Oct. 14, 1818 



Hardening Process in Plants 



97 



into a lipoid fraction (P^), a water-soluble fraction (Fg), and a fraction 

 insoluble in alcohol and water (F3). Samples of 100 gm., green weight, 

 were collected from hardened (Hi, Hj) and nonhardened (NH^, NHj) 

 cabbages and preserved in 85 per cent alcohol with the addition of 0.5 

 gm. of calcium carbonate. The weights given in grams in Table V express 

 percentages on the basis of green weight. 



Table V. — Complete analyses of hardened and nonhardened cabbages 



Constituent. 



Total solids. ...'... 



Moisture 



Total phosphorus. 

 Total nitrogen . . . . 



10. 1044 



89. 8186 



. 0669 



•3015 



10. 5604 



89. 4396 



. 0664 



.3024 



90 



Total lipoid phosphorus. 

 Total lipoid nitrogen. .. . 



0124 

 0112 



, 0121 

 . 0129 



Organic solids F2 



Phosphorus Fj 



Nitrogen Fj 



Ammonia Fj 



Total Van Slyke nitrogen. 



I- 5037 

 . 0023 



, 0010 

 ,0168 



I. 6137 



•044S 

 . 0162 



Organic solids 



Phosphorus F3 



Nitrogen F3 



Water-soluble phosphorus F3. 



5. 8603 

 .0522 



6. 0869 

 • 0520 

 .2458 

 .0314 



035 

 965 

 0535 

 2986 



0146 



0859 

 0029 



0459 

 0007 

 0084 



8756 

 0417 

 2381 

 0265 



2945 

 965 

 0537 

 2915 



0093 

 0123 



2750 

 0041 

 0464 



0068 



0593 

 0403 

 2328 



The percentage of moisture in hardened cabbages is decreased slightly 

 with a corresponding increase in the organic solids of the third fraction 

 (F3). It is difficult to obtain the same degree of humidity under such 

 different conditions as used for hardening, and this may well account for 

 a difference of i per cent of moisture, as shown here. In the hardened 

 plants the increase in total nitrogen and phosphorus is noticeable. The 

 increase in phosphorus is in accord with the finding of greater amounts 

 of calcium malophosphate in hardened plants by microchemical means. 



The increase in the aminonitrogen of hardened plants is suggestive of 

 the changes which occur in the proteins. Schaffnit (44) found the pro- 

 teins from hardened plants to be more difficult to precipitate by freezing 

 than those from greenhouse plants. He ascribed this to changes in the 

 proteins resulting in the cleavage of the more labile "high molecular" 

 forms. According to the above analyses, the aminonitrogen represents 

 35 per cent of the total nitrogen of the second fraction (Fj) in the hardened 

 cabbages and about half that amount in the nonhardened plants, or 5.5 

 per cent of the total nitrogen in the first case and 2.5 per cent in the second 

 case. Although this is a small change, it is not necessary nor probable 

 that cleavage as far as to the amino acids should occur to prevent precipi- 

 tation on freezing. 



