294 



GROWTH 



balance is used, it should be adjusted by the addition of weights 

 at least six times daily, making the adjustments as late at night 

 and early in the morning as possible. 



A thermographic record should be made, and also a continuous 

 hygrometric registration, and both curves plotted on a sheet with 

 the accretions in weight. At certain periods in the development 



Fig. 141. Grand period of growth of Cucurbita pepo determined by accretions in 

 weight. Pollination was accomplished about September 18th, and the record was 

 begun September 21st. Continuous increase in weight ensued through a period 

 of 20 days ending October nth, which comprises the grand period of growth. After 

 the latter date, irregular gain and loss was measured for 17 days, after which the loss 

 in weight was continuous although slight. The intervals in the horizontal base line 

 denote days, and in the vertical lines each interval denotes gain or loss of 50 grams. 

 After Anderson. ' 



of a large cucurbitaceous fruit it may be expected to increase as 

 much as one gram per minute, and make a total daily increase 

 of over 700 g. 1 



372. Periodicity of Growth. The curves plotted' in the pre- 

 vious experiments demonstrate that the rate of growth is not 



1 Anderson, Alex. P. The grand period of growth in a fruit of Cucurbita pepo 

 determined by weight. Minn. Bot. Stud. 1: 238. 1 894-1898. 



