ARS/NET Plant Physiology Syllabus

Unit 1: Cell Organelles and Water Relations

Cell organelles and their physiological functions; Structure and physiological functions of cell wall, cell inclusions. Cell membrane structure and functions. Water: Properties and function of water in cell; Soil and plant water relation: Concept of water potential, Plant and soil water potential and their components, SPAC, method to determine soil and plant water status; Mechanism of water uptake by roots, transport in roots and other tissues; Transpiration: Stomatal and non-stomatal water loss from plants, evaporation and transpiration, energy balance, plant and environmental factors affecting transpiration; Stomata: structure and function, Mechanism of stomatal movement, regulation of stomatal opening and closing by endogenous and environmental cues, antitranspirants. Water use efficiency (WUE): physiological basis, methods of measurement, improvement in WUE. Indices for assessment of drought resistance.

Unit 2: Metabolic Processes and Growth Regulation

Energy and work, free energy and chemical potential, redox reactions and electrochemical potential; Enzyme classification and mechanism of action, factors affecting enzyme action; Gene expression and protein turnover; Photosynthesis: Chloroplast- Structure and function; light reaction-cyclic, non-cyclic, pseudocyclic: Rubisco structure and regulations CO2 diffusion mechanism; Photochemical processes- C3, C4 and CAM photosynthesis, Regulation of photosynthetic enzymes, Ecological aspects of C4 and CAM; Photorespiration- significance and approaches to minimize it in C3 plants; Sucrose, starch and polysaccharide metabolism; Phloem loading and transport of sugars; Source-sink relationship; Carbon isotope discrimination; Respiration: Mitochondria structure and function; Electron transport and ATP synthesis; Glycolysis, Krebs cycle, anaerobic respiration; Growth Respiration, Maintenance respiration, Apparent Respiration, Cyanide resistant respiration and its significance; Lipid metabolism: storage, structural and protective lipids; Secondary metabolites and their significance in the plant.

Unit 3: Crop Productivity and Modelling

Physiology of major cereals, pulses and oilseed crops. Role of crop physiology in agriculture; Growth models describing yield (Duncan/Passioura); Crop growth Analysis: LAI, NAR, CGR, LAD, RGR, SLA, SPW, HI; Canopy photosynthesis - leaf area and net assimilation rates as determining factors; Light interception, light extinction coefficient and canopy architecture; Light interception as a major function of leaf area-index; Biomass and yield relations; Assimilate partitioning; yield and yield structure analysis; Concept of source and sink; factors influencing source and sink size and productivity; Concept of optimum LAI. Environmental factors determining crop growth: Light, temperature and VPD, effect of photoperiod and thermos-period on duration of growth stages; Ideotype concept: selection- indices for improving crop productivity; Concept of Thermal time, heat unit, GDD in growth and development of crops; Analytical techniques and instrumentation in plant physiology.

Unit 4: Abiotic Stress Responses in Plants

Abiotic stresses affecting plant productivity: Drought, water logging, extreme temperature, salinity, high and low light; Drought: Drought characteristic features, Development of water deficits, energy balance concept, transpiration and its regulation -stomatal functions/ responses to VPD. Physiological processes affected by drought; Drought resistance mechanisms: Escape, Dehydration avoidance, Dehydration tolerance; osmotic adjustments and Osmo protectants; Stress proteins- LEA, Dehydrins, etc; stomatal regulation for minimizing water loss; Water use efficiency and Passioura’s model; Physiological and molecular mechanism to improve WUE; high and low temperature: physiological effect on plant, role of lipid membrane in tolerance of extreme temperature, HSPs and their function: high and low light stress: photo oxidation, photo inhibition, mechanism of tolerance, shade avoidance response; Salinity: effect on cellular and whole plant level, tolerance mechanism, SOS pathway; Heavy metal stress: Aluminum and Cadmium toxicity effect on plant and their tolerance mechanism, phytochelatins; Stress and hormones: ABA as signaling molecule, cytokinin as negative signal; Oxidative stress: ROS role and tolerance mechanism.

