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Organisation of cells plant tissues (view source)
Revision as of 16:54, 1 August 2014
, 16:54, 1 August 2014→Notes for teachers
===Notes for teachers===
===Notes for teachers===
Complex permanent tissues are mainly of two types.They are water conducting '''xylem''' and food conducting '''phloem'''.
Complex permanent tissues are mainly of two types.They are water conducting '''xylem''' and food conducting '''phloem'''.Hence they are together called '''vascular tissues'''<br>
'''XYLEM'''<br>
'''XYLEM'''<br>
Xylem is a vascular tissue which transports water and minerals absorbed by the roots,to all parts of the plant, especially to the leaves.Hence it is called '''water conducting tissue'''.<br>
Xylem is a vascular tissue which transports water and minerals absorbed by the roots,to all parts of the plant, especially to the leaves.Hence it is called '''water conducting tissue'''.<br>
Tracheids and vessels are tubular structures which help in transport of water and minerals vertically.Vessels consist of sries of elongated cells joined end to end to form tube like structures.<br>
Tracheids and vessels are tubular structures which help in transport of water and minerals vertically.Vessels consist of sries of elongated cells joined end to end to form tube like structures.<br>
The xylem parenchyma stores food and helps in the sideways conduction of water.Xylem fibres are mainly supportive in function.<br>
The xylem parenchyma stores food and helps in the sideways conduction of water.Xylem fibres are mainly supportive in function.<br>
http://www.dr-evans.com/advancedbiology/images/xylemstructure.jpg
http://www.dr-evans.com/advancedbiology/images/xylemstructure.jpg<br>
'''PHLOEM'''<br>
Phloem is a complex tissue which conducts food to different parts of the plant.It is made up of four types of elements: sieve tubes, companion cells,phloem fibres and the phloem parenchyma.<br>
Sieve tubes are tubular cells with perforated walls called sieve plate.Phloem is unlike xylem in that materials can move in both directions in it. Phloem transports food from leaves to other parts of the plant.<br>
There are certain cells closely associated with sieve tube,called '''companion cells'''.They regulate the passage of food through sieve tubes. Except for phloem fibres, phloem cells are living cells.<br>
http://www.bbc.co.uk/bitesize/standard/biology/images/structure_phloem.gif
http://www.bbc.co.uk/bitesize/standard/biology/images/structure_phloem.gif