|[http://www.textbooksonline.tn.nic.in/Books/Std09/Std09-III-SSS-EM-1.pdf Structure and Physiological Functions of plants Page No 3-24] | |[http://www.textbooksonline.tn.nic.in/Books/Std09/Std09-III-SSS-EM-1.pdf Structure and Physiological Functions of plants Page No 3-24] |