CHEMICAL CHANGES DURING GERMINATION 55 



(iii.) Chlorophyll solutions on exposure to light 

 rapidly lose their colour, only a faint yellow tinge 

 remaining. This change is due to oxidation. 



(iv.) A few drops of HNO3 shaken up with the 

 chlorophyll solution will bring about a similar change. 



CHAPTER IV 



Chemical Changes during Germination 

 AND Growth 



During the germination of a seed, for which certain conditions 

 of temperature, moisture, and ventilation are necessary, most of 

 the substances in the seed undergo chemical changes, the general 

 trend of such changes being the production of soluble bodies from 

 insoluble substances. These changes are brought about by the 

 action of unorganised ferments or enzymes (cytase, diastase) 

 present in all seeds, and which undergo a considerable increase 

 both in quantity and in activity during the process of germination. 

 The substances rendered soluble are reserve food-materials for the 

 young plant, and they undergo this change in order that they may 

 dissolve in the sap and be transported to those parts of the plant 

 where they are required. 



Cellulose is rendered soluble by the cytase, starch is converted 

 into dextrins, and then to maltose by the diastase, insoluble 

 proteins are rendered soluble, and fat is converted into starch 

 and then into maltose. 



34. Conversion of Starch to Sugar. 



Forty grains of sound barley are germinated on 

 damp filter paper until the shoot is about an inch long. 



They are then ground up in a mortar with a little 

 water, and the solution is filtered. This solution contains 

 maltose, the presence of which can be shown by 

 Fehling's test. The red precipitate of cuprous oxide is 

 produced less easily than in the case of glucose ; hence 

 on boiling another portion of the solution for a short 



