922 EXPERIMENT STATION RECORD. 



Movement of plant food before the fall of the leaf, B. RAMANN 

 (Ztschr. Forsf n. J<i(/(hc, :;() (lSf)S), No. .-;, p. ir,~; abs. in Gard. Ghron., 

 .','. ser., :.' i ( 1898), ZVo. 610, pp. 183, 184). — The author states that previous 

 investigations od this subject have usually been undertaken with beech 

 leaves, which are extremely liable to variation in structure and compo- 

 sition iu proportion to the amount of light they receive. In order that 

 his results might admit of comparison with those of other investigators, 

 his experiments were conducted with leaves of beech, oak, hornbeam, 

 and hazel, (riven quantities of the leaves of these species were col- 

 lected at stated periods from June to September, weighed, counted, 

 their superficial area, average si/.e, and weight ascertained, and their 

 composition determined by careful analysis. An analysis was also 

 made of the ash of 100,000 sq. cm. of leaf. 



It was ascertained that the soluble mineral substances reached a 

 maximum about the beginning of June and remained unaltered until 

 autumn. This was especially true of potash and nitrogenous matter 

 almost without exception. Phosphoric acid appeared to show a slight 

 increase toward autumn, perhaps the result of separation of insoluble 

 compounds. The insoluble forms, such as lime, either increase until 

 the period of assimilation is finished or they attain a maximum propor- 

 tion, after which they remain stationary, as is the case of silicic acid. 

 No return movement of material could be noticed up to the end of Sep- 

 tember, and as long as assimilation was continued there was no occa- 

 sion for such movement. In November green and autumn-tinted leaves 

 were gathered from the same branches, the tinted leaves still being tur- 

 gescent and showing some trace of chlorophyll. Testing these leaves 

 with iodin showed that the green leaves were still rich in starch, while 

 the yellow ones had little trace. The detailed results of the analyses 

 show that tinted leaves of beech gave a decrease in the phosphoric 

 acid and nitrogenous substances, a strong increase in silicic acid and 

 potash, and a material increase in lime. In the oak phosphoric acid 

 and nitrogenous matter decreased in the tinted leaves, potash remained 

 about the same, while lime and silicic acid were nearly double the 

 quantity found in the green leaves. In tinted leaves of hornbeam there 

 was a decrease of potash, phosphoric acid, and nitrogenous material 

 and a moderate increase in silicic acid. The leaves of the hazel showed 

 the nitrogenous matter strongly decreased, potash slightly reduced in 

 quantity, and phosphoric acid remaining about the same. Lime and 

 silicic acid were greatly increased. 



Summing up the results of his investigations, the author concludes 

 that during the period of growth in the beech and probably other trees, 

 the proportion of mineral substances in the stem and leaves becomes 

 about equal early in the season and remains unaltered until the growing 

 season is finished. Substances which are partly separated in the insolu- 

 ble form gradually increase in the leaves. With the death of the leaves 

 a considerable movement of mineral substances takes place, the nitrog- 



