CHAPTER III 



REGENERATION AND MASS RELATION IN ISOLATED 

 LEAVES OF BRYOPHYLLUM 



It will be shown, first, that equal masses of sister leaves of 

 Bryophyllum calycinum produce, in equal time and under equal 

 conditions of illumination, temperature, moisture, and chemical 

 environment, equal quantities of shoots and roots. 



Experiment 1. — Seven pairs of sister leaves of equal size were 

 detached from stems and were suspended in an aquarium so 

 that their apices dipped in water (Fig. 14). The experiment 

 lasted from Mar. 20 to Apr. 11, 1923. From the notches near or 

 in the water new roots and shoots arose. It was expected that 

 each leaf of a pair would produce the same mass of roots and 

 shoots from the notches, or that the 7 leaves, 1 each from a pair, 

 would produce the same mass of roots and shoots as their 7 

 sister leaves, per gram dry weight of leaves. This was found to 

 be approximately correct. The roots and shoots were removed 

 from the leaves after 22 days, and leaves, roots, and shoots were 

 dried for 24 hours in an electric oven at about 100°C. The two 

 sets of sister leaves are designated as Set I and Set II in Table I. 



Each of the two sets of 7 leaves produced therefore approx- 

 imately equal masses of dry weight of shoots and roots per gram 

 dry weight of leaves. 



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