1. Plant Stress Plant stress is defined as any change in environmental conditions that produce a less than ideal plant response.  Biotic  Abiotic

2. Biotic Factors microorganisms (bacteria and fungal) virus parasitic plants insects

3. Abiotic Factors Water Temperature Light Soil Nutrients …

4. Water Drought – lack of water Excess – flood situation creating an anaerobic environment where roots are unable to respire due to lack of available oxygen.  Plant/water relations are influenced by atmospheric conditions (evapotranspiration) and will influence drought, cold, and salt stress.

5. TemperatureLight Extremely high temperatures Extremely low temperatures Extreme temperature changes. Photosynthesis Accumulation of certain Pigments  responsible for preventing photo- oxidation from UV light.

6. Soil Salt Stress:  For most plants, the presence of high salt concentrations in the soil is an important stress factor. Sodium chloride (NaCl):  is ambiguously found in nature  deserts, coastal areas.  Irrigation water contains dissolved salts that are conc. as the water evaporates and builds up in soils over time.

7. MacroelementsMicroelements ElementSymbolElementSymbol NitrogenNChlorineCl PhosphorousPIronFe PotassiumKBoronB ManganeseMn CalciumCaZincZn MagnesiumMgCopperCu SulfurSMolybdenumMb NickelNi Nutrient Deficiency A lack of one or more essential elements needed by plants for optimum growth lead to plant stress.

8. Other Factors Chemical Injury Mechanical Injury Transplant Shock. Chemical Injury Mechanical Injury Transplant Shock.

10. High temperature Stress

11. Phosphorus deficiency

12. SULFUR DEFICIENCY

13. NITROGEN DEFICIENCY

15. Objectives Go around campus and record 3 plants that show stress symptoms.  Use a digital camera to take pictures (optional)  Where was the plant located at?  Identify the plant.  What are some of the symptoms you see?  What is the possible cause for each symptom?