88 PLANT GROWTH SUBSTANCES 



» 

 it should be possible to induce flowering of plants at will and to force 

 flowers to grow at unusual places. We can imagine plants with flowers 

 on internodes, on leaves, and even on roots. 



At the present time there appears to be considerable variation in the 

 time of ripening of fruit. Under the influence of chemicals the time of 

 ripening should fit into our needs. During the past season it has been 

 shown that apples treated with certain hormone-like chemicals ripened 

 prematurely. To a lesser degree this has been noticed for tomatoes. 

 Tomato flavors are not affected under the influence of the chemical. 

 Apples, however, change flavor and consistency, but the fact that modi- 

 fications in time of ripening have been demonstrated offers encourage- 

 ment for practical methods applicable to all or many fruits. 



Since it has been demonstrated that fruit buds can be delayed through 

 treatment with growth substances, one is led to the assumption that 

 fruiting of tropical species and flowering of plants in general can be 

 staggered to extend throughout the entire season. Mangoes, for example, 

 flower and ripen fruit at definite periods of the year. During the rest of 

 the year they are not available as food. Since this is an important tropical 

 food, it would be desirable to extend it throughout the season. This 

 should become a reality by the proper hormone applications to growing 

 buds. The idea is particularly applicable to tropical plants because the 

 temperature and other growing conditions would not limit the time of 

 fruiting. We should, however, be able also to stagger flowering of spring 

 shrubs in the north so that we may enjoy them over longer periods. 



Without making further predictions, it appears that the field of plant 

 hormones presents a challenge for scientists with varied attacks. From 

 the fundamental research angle, it might be said that the work is just 

 beginning. We have found only a few natural hormones, and we still 

 know little about how hormones work. From the standpoint of horti- 

 cultural applications progress has been more rapid than in fundamental 

 research, and the results so spectacular that interest in the subject is 

 now sweeping the world. Research holds much for the future and more 

 important applications are sure to be made. 



There is much competition in the fields covered by this paper. Perhaps 

 that is why progress has been rapid. Research in some phases of the 

 subject can be done by amateurs and practical horlicullurists as well 

 as by trained scientists. It is well to recognize the fact that several 

 techniques have played a part in solving difficult problems. We take 



