2. sorbitol
• Sorbitol, less commonly known as glucitol,
is a sugar alcohol with a sweet taste which
the human body metabolizes slowly. It can
be obtained by reduction of glucose, which
changes the aldehyde group to a hydroxyl
group.
4. Function of sorbitol
• Sorbitol, a six carbon sugar alcohol, is
one of the most frequently found polyols in
plants. It is a direct product of
photosynthesis in mature leaves, in
parallel with sucrose, and both serve
similar functions, such as translocation of
carbon skeletons and energy between
sources and sink organs.
5. Effects of sorbitol
• Common Side Effects.
• Sorbitol accumulation, the adverse
effect of sorbitol could be caused by a
disturbance of the Glucose-6-P pool.
By sorbitol-6-phosphate dehydrogenase,
which might then affect either UDP-
Glucose or Glucose amounts, leading to
altered sugar sensing in the plants.
6. Salt tolerance
• The salt tolerance of a plant is
often defined as the degree to which the
plant can withstand, without significant
adverse effects, moderate or high
concentrations of salt in water on its
leaves or in the soil within reach of its
roots.
7.
8. Soil salinity
• Soil salinity is the salt content in the soil;
the process of increasing the salt content
is known as salinization. Salts occur
naturally within soils and
water. Salination can be caused by
natural processes such as mineral
weathering or by the gradual withdrawal of
an ocean.
9. Acidic and alkaline saline soil
• The pH scale indicates acidity or
alkalinity. A soil with a pH number below 7
is acid, while one with a pH above 7 is
alkaline. Garden plants typically grow
best in neutral or slightly acid soil (pH 7
or slightly below then pH7).
10.
11.
12. Effect of salinity
• One of the most
detrimental effects of salinity stress is the
accumulation of Na+
and Cl−
ions in tissues
of plants exposed to soils with high NaCl
concentrations. Entry of both Na+
and
Cl−
into the cells causes severe ion
imbalance and excess uptake
might cause significant physiological dis
order.
13. Effect of salinity
• The Effect of Salinity on Plants. First,
the presence of salt in the soil solution
reduces the ability of the plant to take up
water, and this leads to reductions in the
growth rate. This is referred to as the
osmotic or water-deficit effect of salinity.
15. Effects of salt tolerance
• Salinity stress involves changes in
various physiological and metabolic
processes, depending on severity and
duration of the stress, and ultimately
inhibits crop production . Initially
soil salinity is known to
represses plant growth in the form of
osmotic stress which is then followed by
ion toxicity .
16.
17. Effect of salt on photosynthesis
• Photosynthesis, together with cell
growth, is among the primary processes to
be affected by water or salt stress.
• When compared with drought, salt stress
affected more genes and more intensely,
possibly reflecting the combined effects of
dehydration and osmotic stress in salt-
stressed plants.
18.
19. Control of soil salinity
• Soil salinity control relates to
controlling the problem of soil salinity
and reclaiming salinized agricultural
land.
• The aim of soil salinity control is to prevent
soil degradation by salination and reclaim
already salty (saline) soils.
• The primary man-made cause of
salinization is irrigation.
20. Reclamation of saline soil
• The following techniques or events can
help reclaim saline soils.
• Salt can be leached out of the root zone
through good quality irrigation water or by
heavy rainfall.
• Create good surface and internal
drainage.
• Break the compacted layers that occur
near or at the soil surface.
21. Approaches use for controlling
salt tolerance
• Various approaches have been taken to
improve the salt tolerance by introducing
genes for salt tolerance into adapted
cultivars, including screens of large
international collections, detailed field
trials of selected cultivars, conventional
breeding methods, and unconventional
crosses with wheat relatives.
22. • The aim has been to exploit variation in
salt tolerance within wheat and its
progenitors or close relatives to produce
new wheats with more tolerance than
modern wheat cultivars.