Unit 5: Plant Growth Regulators and Plant Development

Plant growth regulators: Hormones, endogenous growth substances and synthetic chemicals; Endogenous growth regulating substances other than hormones; Classification, site of synthesis, biosynthetic pathways and metabolism and influence on plant growth and development by auxins, gibberellins, cytokinins, abscisic acid and ethylene; Hormone signal perception, transduction- Receptor components, signal transduction and mechanism of action of Auxin, Gibberellins, Cytokinin, ABS and ethylene: Action of hormones on cellular functions: Auxins-cell elongation, retardation of abscission of plant parts; gibberellins-stem elongation, germination of dormant seeds; cytokinin- cell division, retardation of senescence; Abscisic acid-stomatal closure and induction of drought resistance: ethylene-fruit ripening, acceleration of senescence of leaves; Hormone mutants; Interaction of hormones in the regulation of plant growth and development processes; Physiological and molecular aspects of regulation of growth and differentiation, rooting of cutting, Apical dominance, Flowering; role of hormone in fruit growth and development, Senescence, Abscission, induction and breaking of seed and bud dormancy; improving post-harvest life of fruits Synthetic growth regulators; Practical utility in agriculture and horticulture.

Unit 6: Mineral Nutrition

Importance of mineral nutrition in plant growth; Classification and essentiality criteria; Beneficial elements; factors affecting the nutrient availability; critical nutrient concentration; Mineral nutrient: function, deficiency symptoms/ disorders, toxicity and remedies; General mechanisms: concept of apparent free space and Donnan free space; Mineral nutrient uptake and transport: membrane transport proteins - active transport, Primary and secondary transport- carriers and pumps; LATs and HATs; Short distance transport-pathway from external solution (Apoplasm) to sieve across the root cortical cells, factors contributing to xylem loading; Long-distance transport in xylem and phloem, xylem unloading in leaf cells; Foliar nutrition: Uptake and release of mineral nutrients by foliage; Rhizosphere and root biology in relation to nutrient acquisition, influence of micro-organisms in nutrient acquisition, release and uptake by plant roots; Yield and mineral nutrition concept of nutrient use efficiency; Heavy metal toxicity and concept of phytoremediation; Physiological and molecular mechanism of nutrient use efficiency; Nitrogen metabolism; Inorganic nitrogen species (N2, N03, NH3) and their reduction, protein synthesis;. Sulphate uptake and reduction.

Unit 7: Climate and Climate Change

Climate change: definition, history and evidences: analytical methods to determine long term changes in environment-Tree ring, cellulose, stable carbon isotope discrimination, for hydrological changes; Climate change projections and its impact on crop and ecosystem; The greenhouse gases and global warning; CO2 as an important green-houses gas; Effect of elevated CO2 on plant growth and development; Methane as a greenhouse gas. Prediction on global warming; Effect of high temperature on plant growth and development; High temperature and CO2 interaction on plant growth and productivity; chlorofluorocarbon (CFC)-their impact on ozone layer: ozone hole and alteration in UV-B radiation; Technologies for climate change studies (FACE, TGT, OTC etc.) Approaches to improve adaptation to changing environment. Effects of UV-B radiation on plant ecosystem, repair and acclimation to UV-B damage; Carotenoids and their role in membrane stabilization; Air pollution, SO2, NO, methane, ozone, peroxyacetyl nitrate and their effect on the ecosystem. Industrial and domestic effluent their effect, on aquatic ecosystem, plant growth and development.

Unit 8: Seed Physiology

Structure of seeds and their storage; Seed development patterns and source of assimilates for seed development; Pathway of movement of assimilates in developing grains of monocots and dicots; Chemical composition of seeds; Storage of carbohydrates, proteins and fats in seeds; Seed germination: Hydration of seeds, Physiological processes, Seed respiration, mitochondrial activity, Mobilization of stored resource in seeds; Chemistry of oxidation of starch, proteins and fats; Utilization of breakdown products by embryonic axis; Control processes in mobilization of stored reserves- Role of embryonic axes; Gibberellin and α- amylase and other hydrolytic activity; Seed maturation phase and desiccation damage- role of LEA proteins; Seed viability; Seed dormancy; Means to overcome seed dormancy; Interaction of Gibberellin and ABA in regulation of seed germination and dormancy.

