450 Journal of Agricultural Research v^oi.v.no. n 



we are still of the opinion that on account of its hardiness under all sorts 

 of conditions this plant would lend itself better than any other to such 

 studies as those herein contemplated, and we hope to take it up again 

 at some future time. 



In thinking over the subject of the translocation of mineral matter 

 during plant growth it occurred to us that it might be of interest to 

 determine the translocation of the mineral matter contained in the seeds 

 and tubers of certain plants during the period of sprouting. Therefore, 

 our present experiments have been confined to the seeds of the garden 

 bean (Phaseohcs vulgaris), com (Zea mays), and to the potato tuber 

 {Solanum tuberosum). Up to this time our work has been confined to 

 the measurement of the translocation of phosphorus, calcium, potassium, 

 magnesium, and siHcon. 



EXPERIMENTS WITH GARDEN BEANS 



The cotyledons of the garden bean were found to contain a considera- 

 ble amount of mineral matter, and the seedlings of this plant are hardy 

 and well adapted to our requirements. The only difficulties experienced 

 in growing these seedlings under the conditions of these experiments 

 were the growth of molds and the attack of the seedling by the damping- 

 off wilt. The bean in this instance was germinated and allowed to grow 

 to maturity at the expense of the food stored in the cotyledons, extreme 

 care being taken that they should receive no mineral food from external 

 sources. We, of course, realized that the growth of any plant in distilled 

 water is more or less abnormal; yet these beans germinated and pro- 

 duced perfect seedlings with well-developed leaves. 



Great difficulty was experienced in keeping down the growth of molds 

 during the process of germination and in preventing the damping-ofif 

 wilt from attacking the seedlings. In order to overcome these difficul- 

 ties, every precaution was taken to sprout and grow these seedlings 

 under aseptic conditions. The distilled water employed was boiled for 

 20 minutes before coming in contact with the beans. The germination 

 and growth of the seedlings were carried out in a dust-proof closet con- 

 structed for that purpose. A framework of wood was made and covered 

 inside and out with cheesecloth, leaving an air space of about 2 inches. 

 During the experiment both layers of the cheesecloth were kept moistened 

 wdth a 50 per cent solution of glycerin and w^ater. This prevented dust 

 and spores from entering the closet ; yet it allowed a free passage of air 

 and light. An opening was made in the side of the closet just large 

 enough to admit the head and shoulders of a man. Over this opening 

 was hung a curtain, so arranged as to exclude dust while working inside 

 and when the closet was closed. 



The seedlings were never allowed to come in contact with glass. The 

 germinations were made in large porcelain evaporating dishes in which 



