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Nutrition in plants By Taimoor
- 2. Or the algae in the sea ? Or the cacti in the desserts ? How does trees on the fertile plain obtain their nutrients ?
- 3. Review QuestionReview Question • Which mode of nutrition do the green plants carry out? A. Autotrophic nutrition B. Heterotrophic nutrition
- 4. Sorry! You’re wrong!Sorry! You’re wrong! • Heterotrophic nutrition is the mode of nutrition in which organisms have to depend on other organisms or dead organic matters as their food sources. Green plants, however, can make organic food by themselves using simple inorganic substances.
- 5. Very Good!Very Good! • Autotrophic nutrition is the mode of nutrition in which organisms can make organic food by themselves using simple inorganic substances. • The process by which the green plants obtain nutrients is called : Photosynthesis
- 6. Nature of photosynthesisNature of photosynthesis • Takes place in Chloroplast • Necessary factors : Carbon dioxide Water Sunlight Chlorophyll
- 7. Route of Carbon DioxideRoute of Carbon Dioxide for Photosynthesisfor Photosynthesis
- 10. Light energy is trapped by chlorophyll in chloroplast Light energy absorbed by chlorophyll splits water molecules into hydrogen and oxygen Oxygen is released as a gas through stoma to outside Hydrogen is fed into dark reaction Light reactionLight reaction
- 12. Oxygen is produce as the by-product of photosynthesis.
- 13. Dark reactionDark reaction No light is required; can take place either in light or darkness Hydrogen produced in light reaction combines with CO2 to form carbohydrates Water is formed as a by-product
- 14. Dark Reaction Water Oxygen Glucose (C6H12O6) Light Reaction H Summary of PhotosynthesisSummary of Photosynthesis 6 CO2 + 6 H20 C6H12O6 + 6 O2 Light Carbon Dioxide
- 15. Fate of carbohydrateFate of carbohydrate products in the plantproducts in the plant
- 16. carbohydrates (e.g. glucose) carbon dioxide and water photosynthesis release energy by respiration
- 17. convert into starch for storage because glucose is not a very good storage molecule carbohydrates (e.g. glucose) carbon dioxide and water photosynthesis
- 18. change into sucrose and is transported to other parts through phloem carbohydrates (e.g. glucose) carbon dioxide and water photosynthesis
- 19. carbon dioxide and water photosynthesis carbohydrates (e.g. glucose) fatty acids glycerol combine to form fats and oils to form cell membranes and as a food store
- 20. carbon dioxide and water photosynthesis carbohydrates (e.g. glucose) mineral salts from soil (e.g. NO3 - , SO4 2- ) amino acids join together to become protein molecules
- 22. DestarchingDestarching • Reason: – To avoid any existing starch in the leaves interfering with the result, and to show that any starch found after the experiment is produced during the period of investigation • Method: – By placing the plant in dark for at least 48 hours
- 23. To test a leaf for the presence of Starch
- 24. Why is the leaf first boiled in water ? Ans: Because the process can soften the leaf, break down the cuticle and kill the leaf. boiling water turn off Bunsen burner boiling alcohol hot water iodine white tile turn off Bunsen burner
- 25. Why is the leaf then boiled in alcohol ? Ans: To decolourize the leaf (to remove chlorophyll). boiling water turn off Bunsen burner boiling alcohol hot water iodine white tile turn off Bunsen burner
- 26. Why is it important to turn off the Bunsen burner when you are heating the alcohol ? Ans: Because alcohol catches fire easily. boiling water turn off Bunsen burner boiling alcohol hot water iodine white tile turn off Bunsen burner
- 27. Why is the leaf put in hot water after being boiled in alcohol ? Ans: Since the leaf becomes brittle after boiling in alcohol, so dipping it into hot water enables it to be softened. boiling water turn off Bunsen burner boiling alcohol hot water iodine white tile turn off Bunsen burner
- 28. What colour change can be observed if starch is present ? Ans: The leaf becomes blue-black when iodine solution is added to it. boiling water turn off Bunsen burner boiling alcohol hot water iodine white tile turn off Bunsen burner
- 29. To show that Chlorophyll is necessary for Photosynthesis
- 30. Which part of the leaf turns blue-black when treated with iodine solution ? Ans: Only the green part. green part purple part
- 31. Is chlorophyll necessary for photosynthesis ? Ans: Yes. green part purple part
- 32. What is the control in this experiment ? Ans: The green part of the leaf acts as the control. green part purple part
- 33. To show that Carbon Dioxide is necessary for Photosynthesis
- 34. Why is potassium hydroxide solution put in one of the flasks ? Ans: To absorb all the carbon dioxide in flask B. sunlight B A water potassium hydroxide solution
- 35. What happens to each leaf after testing the presence of starch at the end of the experiment ? Ans: The leaf in flask A changes to blue-black while the leaf in flask B stains brown. sunlight B A water potassium hydroxide solution
- 36. What do your results suggest about the relationship between carbon dioxide and photosynthesis ? Ans: Carbon dioxide is necessary for photosynthesis. sunlight B A water potassium hydroxide solution
- 37. Factors affectingFactors affecting the rate ofthe rate of photosynthesisphotosynthesis
- 38. Light intensity Rate of Photosynthesis
- 39. Carbon dioxide concentration Rate of Photosynthesis
- 40. Temperature Rate of Photosynthesis Temperature > 40℃ Rate & Stop soon
- 41. If no water, stomata close no gaseous exchange photosynthesis ceases
- 42. Why is PhotosynthesisWhy is Photosynthesis important ?important ? Green plants: the only organisms capable of trapping light to manufacture food from simple inorganic substances
- 43. Green plants(producers) starts the food chain & provide food for other organisms Why is PhotosynthesisWhy is Photosynthesis important ?important ?