Unit 9: Physiology of Flowering and Reproduction

Evolutionary history of flowering plants (angiosperms); Semelparous and iteroparous reproduction; monocarpic and perennial life; Flowering phenomenon; juvenility to flowering transition; Photoperiodic responses and the mechanisms in short and long day plants; Photoperiodism and its importance; Theories related to flowering; Gene expression and control of flowering; Thermoperiodism and its importance; Mechanism of vernalization; Photomorphogenesis, photoreceptors: phytochrome, cryptochrome, phototropins; Circadian rhythms: features and mechanism; Mating strategy in plants, molecular techniques to understand mating patterns, self-incompatibility responses, physiological processes mediating fertilization (pollen-stigma interactions), seed and fruit development, seed and fruit abortion and means to overcome it. Molecular biology of seed development, physiological basis of cytoplasmic male sterility and fertility restoration. Physiology of heterosis.

Unit 10: Physiology of Horticultural and Plantation Crop species

Growth and development of horticultural and plantation crop species; Juvenility, shoot growth, types of shoots, patterns of shoot growth, cambial growth and its regulation; Physiological aspects of pruning and dwarfing; Growth measurements; Water relations of tree species. Water uptake and transport; Sexual and asexual propagation; Rootstock and scion interactions; Physiology of flowering in perennial species, photoperiodism and thermoperiodism; Physiological aspects of fruit crops: mango, banana, grapes, citrus, papaya and pineapple; Physiological aspects of plantation crops: tea, coffee, cardamom, coconut, and black pepper.

Unit 11: Post-Harvest Physiology

Senescence and ageing in plants; Ethylene the senescence hormone; leaf senescence. Monocarpic plant senescence; Biochemistry and molecular biology of flower senescence; Gene expression during senescence; Concept of physiological maturity and harvestable maturity; Post harvest changes in biochemical constituents in field crops: loss of viability, loss of nutritive value: environmental factors influencing post-harvest deterioration of seeds; Physiological and biochemical changes during fruit ripening and storage; Senescence and post-harvest life of cut flowers; Physical, physiological and chemical control of post-harvest deterioration of fruits, vegetables and cut flowers and its significance during storage and transport; The molecular approach in the regulation of fruit ripening; Transgenic technology for improvement of shelf-life; Edible vaccine; Programmed cell death (PCD).

Unit 12: Morphogenesis, Tissue Culture and Plant Transformation

Morphogenesis: the cellular basis of growth and morphogenesis; polarity in tip-growing cells and diffusive growing cells: Control of cell division and differentiation, phytochromes, different forms, physiological effects and gene regulation; cellular totipotency; physiology and biochemistry of differentiation, in organ cell, tissue and cultures; micropropagation strategies; application of tissue culture in agriculture, horticulture, forestry and industry; plant transformation; transformation vectors, concept of selectable and scorable markers; Agrobacterium mediated transformation, binary vectors, biolistics, Electroporation; Selection of putative transgenic plants: genetic analysis, PCR, Southern analysis evaluation of transgenic plants Genetic engineering and genome editing for trait improvement: Introduction to GMOs and its application in crop improvement, Agrobacterium and other methods of plant transformation; Genome editing techniques: CRISPR/Cas9, Zinc finger nucleases, TALENs, etc.

Unit 13: Phenome-Genome relationships

Next generation Phenotyping: Genome-phenome relationship, definition of phenotyping, GxE interaction on phenome; Phenotyping bottleneck in establishing Phenotype-genotype relationships; The concepts of "phene and trait. Concepts of Plants to sensors and sensors to plants.