XI. THE PLANT 233 



nitrogen and sulphur from their oxidised compounds. 1 Experiments 

 made recently, especially in Japan, show that barley, French beans 

 and potatoes are able to produce proteids from nitrates in complete 

 darkness, provided they be supplied with a sufficient amount of sugar ; 

 with small quantities of sugar no proteids were formed. Hence the 

 necessity of light in proteid formation really depends upon the pro- 

 duction of abundance of carbohydrates. Asparagine is probably an 

 intermediate product between nitrates and proteids and accumulates 

 in the plant if the conditions for proteid production are not favourable. 2 

 Since asparagine seems undoubtedly to be produced from proteids 

 when translocation of nitrogenous matter takes place, it appears that 

 amides are products both of anabolism and katabolism. 3 It has been 

 shown that in many plants the leaves cut in the morning contain much 

 less starch and nitrogenous material than similar leaves cut in the 

 evening, proving that during the night there is a transference of starch 

 and albuminoids stored during the day in the leaves, to other parts of 

 the plant. 4 



The Flowers and Seeds. The formation of flowers and seeds is 

 a process which, in many plants, is the final act of their vitality. Dur- 

 ing flowering, true respiration, -i.e., oxidation of carbonaceous matter 

 and evolution of carbon dioxide, takes place more rapidly than usual, 

 and in some cases to an extent sufficient to bring about a sensible rise 

 of temperature. It must be remembered that respiration goes on 

 during the whole of a plant's active existence, but during daylight is 

 more than counterbalanced by the assimilative process already described. 



In certain plants biennials preparation for tke great work of 

 seed formation occupies the whole of their first year's life. A large 

 store of reserve material is accumulated, either in the root or stem, 

 and during the second year this is utilised in the production of a flower 

 stem and seeds. 



During the formation of seed a concentration of nutritive matter 

 from the stem, root and foliage into the seed takes place, and the 

 main portions of the plant are thus robbed of most of their important 

 constituents. In many plants the maximum amounts of nutritive 

 matters are found in the leaves, stems, etc., immediately before 

 flowering. 



A store of food material, intended for the nourishment of a new 

 plant, accumulates in the seed. Albuminoids are always present, 

 together with phosphorus, sulphur, potassium, chlorine and the other 

 elements essential to plant life. Of carbonaceous matter, however, 

 two varieties occur. Some seeds contain large amounts of carbo- 

 hydrates, chiefly starch, while others are practically devoid of starch, 

 but contain fats or oils in large proportion. 



^odlewski, Jour. Chem. Soc., 1897, Abstracts, ii. 583. 



? Kinoshita, Jour. Chem. Soc., 1896, Abstracts, ii. 54 ; Suzuki, Jour. Chem. 

 Soc., 1899, Abstracts, ii. 323. 



3 Vide Wassilieff, Ber. deut. botan. Gesell., 1908; Jour. Chem. Soc., 1908, Ab- 

 stracts, ii. 1976, and Scurti and Parrozzini, Gazzetta, 1908, 216 ; Jour. Chem. Soc., 

 1908, Abstracts, ii. 417. 



4 Suzuki, Jour. Chem. Soc., 1897, Abstracts, ii. 580. 



