CHANGES ACCOMPANYING BREAKING OF REST PERIOD 45 



untreated twigs remained dormant. Acetic acid baths gave similar 

 results. Quercus coccinea twigs did not respond to these treatments. 



A number of different solutions were tried for their forcing 

 qualities. Ash, oak, apple, plum, and maple twigs were used. The 

 twigs were immersed in the solutions for twelve hours on January 

 20, 1914. Those treatments proving effective were: For ash, 5 

 per cent NaNO 3 and 5 per cent ammonium oxalate; for maple, 0.5 

 per cent KC1; for plum, 1 per cent ammonium oxalate, 0.5 per cent 

 KC1, 5 per cent NaNO 3 and 0.5 per cent CuSO 4 ; for apple, 1 per 

 cent and 0.5 per cent CuSC>4 and 1 per cent KC1. 



Good results were obtained with MnO 2 treatments. On Jan- 

 uary 19, 1914, ash, apple and oak twigs were dipped in MnO 2 paste 

 made of powdered MnO 2 and water. The paste adhered to the 

 twigs and formed a slate colored coating when dry. These treated 

 twigs, also normal ones, were placed in a greenhouse in water. Fig. 

 10 shows the results one month following treatment. The buds on 

 the treated ash twigs had swollen very much compared with those 

 on untreated ones. The former had also formed an abundance of 

 callus tissue. The buds on treated oak twigs were much more active 

 than those which received no treatment. Apparently, the apple 

 does not respond to the MnO 2 treatment so late in the year. It 

 should be mentioned that the MnO 2 might have influenced the twigs 

 indirectly by absorbing heat due to its dark color. 1 The apple, 

 however, is normally affected by heat, and the MnO 2 treatment 

 was non-toxic since both check and treated buds began to grow at 

 about the same time. 



DISCUSSION OF RESULTS OF RESPIRATION EXPERIMENTS 



AND OTHER TESTS 



Many of the results presented in this paper supply experimental 

 proof in support of the theory of Klebs, viz., that after length growth 

 has ceased in plants, the leaves remain green and active and continue 

 to assimilate organic foods which accumulate in considerable quan- 

 tities. The rest period breaking agents apparently do stimulate 

 fermentative activity. In most cases when diastase enzymes are 

 made more active, earlier growth is induced. However, this is not 

 always the case. A striking example is found in the case of the ash. 

 This species has a very high diastatic activity, yet it forces with 

 much difficulty. The same was found to be true of several varieties 



1. Whitten, J. C. Winter Protection of the Peach. Bulletin No. 38, 

 Missouri Agr. Exp. Sta. 



