ICSE Class 8 Biology, Unit 1: Transport of Food and Minerals in Plants

What this unit aims at

This theme deals with the movement of water containing minerals and food with plants. The exchange of water, gases, minerals and other substances into and out of the cells and also between neighbouring cells, takes place through a system called transportation system. In unicellular organisms (Chlamydomonas) and simple multicellular organisms like Spirogyra , diffusion is a major method of transportation. Diffusion of water across a semipermeable membrane is called osmosis. In complex higher plants because of enormity of size and complex organization, there is an elaborate transportation system and transport occurs through a vascular system of independent channels or conducting tubes (xylem and phloem). In addition to transport, xylem tissue also provides mechanical strength to the plant body. Essential mineral nutrients are also needed for the healthy growth of plant. In the absence or n

Your child should be able to

• learn about the existence of a transport system inside the plant body of complex multicellular higher plants
• explain that transport in unicellular and simple multicellular plants takes place by diffusion
• define and discuss diffusion, osmosis, transpiration, root pressure
• perform experiments and demonstrate the process of osmosis
• realize that the minerals required are either micronutrients or macronutrients depending upon the quantity required by the plants
• relate that the deficiency or lack of essential nutrients leads to specific symptoms and diseases. define transpiration, interpret its role in xylem transport and know about the factors affecting rate of transpiration. demonstrate transpiration through simple experiments

Key concepts in this unit

• Transport in Plants: Diffusion – definition;
• Transport in Plants: Osmosis – definition, example, semipermeable membrane, root pressure; active transport.
• Transport in Plants: Transpiration - definition, importance and factors affecting transpiration.
• Transport in Plants: Structure and function of Xylem and Phloem in detail;
• Transport in Plants: Importance of minerals: macro and micro- nutrients; three deficiency diseases caused by lack of these essential nutrients.