CHANGES ACCOMPANYING BREAKING OF REST PERIOD 43 



on. Toward the close of the dormant season it was found difficult 

 to get any marked acceleration of growth. Heavy dosage of a 

 given agent which produced earlier growth in twigs during December 

 or early January, was found to injure the twigs and buds if given 

 later in the season. The specific behavior of some twigs has already 

 been referred to in connection with some of the experiments. 



A few observations might be of interest in this connection. 



In some cases a very strong does of ether stimulated the terminal 

 bud only, while a dose only half as strong caused the laterals as well 

 as the terminals to grow earlier than untreated buds. In twigs 

 which were frozen, the basal buds grew earlier than those nearer the 

 tip. In many cases, a given dose of ether stimulated the leaf buds 

 while the flower buds were killed by the treatment. In several cases 

 mechanical injury just below or near a bud caused that bud to burst 

 into growth while the buds above and below remained dormant. 

 As a rule, desiccation produced the most uniform results, i.e., the 

 drying caused all laterals as well as terminals to come out about the 

 same time. Usually on untreated twigs the lateral buds came out 

 very irregularly, some of them opening several days before others. 



On January 16, 1914, a number of similar, vigorous, one-year- 

 old King David apple twigs were collected. All were about 75 cm. 

 long. Some were left entire; some were cut in half; while in other 

 cases the terminal one-third was cut off. The lower cut surfaces of 

 each lot of twigs were put in beakers of water and placed in the 

 greenhouse. The photograph (Fig. 8) shows the general appearance 

 of the twigs after one month. The twigs at A were those which were 

 left entire. Very few terminal buds had opened. The laterals of 

 the lower portions of the twigs had made a good growth. Most of 

 the laterals farther up on the twig were dormant. The lower two- 

 thirds of some of the twigs are shown at B. In this case the buds 

 nearest the injured surface made a very vigorous growth. The 

 remaining lateral buds also made more or less growth. The twigs 

 at C were the upper parts of those shown in B. The terminal 

 portions made no lateral growth. The terminal buds, however, 

 were beginning to grow somewhat more vigorously than those at 

 A or D. The upper halves of those twigs which were cut into two equal 

 parts, are shown at D. In these, the terminals made some growth. 

 Some of the lateral buds began growing rather vigorously but many 

 of them made only a feeble growth. 



The behavior of these twigs indicates that the water supply which 

 reached the buds was one of the important factors in their 

 development. It should be mentioned that the buds in all cases 

 were fully turgid. 



