DB Salinity.

DB Salinity.

1. Once saline has been established in soil it can no longer be taken out.

   • Areas that are salinized cant have plants growing there anymore thus planing will need to take place elsewhere

2. Different ways salt can be transferred

   • Wind.
     • sea spray can also effect unsalinised coastal areas.
     • Coast areas can be effected due to strong winds transmitting salt.
   • Temperature rising causing melting of ice caps thus results in rise of sea levels
   • Inland soil.
     • Most water that falls are percepitation and if saline groundwater rises and is concentrated at the surfaces this will kill plants and land will be open to erosion.

3. Categories of salinity that can be found.

   • Saline soil.
     • Has high content of soluble salts that often crystalize in the surface forming a white crust
   • Saline Sodic.
     • Soils have high content of soluble salts like saline soil but the salts are just sodium salts and if not treated properly can result in harm for the plants.
     • Sodic salt are mostly alkaline.
     • Sodium salt are predominent

4. Negative effect on plant.

   • Salt causes interferance with water uptake of plants causing dehydration, ion toxicity and interferance with potassium nutrition.
   • Problem.
     • Potassium (K+) is a form of nutrition for plants but a problem is that it is similar to sodium as they are found on periodic table order.
     • Sodium is toxic to plants and potassium is an essential nutrient
   • Nutrient pathway in crops.
     • nutrients must be transported across membranes to enter into the plant "root hair" which requires different pumps and channels to transport potassium sodium, which means that the root hair has pumps and channels.
       • Channels and pumps are sufficient for ions that are needed.
       • Casparian strip.
         • Region in dermus that contains cells that have water-proof walls and acts as a barrier for nutrients to be transported into the cells.
       • Apoplastic pathway.
         • Allows water to be transported in an un-controlled manner once it reaches the casparian space, water will build up and it becomes water proof.
       • Bi-directional pathway.
         • More effective in plants that are living in high sodium and potassium environments, have more selectivity in terms of channels and pumps to allow then to not take up sodium.
           • Pathway currently not in crops so it doesnt help when sodium is also taken up.

5. Strategies towards soil salinasation.

   • Better management strategy i.e. in Australia stripping of land dividing it into uncultivated crops and cultivated crops, and thus the uncultivated sections can be planted with salt resistant trees or plants that are able to go into the soil and obtain ground water.
   • Alternative crops that are able to grow in saline soil, which are edible. An example of this are dicots that are able to grow in interdial salt marshes.
   • Breeding and engineering for salt tolerance, such as tissue tolerance i.e. storing ions in area's of tissue that will not harm the enzymatic reaction of the plants.
     • Osmotic tolerance such as reducing water loss and maintaining growth.
     • Ion exclusion such as ions not taken up from the root of plant due to channels not specific to the metal.
     • Example of this : Gene from weed taken and introduced via agrobacterium into maize undergo mediated transformation under maize ubiquitin promoter. Results showed that the transgene line versus the wild type was more successful.
   • Phenomics is the study of how genetic material of an organism can be determined and this can be done via various methods such as drones, to measure the performance of an entire field of cultivars.