This document discusses the effects of water stress on plants. It notes that both water deficiency and excess can injure plants, with symptoms including wilted leaves, reduced growth, and discolored or necrotic foliage. Short-term water deficit may cause minor wilting while chronic deficit results in more severe impacts like stunted growth. Excess water can also stress plants by reducing oxygen to roots, potentially leading to root damage and disease issues. The document provides recommendations for managing water stress through crop selection and irrigation timing.

1. EFFECT ON PLANTS

2. ZOHAIB UL HASSAN
email: zuhaib1144@gmail.com
PLANT PATHOLOGY
University College of Agriculture ,
University of Sargodha,
Pakistan.

3. Water is an important requirement for growth
and survival of plants.
The plant's physiology and biochemistry are
affected .
Both water deficiency and excess can cause
injury to plants.
. Sometimes the injury is short-lived (acute;
several hours) or long-lived (chronic; days or
weeks).

4. Diagnosis of water status problems can be
difficult.
Symptoms confused with injury from salts or
herbicide etc.
Certain infectious diseases such as root-rot
(e.g., Phytophthora spp.) and vascular wilt (e.g.,
Ophiostoma ulmi) also cause similar symptoms
such as wilting.
A soil test might be necessary .

5. If soil appears to be excessively wet, is
discolored, or smells strongly of rotten eggs,
water drainage in the area should be
addressed.
Plant samples should be collected and sent to
a reputable diagnostic lab for analysis.

6. occur either as a short-term or chronic
deficiency.
SHORT- TERM:
A short-term deficit of water might result in
only minor effects on the plant such as wilted
leaves or shoots .

7. These symptoms may be temporary and
occur during the warmest part of the day
when transpiration rates are highest.
Once the environmental stresses are relieved
the symptoms of low water status may
disappear.

9. CHRONIC PERIOD:
During chronic periods of water deficit, the
injury sustained by plants may be more
severe.
Plants may grow more slowly or not at all.
young leaves may not fully expand.
foliage may not appear as colorful relative to
foliage.
In severe cases "scorching" or marginal leaf
necrosis can occur on deciduous trees.
needle necrosis can occur on conifers.

11. During winter months when rain or snowfall
might be scarce, plant roots may not be able
to absorb water.
The result is winter desiccation, in which the
foliage might appear off-color, "scorched", or
necrotic .

13. Excessive soil moisture can result in reduced
oxygen availability to roots.
primary symptom of flooding is plant wilt.
excess soil moisture can manifest as acute or
chronic.

14. roots are subjected to low oxygen status and
cell weakening and/or death occurs.
Symptoms include discolored and/or water-soaked
and mushy roots.
Way of entry for different pathogens like
Phytophthora spp. , anaerobic and low-oxygen
conditions can be detrimental to
nematode populations.

15. plants appear stunted and have
underdeveloped shoots.
In severe cases bleeding cankers on stems
can occur.
Adventitious roots may form at the root
crown.
Edema or corky, blister-like swelling can
occur on the underside of leaves on plants
growing in waterlogged soils.

16. . Edema can be worse during cloudy, overcast
periods.
In areas where waterlogged soils prevail for
long periods of time, an odor of rotten eggs
may be noticeable, due to sulfur gas
production in the anaerobic soil.

17. How can plant water stress be managed?
Crop selection
plant groups and how they behave under
moisture stress can be used to guide
decisions about crop selection for drought
and saline conditions.

18. Determinate crops
Indeterminate crops
Forages

19. Crop type Water stress limitations Management tips
Table. Crop selection for water stress management.
Determintate crops
Resistant to water stress
during vegetative
stages.
Avoid water stress
during reproductive
stages.
Indeterminate crops
No specific critical
periods.
Sugarbeets are more
stress tolerant than
potatoes, carrots, and
onions.
Forages
Perennial forages are
least affected by
moisture stress in the
long run.
Concentrate irrigation
efforts early in the
season to maximize
production.

20. How can the consequences of plant water
stress be minimized?
Wtaer stress timing
Crop selection

21. Water stress timing
1st choice - Early in the crop growth cycle
2nd choice - Close to harvest

22. Crop selection choices
1st choice - Perennial forages
2nd choice - Annual forages
3rd choice - Short season indeterminate
crops
4th choice - Short season determinate crops
5th choice - Long season determinate crops