92 CHEMISTRY OF PLANT LIFE 



natural antiseptic conditions for all wounds of the outer surfaces 

 of the stem of the plant. In fact, it is easily conceivable that at 

 least one of the reasons for the failure of the processes of decay of 

 plant tissues to set in until after the death of the cells, is that dur- 

 ing living, respiratory activity these antiseptic glucosides are so 

 generally present in the tissues. 



Further, it has been fairly well established that the " chro- 

 mogens," or mother-substances of the pigments, which, under the 

 influence of oxidase enzymes, serve to regulate the respiratory 

 activities of the plant are essentially glucosidic in character. 

 This, and other, functions of the pigments, most of which are glu- 

 cosides, will be discussed at some length in the chapter dealing 

 with the Pigments (Chapter VIII). 



Many gaseous anaesthetics are known to have a marked effect 

 in stimulating plant growth. In a number of cases, it has been 

 shown that the contact of plant tissues with these anaesthetics 

 brings about an interaction of the enzyme and glucoside which 

 are present in the tissue, with the consequent hydrolysis of the 

 latter, setting free its characteristic components. This observa- 

 tion has led to the supposition that many of the organic constit- 

 uents of glucosides are definite plant stimulants, to which the 

 name " hormones " has been applied. There is considerable 

 experimental evidence to support this conception that glucosides 

 may be the source of stimulating hormone substances, which will 

 be discussed more in detail in the chapter dealing with these plant 

 stimulants (Chapter XVII). 



Glucosides may also serve as the mechanism for putting out 

 of action of harmful products which may appear in the tissues as 

 the result of abnormal conditions. These harmful substances 

 may be rendered soluble by combination with sugars and so trans- 

 posed by osmosis to some other part of the plant. The abnor- 

 mally large percentages of glucosides which are present in certain 

 species of plants during unfavorable climatic conditions lends 

 some support to this view. 



Finally, it may be assumed that easily oxidizable substances, 

 such as aldehydes and acids, are possibly protected against too rapid, 

 or premature, oxidation by being transformed into glucosides. 



In general, it may be said that the glucosides seem to serve as 

 the regulatory, protective, and sanatory agencies of the plant 

 mechanism. 



