82 



Table 27. Showing the Relative Hardiness of Young Rapidly 

 Growing Leaves and Old Mature Leaves. 



Material 



Date 



Tem- 

 pera- 

 ture 



Results 



Jonathan apple twigs 

 thawed slowly. 



Jonathan apple twigs 

 thawed rapidly .... 



Jonathan apple 



Young Jonathan 

 apple 



Jonathan apple. 



Salway peach 



Elberta peach twigs... 



Elberta peach. 



Grape shoots. 



May 17/13 

 May 17,'13 



May 24,'13 

 June 7/13 



June 12,'13 



May 24,'13 

 June 7,'13 



June 12/13 



May 24/13 



-4 

 -4 



-4 

 -5 



-4.5 



-4 

 -5 



-4.5 



2 small terminal leaflets of each 

 of the 4 twigs were injured. 

 2 twigs had 4 terminal leaflets in- 

 jured; 1 twig had 5 end leaves in- 

 jured; 1 twig had 6 end leaves in- 

 jured. All mature leaves were un- 

 injured. 



Slight injury in terminal part. Ma- 

 ture leaves uninjured. 



Terminal leaflets injured. Mature 

 leaves green and turgid: slight in- 

 jury being confined to leaf veins. 

 In terminals, 2 to 5 in. of the twigs, 

 cortex, cambium, sap wood and 

 pith were severely injured, cortex 

 and _ pith being hardier. Older 

 portion was much hardier. 



In freezer with peach on same date. 

 Injury not so great as that to 

 peach, but younger terminal leaves 

 showed considerable injury while 



older leaves at the base of the twigs 

 were uninjured. 



Very slight injury in terminal part. 

 Mature leaves uninjured. 



All terminal buds killed. Mature 

 leaves, including those below 2 in. 

 of terminal, had mid-ribs and veins 

 killed,_ with other tissues apparent- 

 ly_ uninjured. Small leaves ad- 

 joining large old leaves uninjured. 

 In terminal 3 in. all tissues were 

 injured. Of the remaining portion 

 only the cambium showed severe 

 injury. 



Slowly and rapidly growing twigs 

 were used. Only 2 to 3 terminal 

 leaves of the slowly growing twigs 

 showed injury, while on the rap- 

 idly growing twigs 7 to 8 terminal 

 leaves were entirely killed. Oldest 

 leaves at base of all twigs were un- 

 injured. 



Youngest 10 leaves of 8 in. shoot 

 dead. Mature % of 18 in. shoot 

 uninjured. 



