38 



the period of tillering. The entire plant contains about twenty 

 percent of pentosane and thirty percent of crude fibre, from the early 

 stage of growth until the time of flowering, Later, at the time of 

 maturity, there is reduction in the percentage of these carbohydrates. 

 This reduction does not mean that the absolute amount of pentosane 

 and crude fibre produced in the entire plant diminishes, but that a 

 considerable production of starch during maturation lowers the percent- 

 age of these carbohydrates. On the whole, the variation in the 

 percentage of pentosane throughout the plant's life seems to have a 

 certain relation to the production of crude fibre. A similar phe- 

 nomenon is found in the development of some other plants. How- 

 ever, the amounts of these carbohydrates are not always in the same 

 proportions : the ratio of pentosane to crude fibre fluctuates from about 

 $2% to 72%, becoming greater towards maturity. 



The percentage of crude fibre in the roots is very high through- 

 out the plant's life. But the percentage of pentosane, which maint- 

 ains a high rate till the time of flowering, diminishes at maturity, 

 owing to a rather large increase of crude fibre ; yet, be it noted, the 

 absolute amount of pentosane does not decrease during maturation. 



The stems are found to have an increase in the absolute 

 amounts of their pentosane and crude fibre at successive stages of 

 growth. The percentage of pentosane contained in the stems is 

 already fairly high in the period of tillering, and drops a little in 

 the course of development, finally increasing again towards maturity 

 to a much greater extent than at the stage of tillering. Such fluct- 

 uations are more clearly observed in the percentage of crude fibre 

 in the stems. The increase of these carbohydrates at maturity is 

 caused, in a large degree, by the considerable decrease in the 

 absolute amount of starch that is reserved in the stems. In a word, 

 the fluctuations in the percentages of pentosane and crude fibre are 

 greatly influenced by the amount of protein and starch that are 

 produced in the stems. 



