interval between spikes, and write mean values to a separate data vector or text file. Automating this process is straightforward in almost any advanced data analysis environment. Or you could go the analog route. You can trigger a monostable multivibrator from the spikes, and then integrate the output of the multivibrator using a low pass filter to create an analog voltage proportional to the frequency of the spikes. You can then record that analog voltage with any data acquisition system.

Speaking particularly to herbivore diet from fecal samples -- phytolith analysis has much to offer. I have looked at far more human paleofeces than herbivore feces, but the principles are the same. For any paleofecal analysis we consider a suite of samples. Pollen, phytolith, and starch analyses comprise a set of microscopic analyses that have been very productive. Each contributes the potential to address different portions of the diet. Pollen and phytoliths are not destroyed in the mouth or anywhere else along the digestive tract. In fact, they are very well preserved in paleofeces. Starches should start their process of digestion in the mouth, so recovering starches can be more problematic. Parasite eggs can be found along with pollen using the appropriate extraction method. Macrofloral analysis also is quite valuable since seeds tend to be very well preserved after traveling through the digestive tract. Some plant cells are preserved, while others simply contribute to the background of unidentifiable remains. I examined paleofeces from Nubia for pollen, phytoliths, parasite eggs (none found in that study -- although I've recovered them in other samples), macrofloral remains, and faunal (animal bone) remains for my dissertation (Cummings, Linda Scott 1989 Coprolites from Medieval Christian Nubia: An Interpretation of Diet and Nutritional Stress. Ph.D. dissertation, Department of Anthropology, University of Colorado, Boulder, Colorado.)