RESPONSES TO ENVIRONMENT BY PLANTS IN THE VEGETATIVE PHASE 



553 



leaves, which were half expanded when the kinetin was added to the 

 solution, there is no change in area, but for the second and younger 

 pair the final area is increased. In contrast, the third and fourth still 

 younger pairs fail to expand. Unlike 1,3-diphenylurea, kinetin causes 



TABLE IV 



The Effects of Kinetin on Leaf Expansion and Intemode 

 Length in Salvinia natans 



Concentration of 

 Kinetin 



(mg/1) 





 3.0 





 3.0 



1st 



Sequence of Leaves 

 2nd 3rd 



4th 



Mean Area per Pair of Leaves (cm^) 



1.13 1.18 1.13 0.42 



1.18 1.47 — — 



Sequence of Intemodes 

 2nd 3rd 



1st 



Intemode Length (mm) 



9.5 , 9.3 6.3 



8.1 5.25 — 



II o 



lOO 



- o 



o 

 o 



o 



i; ioo|- o 



c 



O 



U 



- — - 90 - 



D 



-• 801- 



a. 



cv 



70 



lOO 



90 



so 



o-o 



/ 



(a) T.I.B.A. 



o-o 



c>o. 



( b) I . A . A . 



(c) G.A. 



I 2 



External Cone. mg/l. 



Figure 17. Changes in the area per leaf of Salvinia natans induced by (a) 

 2,3,5-triiodobenzoic acid, (b) 3-indolylacetic acid, and (c) gibberellic acid. 



