Hello,

The best experimental system to study differents problems of plant growht in salt stressed media is an hydroponic culture to avoid the effect of indesirable factors.

Hi,

If you want to avoid the effect of soil, the best way is hydroponic solution where you can add salts, studing individually the effects of your treatment.

Even if you are studing salt stress in plants related with drought, you can impose water stress using osmolytes which retain water, like Polyethylene glycol (e.g. PEG-8000).

You can assess the EC or ECe of the soil medium proposed to be used. When adding salt you can reduce accordingly the quantity.

You also need to maintain a control so that the relative performance can be possible

Thanks to all for your help

If you mean by "the effect of the ground", the effect of salts in the soil: you can use aerated nutrient solution to carry out your experiment. Use 1/2 or 1/4-strength of one of the available nutrient solutions.

Semi-hydroponic or ms-agar in vitro culture may be helpful too

If you do not want to switch to hydroponics, I would recommend thouroughly mixing and homogenising the potting substrate before filling the pots.

You can use the sand washed (with deionized water) and sterilzed at 200°C as substrate

As mentioed by others friends, in my opinion the hydroponic system is the best method for research about salt stress effect on plants.

In case you absolutely need to grow the plants in pots you can use substrates like perlite or sand. Perlite works pretty well with big pots due to its low specific weight. You would have to fertigate your plants with nutrient solution and, in order to provide fairly constant salt and nutrient concentrations, flush the substrate regularly with water.

As described by other researchers ,the best way is the application of hydroponic systems .However, if it's not possible for you to perform these recomendations ,economically ,you would need to homogenized the pot -soils in terms of their EC as much as applicable .

Hi Samia,

You will find to kind of answers to this question: some people will go in the line of the previous responses (use a soil-less setup, either full hydroponic or soil-less, inert substrates). Other will go right to the opposite direction: you do not want to avoid the sol effect, as the soil will interact with salts in several ways you cannot predict if you avoid the edaphic factor (salt availability to the plant, interaction with other elements in the soil, resistance to soil washing, infiltration capacity....). The only way to "control" the edaphic factor is to take it into account. This means different things depending on the objective of you experiment: if you want to apply your results to a specific place, use a soil similar to that of the area; if you want to apply them to a species, try to use some different soil compositions present in the places were this species occurs, at least a couple of them different enough to have an idea of how much is your result of salt stress affected by the edaphic factor.

Both approaches will give you somewhat different (or really different) results, the first pretending to determine the "pure" effect of salt stress and the second determining more realistic situations, although often being unable to distinguish between modifications of salt stress by the soil (for example, alterations of effective salt concentration) or appearance of collateral factors (for example, salt effects on soil microorganisms that would, in turn, affect the plant, so indirect effects).

It's best to remove the effect of edaphic factor in a study of plant tolerance to salinity, is to use inert substrates such as perlite, pumice stone, river sand or peat in experimental pots. Thus it is possible to detect the effect of salts on plants subject matter.

I recommend you read the following articles that I wrote:

1) Edgar Sánchez-Bernal, Manuel Ortega-Escobar, Victor Gonzalez-Hernandez, Marco Camacho-Escobar and Joshua Kohashi Shibata. Growth of potato plants (Solanum tuberosum L.) cv. Alpha induced by diverse salinity conditions. Interscience 33 (9): 643-650.

@Edgar

I would agree with you if you were trying to demonstrate that salinity has an effect on plants (which has already being demonstrated). But if the objective is to show how much salinity affects plants, putting soil apart would have two consequences:

1. You will only see direct effects

2. The magnitude of the effect will not be translatable to any "real" situation in a "real" soil or, for the same purpose, any substrate other than the one used in the assay because of the probable soil interaction with the salts you use, that will change the effective salt concentration.

I agree that this information would still be valuable in many circumstances (for instance, comparing the sensitivity of two species or cultivars, or the interference of another variable in salt sensitivity), But for other objectives, the information will be short.

This is all I meant: pay attention to the objectives of the work before deciding to eliminate soil contribution.

In other words, controlling a variable does not necessary mean to keep it constant or to take it out of the equation, which would also eliminate its interactions with other variables in the experiment, making the results strictly valid only for the precise value the variable had in the experiment.

hello

thank you for these great tips. the test of salt stress in vitro has been the subject of my research. I got good results. for hydroponics test,  it is currently being studied. but the saline test in soilless culture allows me to compare my results. for that, I must find a way to contôler the effect of soil environment to better define salt concentrations tested.

I've been working on salinity stress in vitro but Should be tested on the ground to understand the real impact. So I recommend this method. You can use the sand washed (with deionized water) and sterilzed at 200°C as substrate

Dear Samia,

You should check your real objectives to decide. I totally agree with the complete response of Xavier Aranda.

Be lucky

I am also totally agree with the complete response of Xavier Aranda.

aero-Hydroponic systems are the best appropriated for such kind of experiments. Indeeds, these allow the control of salt dose and avoid dose increase due to repetitive irregation in others systems lik sand, perlite or vermiculite,

Hi Samia,

I totally agree with Xavier Aranda, too.

And I would add: Is your soil already saline? If not you can salinize a non saline soil, so you have the control soil and the saline soil (with different electrical condictivities). And this way you can study the effect of increasing EC in the soil.

If you want the methodology for that let me know.

Barbara

The better way is usage of perlit or vermicolate as culture medium.

Please consider the previous suggestions; and search for my work on 'Drought Tolerance of Maize'.

All former points are fine. But one point is that we are always faced with the real conditions in the field and the goal is to produce food. I may suggest that two treatment may be done. first is to grow the model crop such as potatoes with the non-saline condition in a soil of interest and the other one is to grow the crop in the same soil but add the desired saline water. The differences between the two treatments on any trait that is studied will show the salinity effect. However, I always suggest the hypothesis in real conditions.

I agree with Seyed Hamid Ahmadi sugestion to go with two sets,one non saline and the other saline condition.For the purpose sand culture method can be used.

I completely agree with Hakimeh Mansouri... It is a good way to use perlite as growing medium to see the effects of salt, and meanwhile control the LF (leaching fraction - ratio of drainage volume to irrigation water or nutrient solution volume) precisely. Second is very important and little bit complex in application. Yhe best way is to online measurement of drainage and irrigation with sensors.

You may also check Maloupa et al, 1992...

I totally agree with Xavier Aranda...