102 



PLANT PROPAGATION" 



Both water sprouts and suckers commonly follow over- 

 pruning. They show an undesirable loss of balance 

 between root system and top. In cold climates water 

 sprouts often winterkill. Therefore, they are best re- 

 moved promptly and with clean cuts. Where practical, 

 careful root pruning will tend to overcome this condition. 

 150. Origin of roots in cuttings. In making stem cut- 

 tings the usual practice is to "cut to a node" ; i. e., stems 

 are cut just below buds. The reason for this is that with 



most plants a larger pro- 

 portion of cuttings will 

 "strike root" than if the 

 cuts are made farther 

 away from the nodes. 

 True buds of themselves, 

 however, exercise no in- 

 fluence in the production 

 of roots, for if buried in 

 the earth or other me- 

 dium, they do not grow. 

 The reason roots form 

 best near the nodes is 

 believed to be that stem 

 tissues at such points are 

 richer in plant food stored 

 there to assist the 

 bud should it start 

 growth. While many 

 stems made into cuttings 

 will root at any point, it is a rule that roots arise most 

 freely at or very near the bases of the cuttings, whether 

 "cut to a node" or not.' 



Root origin is always in adventitious buds, usually 

 formed beneath the bark or the callus, but always in the 

 primary (meristematic) tissue, the center of the cambium 

 layer. This tissue is composed of undifferentiated cells. 

 Adventitious buds may develop in any part of a plant 



i. Grape cuttings showing callus, 

 showing roots. 



