Lecture 1 stress physilogy introductin.pptx

for research studies

1. AGR-607 Stress Physiology 3(2-2) Objective : To elaborate the concept of stress in field crops and approaches to sustain yield under stressful conditions. Theory: Introduction and importance of different stresses in crop production, Temperature, radiation, water, mineral, salts, chemicals and pollutant stresses, Plant behavior and adaptation to different stresses, Modification of plant growth and development patterns under biotic and abiotic stresses, Emphasis on the physiological and biochemical basis of injury and plant resistance mechanisms, Approaches for ameliorating the stress effects for crop production.

2. Practical: Demonstration of different stresses in the field and laboratory, Demonstration of morphological features of crop plants for stress resistance, Mineral toxicity and deficiency symptoms in crop plants, visits to affected areas and noting the patterns of vegetative and reproductive growth of crop plants . Demonstration of drought and salt stress under controlled conditions, data collection , analysis and report writing AGR-607 Stress Physiology 3(2-2)

3. Books Recommended: Arnon , I. 1992 Agriculture in Dry Lands: Principles and Practices. Elsevier Publishers, Amsterdam. Mahalingam , R. 2014. Combined Stresses in Plants: Physiological, Molecular, and Biochemical Aspects. Springer. Nosberger , J.H. H. Geiger and P.C. Struik . 2001. Crop Science Progress and Prospects. CABI Pub., Oxford, UK. Pessaraskli , M. A. 2000. A. Hand Book of Stress Physiology, Marker and Deekar . USA Taize , L. and E., Zeiger . 2010. Plant Physiology 5th Ed. Sinauers Associate, Inc. Sunderland Massachusetts, USA Turner, N.C. and P.J. Kramer. 1980. Adaptation of plants to water and high temperature stress. William G. Hopkins and Norman P. A. Huner . 2009. Introduction to Plant Physiology. 4th edition. John Wiley & Sons, Seva Nayak Dheeravathu , Vikas Chandra Tyagi , Chandan Kumar Gupta, Edna Antony. (2017), Manual on Plant Stress Physiology. ICAR-Indian Grassland and Fodder Research Institute, Jhansi. Praduman Yadav, Sunil Kumar, Veena Jain. 2016. Recent advances in plant stress physiology. Daya Publishing House, India. Shankernand A., K and B. Venkateswarlu . 2011. Abiotic Stress in Plants – Mechanisms and Adaptations, Edited by InTech Janeza Trdine 9, 51000 Rijeka, Croatia. www.intechopen.com AGR-607 Stress Physiology 3(2-2)

4. Marcel Jansen, University College Cork, Ireland

5. Marcel Jansen, University College Cork, Ireland

6. Marcel Jansen, University College Cork, Ireland

7. What is stress ? In Physical science: Any force or stimuli which change dimensions of an object. With relation to plants Any change in environmental conditions that adversely effects normal functioning of plant (growth and development) Strain ?. In Physical Science The change in object’s dimension in response to stress. Biological strain with relation to plants The reduced or changed function of the plant in response to stress .

8. Types of Biological strains Elastic biological strain Those changes in plant’s function that return to optimum level when environmental conditions are again normal (i.e. when stress is removed). Example: Reduced photosynthesis in response to low light which returns to normal rate with normal intensity of light. 2. Plastic biological strain. Strain which bring irreversible changes in plants. For example, changes caused by stress of water deficit and drought, frost, heat, salinity etc. If the stress is moderate and short term, the injury may be temporary and the plant may recover when the stress is removed. If the stress is severe enough, it may prevent flowering, seed formation, and induce senescence that leads to plant death. Such plants are considered to be susceptible .

9. Types o f S tress Biotic stress ◇ pathogen stress Abiotic stress ◇ chilling stress ◇ freezing stress ◇ heat stress ◇ wet stress ◇ flood stress ◇ drought stress ◇ salt stress/salinity ◇ Shade stress ◇ Excess light stress ◇ UV/infra red light ◇ Nutrient deficiency ◇ Nutrient toxicity ◇ Anoxia/hypoxia (oxygen stress) ◇ CO2 stress (deficiency/excess) ◇ Air pollution Etc. temperatures stress water stress light stress nutrient stress

10. TYPES OF STRESS FACED BY PLANTS Abiotic stresses 2) Biotic Stresses Abiotic stress Chilling stress, freezing stress, heat stress, wet stress, flood stress, drought stress, salt stress, Shade stress, Excess light stress, UV/infra-red light, Nutrient deficiency, Nutrient toxicity, Anoxia/hypoxia (oxygen stress), CO 2 stress (deficiency/excess), Air pollution, etc. Biotic Stresses B acteria , fungi and viruses and herbivorous animals.

11. Plant Stress Physiology? The study of processes and functioning of plants under stress or adverse environmental conditions is called stress physiology. Stress Physiology is an important branch of Environmental Physiology or Ecologi cal Physiology . Interaction of stress factors In many cases the abiotic stresses do not occur independently. For example, (Acid stress vs. Al toxicity): If Aluminum (Al) is abundant in soils, then under acidic conditions (pH 5.5) Al is solubilized to levels that inhibit plant growth. under water deficits stress, evaporation is reduced which results in: stomata closure, reduced cooling of plants and heat loss. It results in reduced carbon dioxide fixation, and hence reduced growth . Thus plants experienced more injury

12. FACTORS AFFECTING STRESS RESISTANCE IN PLANTS

13. • Resistance includes adaptation, avoidance and tolerance or escape • Adaptation is permanent resistance to stress in morphology and structure , physiology and biochemistry under long-term stress condition. • Avoidance is a manner to avoid facing with stress using neither metabolic process nor energy. Very short lifecycle in desert plants. Dormancy during the cool, hot, and drought conditions. • Tolerance is a resistant reaction to reduce or repair injury with morphology , structure, physiology, biochemistry or molecular biology, when plant counters with stress. • Hardening is a gradual adaptation to stress when the plant is located in the stress condition. What is stress escape?????

14. Marcel Jansen, University College Cork, Ireland

15. If tolerance of a plant increases as a result of exposure to prior stress, the plant is said to be hardened or acclimated . The adoption usually refers to “ genetically determined level of resistance acquired by plant through a process of selection over several generations ”. Hardening or Acclimation vs. Adoption