9.2 How do plants obtain food, water and minerals? build up own organic nutrients using simple inorganic substances Plants make their own food This is called autotrophic nutrition

9.2 How do plants obtain food, water and minerals? All other organisms depend on autotrophs for food They are heterotrophs

9.2 How do plants obtain food, water and minerals? Have you ever grown a plotted plant? Why is fertiliser added to the soil regularly? What does fertiliser contain? The need for minerals

9.2 How do plants obtain food, water and minerals?

Elements needed by plants Experiment 9.1 Major elements needed in relatively large amountsneeded in relatively large amounts e.g. nitrogen, phosphorus, magnesium, sulphur, potassium, calcium and irone.g. nitrogen, phosphorus, magnesium, sulphur, potassium, calcium and iron Trace elements needed in relatively small amountsneeded in relatively small amounts e.g. copper, molybdenum, sodium, boron, zinc and manganesee.g. copper, molybdenum, sodium, boron, zinc and manganese

9.2 How do plants obtain food, water and minerals? Nitrogen comes from nitrates and ammonium salts in soil is used to synthesise proteins nitrogen-deficient healthy leaf lead to chlorosis

9.2 How do plants obtain food, water and minerals? Phosphorus component of nucleic acids, cell membranes, ATP and several coenzymes phosphorus-deficient healthy leaf lead to poor growth and turn purple

9.2 How do plants obtain food, water and minerals? Magnesium is needed to make chlorophyll healthy leaf magnesium-deficient lead to chlorosis Biology and society

9.2 How do plants obtain food, water and minerals? Absorption of water and minerals

9.2 How do plants obtain food, water and minerals? In August 2007, part of a more than 200 year old tree in Kowloon Park fell down suddenly...

9.2 How do plants obtain food, water and minerals? It was believed that the roots had been damaged. Why can’t a tree grow healthily if its roots are damaged? Why can’t a tree grow healthily if its roots are damaged?

9.2 How do plants obtain food, water and minerals? Different kind of roots

9.2 How do plants obtain food, water and minerals?

Root hairs in a germinating seed

9.2 How do plants obtain food, water and minerals? A Root hair

9.2 How do plants obtain food, water and minerals? Root hair – an extension of a root epidermal cell

9.2 How do plants obtain food, water and minerals? 2. Growing point cells can divide actively by mitosis 1. Root cap prevents delicate cells at the growing point from damage as root grows deeper into soil Longitudinal section of a dicotyledonous root

9.2 How do plants obtain food, water and minerals? 4. Region of differentiation cell develop into specialised tissues and structures Longitudinal section of a dicotyledonous root 3. Region of elongation cells absorb water and elongate have large vacuoles

9.2 How do plants obtain food, water and minerals? Transverse section of a dicotyledonous root

9.2 How do plants obtain food, water and minerals? 1. Epidermis protects inner tissues not covered by cuticle, thus water can be absorbed easily 2. Root hairs increase the surface area for uptake of water and minerals 3. Cortex allows the passage of water and mineral salts across the root stores food as starch

9.2 How do plants obtain food, water and minerals? Xylem Phloem 4. Vascular bundle transports water, minerals and food made up of xylem and phloem

9.2 How do plants obtain food, water and minerals? Longitudinal section of root tip region of elongation root cap growing point

9.2 How do plants obtain food, water and minerals? Transverse section of root tip epidermis cortex xylem phloem vascular bundle

9.2 How do plants obtain food, water and minerals? Absorption of water by roots soil particlesepidermiscortex xylem vessel

9.2 How do plants obtain food, water and minerals? 1. The water potential of the soil water is higher than that of the root hair. Water enters the root hair by osmosis. soil particlesepidermiscortex xylem vessel

9.2 How do plants obtain food, water and minerals? soil particlesepidermiscortex xylem vessel 2. The water potential of the cytoplasm and cell sap of the epidermal cells is higher than that of cortex cells. Water passes from epidermal cells to cortex by osmosis.

9.2 How do plants obtain food, water and minerals? soil particlesepidermiscortex 3. Water passes across the cortex from cell to cell by osmosis or moves along the cell walls. xylem vessel

9.2 How do plants obtain food, water and minerals? soil particlesepidermiscortex 4. Water is drawn into the xylem vessels. xylem vessel

9.2 How do plants obtain food, water and minerals? Absorption of minerals by roots Mineral ions are taken up into the root against concentration gradient by active transport Active transport requires metabolic energy Quick Practice

9.2 How do plants obtain food, water and minerals? Mycorrhizae (reference) Most plants form mutually beneficial relationships with fungi, which facilitate the absorption of water and minerals from the soil Roots and fungi form mycorrhizae, symbiotic structures consisting of plant roots united with fungal hyphae Figure mm

9.2 How do plants obtain food, water and minerals? How do plants obtain nutrients? Plants build up their own organic nutrients by using inorganic substances through the process of photosynthesis. This mode of nutrition is called autotrophic nutrition. Plants are called autotrophs.

9.2 How do plants obtain food, water and minerals? What substances do plants need for growth and how do plants obtain these substances? Plants need carbon dioxide and water as well as minerals for growth. Water and minerals are absorbed from the soil by the roots. Carbon dioxide is obtained from the atmosphere.

9.2 How do plants obtain food, water and minerals? What minerals does a plant need? Mineral elements needed by plants can be divided into two types: (1)major elements, which are needed in larger amounts (e.g. nitrogen, phosphorus, magnesium etc.) (2)trace elements, which are needed in much smaller amounts (e.g. copper, sodium etc.)

9.2 How do plants obtain food, water and minerals? What are the functions of different elements in supporting plant growth? MineralsFor makingDeficiency symptoms Nitrogen Phosphorus Magnesium - proteins - chlorophyll molecules - nucleic acids, cell membrane, ATP and several coenzymes - chlorophyll molecules - poor growth - yellowing of leaves i.e. chlorosis - poor growth - turn green leaves purple - poor growth - yellowing of leaves i.e. chlorosis

9.2 How do plants obtain food, water and minerals? How are roots adapted to the function of water and mineral absorption? StructureAdaptation Root hairs Epidermis -Long and fine structures which can easily grow between soil particles -The great numbers of root hairs increase the surface area for uptake of water and mineral salts in the soil -Absence of cuticle and thus water can enter easily

9.2 How do plants obtain food, water and minerals? By which processes do water and minerals enter into a plant? Water enters into a plant by osmosis. Minerals usually enter by active transport.