Pract Practica icall 6 Effec Effects ts of variou various s trea treatme tments nts on piece pieces s of of stai stained ned potat potato o tiss tissues ues __________________________________________________________________________ __________________________________________________________________________ Objective: To investigate the effects of various treatments on pieces of stained potato tissues Apparatus and Materials: Pen knife White tile Forceps 8 test tubes Petri dish eaker !top "atch
Potato Methylene blue solution 50% ethanol
Procedures: #$ ut four four cubes cubes from from the the potato potato provide provided& d& each each appro'i appro'imatel mately y #0 mm mm ' #0 mm ' 5 mm$ Trim Trim off off any any peel "hich is still attached$ ($ Place Place the potato cubes cubes in a small beaker beaker&& immerse immerse them them in methylene methylene blue solution solution for #0 #0 minutes$ minutes$ )se only enough methylene blue to cover them$ *$ +fter +fter #0 minutes& minutes& pour off the the methylene methylene blue blue solution solution and "ash the cubes cubes "ith tap tap "ater until until the "ater contains little or no stain$ Then cover the cube "ith tap "ater$ ,$ -abe -abell fou fourr tes testt tub tubes es A, B, C and D and D$$ To each of the tubes +& and & add 5cm * of distilled "ater& to tube . add 5 cm* of 50% ethanol$ 5$ Place Place tube tube + in in boiling boiling "ate "ater& r& tube tube in a "ater "ater bath bath of *8 o to ,( o and tube and . at room temperature$ /$ +fter +fter 5 minutes& minutes& add one stain stained ed potato potato cube to each of the four test test tubes$ tubes$ !tart !tart the stop stop "atch "atch immediately$ $ +fter +fter ( minutes& minutes& remove tubes tubes + and from the "ater "ater baths baths and place them them in the rack "ith "ith tubes and .$ !hake the tubes$ 8$ !eparate !eparate the tissue tissue from solution solutions$ s$ .o this by pouring pouring a"ay a"ay the li1uid li1uid into another another the correspondi corresponding ng test tubes labeled +2 to .2$ 3$ 4ecord 4ecord your your obser observat vation ions s of each each test tube tube$$ • What is the texture and colour of the tissue? • What is the colour of the liquid and how much light can pass through? • How will you record the difference in intensity of colouration of the liquid? esults: !able ": !ube
#nt #ntensi ensit$ t$ of blue lue co colourat ration ion in li%u i%uid &arbitrar$ unit'
A B C D +rbitrary units units , 6 most intense& intense& # 6 least intense intense 34
Observation of potato tissue
Discussions: From the data you have collected& account fully for the observations you have made and dra" clear conclusions& using your kno"ledge and understanding$ )se the follo"ing 1uestions as guidelines$ #$ Why should the surface area be kept constant for each piece of potato tissue7 ($ Why are the potato cubes stained "ith methylene blue "hy is a colour stain chosen97 *$ What is the purpose of having tube placed in "ater at room temperature7 Why isn2t tube . placed at high temperature7 ,$ What happen to the stained potato cubes "hen they are placed in "ater at room temperature7 5$ What are the effects of temperature on potato cubes in tubes +& and 7 /$ What are the effects of the ethanol on the potato cubes7 $ !tate the reason for using e1ual volumes of li1uids in all tubes$ 8$ :'plain the significance of the 5 minutes incubation before adding the potato cubes$ 3$ :'plain the significance of the ( minutes incubation after adding the potato cubes$ #0$ :'plain the significance of separating the tissue from solutions after the ( minute incubation$
Effects of various treatments on pieces of stained potato tissues
esults: !able " !ube
#ntensit$ of blue colouration in li%uid &arbitrar$ unit'
Observation of potato tissue
A B C D +rbitrary units , 6 most intense& # 6 least intense Discussions: #$ Why should the surface area be kept constant for each piece of potato tissue7
($ Why are the potato cubes stained "ith methylene blue "hy is a colour stain chosen97
*$ What is the purpose of having tube placed in "ater at room temperature7 Why isn2t tube . placed at high temperature7
,$ What happen to the stained potato cubes "hen they are placed in "ater at room temperature7
5$ What are the effects of temperature on potato cubes in tubes +& and 7
36
/$ What are the effects of the ethanol on the potato cubes7
$ !tate the reason for using e1ual volumes of li1uids in all tubes$
8$ :'plain the significance of the 5 minutes incubation before adding the potato cubes$
3$ :'plain the significance of the ( minutes incubation after adding the potato cubes$
#0$ :'plain the significance of separating the tissue from solutions after the ( minute incubation$
