Mar. i, 1921 



Utilization of Cotyledons of Bean Seedlings 



879 



In Table II will be seen the percentage distribution of phosphorus, cal- 

 cium, and magnesium in the ash of the separate parts of the beans anal- 

 yzed. Here we see that the percentages of phosphorus in the normal 

 cotyledons and those exhausted under the given conditions are fairly 

 constant, ranging from 32.62 in the exhausted cotyledons grown in soil 

 to 36.66 in the normal whole cotyledons of the same lot. The percentage 

 of phosphorus in the ash of the exhausted cotyledons of beans grown in 

 distilled water very closely approximates that in the ash of the normal 

 cotyledons of the same lot being 35.18 and 34.22, respectively. 



Table II. — Analyses of the ash of beans and of the several parts 



Material analyzed. 



Normal cotyledons 



Embryos 



Integuments 



Normal whole beans 



Exhausted cotyledons (grown in soil). .. . 

 Exhausted cotyledons (grown in water) . 

 Normal cotyledons" 



Phosphorus 

 as PsOs. 



Per cent. 

 36.66 

 44- 5° 

 3-44 

 28.33 

 32. 62 

 35-i8 

 34.22 



Calcium as 

 CaO. 



Per cent. 



•47 

 • J 7 

 •73 

 •32 

 •45 

 •45 

 ■30 



Magnesium 

 as MgO. 



Per cent. 

 4.46 

 6.88 

 9.81 



4-75 



8.48 

 3.87 



3- 27 



a A different lot of Kentucky Wonder beans from those grown in soil. 



In Table III will be seen the comparative amounts of dry matter, crude 

 ash, and the elements phosphorus, calcium, and magnesium used by the 

 seedlings grown in distilled water and those grown in garden soil. Here 

 we see that 92.3 per cent of the dry matter, 92 per cent of the total ash, 

 92.8 per cent of the phosphorus, 81.4 per cent of the calcium, and 84.9 per 

 cent of the magnesium of the cotyledons of beans grown in garden soil was 

 translocated to other parts of the plant before the cotyledons ceased to 

 function as a source of food supply. We see also that only 58.2 per cent 

 of the dry matter, 54.2 per cent of the total ash, 42.9 per cent of the phos- 

 phorus, 1 4. 1 per cent of the calcium, and 60 per cent of the magnesium in 

 the cotyledons was utilized by the seedlings grown in distilled water 

 cultures. 



Table III. 



-Comparison of percentages of material translocated from the cotyledons of 

 beans grown in distilled water and in soil 



Material translocated. 



Dry matter 

 Crude ash. . 

 Phosphorus 

 Calcium . . . 

 Magnesium 



In distilled 

 water. 



58.2 

 54-2 



5 2 -9 

 14. 1 

 60. o 