- 44. Atmospheric carbon dioxide is absorbed & oxygen is released into the atmosphere which maintains the composition of the atmosphere constant Why is PhotosynthesisWhy is Photosynthesis important ?important ?
- 45. Parts of plant whereParts of plant where photosynthesis takes placephotosynthesis takes place Mainly in the leaf because –it contains a lot of chloroplasts –it is well adapted for performing photosynthesis
- 46. InternalInternal Structure of LeafStructure of Leaf
- 47. cuticle upper epidermis palisade mesophyll spongy mesophyll intercellular space (air space) guard cell lower epidermis cuticle stoma chloroplasts
- 48. Cross-sectionCross-section of a leaf ofof a leaf of dicotyledondicotyledon
- 49. upper epidermis protect internal tissues from mechanical damage and bacterial & fungal invasion
- 50. Cuticle • a waxy layer • prevent water loss from the leaf surface • protect the leaf
- 51. mesophyll
- 52. palisade mesophyll (layer) columnar cells closely packed together ∴absorb light more efficiently contains many chloroplasts
- 53. spongy mesophyll (layer) irregular cells loosely packed together to leave numerous large air spaces →allow rapid diffusion of gases throughout the leaf some (fewer than palisade mesophyll) chloroplasts for photosynthesis
- 54. lower epidermis same as upper epidermis except the cuticle is thinner
- 55. stomastoma (stomata)(stomata) opening which allows gases to pass through it to go into or out of the leaf
- 56. guard cellsguard cells control the size of stoma
- 57. StomaStoma stoma Guard cells thinner outer wall thicker inner wall
- 59. Internal Structure of LeafInternal Structure of Leaf xylem phloem
- 60. xylemxylem • to transport water and mineral salts towards the leaf • for mechanical support
- 61. phloemphloem • to transport organic substances (food/sugar/ glucose/ sucrose) away from the leaf
- 62. Adaptation of leafAdaptation of leaf to photosynthesisto photosynthesis
- 63. The leaf is thin decrease diffusion distance for gases & light The leaf is broad & flattened increase surface area to absorb more sunlight
- 64. Cuticle exists in upper epidermis and is transparent Allows most light to pass into photosynthetic mesophyll tissues
- 65. Palisade mesophyll cells are closely packed and contain many chloroplasts To carry out photosynthesis more efficiently
- 66. Spongy mesophyll cells are loosely packed with numerous large air spaces To allow rapid diffusion of gases throughout the leaf
- 67. Numerous stomata on lower epidermis To allow rapid gaseous exchange with the atmosphere
- 68. Extensive vein system • Allow sufficient water to reach the cells in the leaf • To carry food away to other parts of the plant
- 69. Mineral requirementsMineral requirements in plantsin plants • In order to synthesize amino acids, nitrate ions which must be taken into the plant from the soil through the root • Other minerals are also necessary to maintain the life of the plant (N, Mg, P, K, S, etc)
- 70. The importance ofThe importance of nitrogennitrogen • For synthesis of proteins, chlorophyll, etc • Taken in form of nitrate ions • Deficiency symptoms: – Little growth ( - no protein made) – Yellowing of leaves ( - no chlorophyll made)
- 71. The importance ofThe importance of magnesiummagnesium • Essential component of chlorophyll • Deficiency symptoms: – Yellowing of leaves (no chlorophyll made) – Poor growth (no food manufactured because of lack of chlorophyll)
- 72. Use of fertilizers inUse of fertilizers in agricultureagriculture • Continuous harvesting crops removes valuable mineral salts from soil ∴Fertilizers are added to replace such loss • Two kinds of fertilizers: – Natural fertilizers – Chemical fertilizers
- 73. Natural fertilizersNatural fertilizers • From manure • Organic compounds in it are decomposed by the bacteria in soil to form mineral salts
- 74. Chemical fertilizersChemical fertilizers • Mainly nitrogenous and phosphorous compounds manufactured artificially
- 75. Comparison between naturalComparison between natural and chemical fertilizersand chemical fertilizers Natural fertilizers Chemical fertilizers Contain humus which can improve soil texture No humus so cannot improve soil texture Less soluble in water so less likely to be washed away Very soluble in water so more likely to be washed away
- 76. Comparison between naturalComparison between natural and chemical fertilizersand chemical fertilizers Natural fertilizers Chemical fertilizers Less soluble in water so more difficult to be absorbed Very soluble in water so easier to be absorbed More readily to be used by the plants Time is needed for the decomposition to complete before nutrients are available to plants Very expensiveMuch cheaper