i read a lot of publication about about the effect of fertilisation (calcium, humic substances..nitrates..) in ameliorating salt stress tolenrence in plant..But all these research concluded that fertilisation can ameliorate the general status of the plant such as water balances, osmotic adjustment.. soil proprieties..but there are no specific research concerning the real mechanism of amelioration..why mineral or organic fertilisation can ameliorate salt tolerence?
It is the first time that i hear that fertilization can ameliorate the plant response to salt stress by particular mechanisms, although it depends by the specific amounts of macro- and micronutrients, I mean. I think that fertilization can basically mitigate the salt stress because an optimum nutritional status can help the plant to counteract the impairments (NaCl toxicity and osmotic shock) from excess of salt.
Best regards,
In general balance fertilization causes nutrient balance in plants then increase in plant growth and plant tolerance to different stress like salinity stress it means ameliorate salt stress,but high doses of urea fertilizer may have negative effect due to its high solubility .
Under saline conditions, applying N and P fertilizers at the end of the grain filling stage improved yield and metabolic performance of the plants compared to other fertilizer treatments. You can read:
Interaction of salinity, nitrogen, and phosphorus fertilization on wheat
M. S. Soliman , H. G. Shalabi & W. F. Campbell http://dx.doi.org/10.1080/01904169409364796
Other strategies which plants can be enabled to grow on saline soils. The first strategy is to prime seeds before planting by treating them with inorganic or organic chemicals and/or with high or low temperatures. The second strategy involves exogenous application of organic chemicals, such as glycine betaine, proline, or plant growth regulators, or inorganic chemicals to plants under salinity stress. Considerable improvements in growth and yield have been reported in a number of crops using these approaches. Gamma irradiation with growth regulator or other treatments can improve plant tolerance, my publication on research gate include some articles about this subject .
I think, fertilization may help in activation of some enzyme or blocked others.
Fertilization including Ca or K will mitigated the adverse effects of salt stress and enhances salt tolerance. Calcium increasing the selectivity of K over Na, and K/Na ratio is a key trait in salt tolerance mechanism. Calcium is known to increase salt tolerance early since the publication of Epstein in late sixty of the last century. Similarly, supplementation of K affects this ratio and improve salt tolerance. Also, K is a cofactor for many enzymes in the plant metabolism and thus plays role in salt tolerance mechanism.
Some strategies are proposed for alleviation of salt stress such as developing salt-resistant cultivars, leaching excess soluble salts from upper to lower soil layers and reducing salt by harvesting salt accumulating aerial plant parts which are very difficult and costly. Nowadays, a new scheme for amelioration salt stress is to overcome the irregularities in plant physiological mechanisms by some of the plant growth regulators and nutrients. We investigated the effects of salicylic acid and silicon on plant and seed physiology of mung bean under salt stress. We found that both of salicylic acid and silicon significantly decreased Na and increased K accumulation in root and leaf of treated plants under salt stress. Please find the attached files for more information.
All the Best,
Ramin Lotfi
there are two aspects to consider：osmotic stress and ion toxicity . increasing of fertilisation will have a higer osmotic potential, it will hurt plant .on the other hands, increasing of fertilisation may adjust the proportion of ion uptake, it will alleviate the harmful effect of single salt.