20 EXPERIMENT STATION RECORD. 



Distilled water was found to become alkaline very generally if allowed to remain 

 on the leaves of plants for a considerable time. Certain plants which are adapted to 

 growth in moist climates may be made to take in all the food necessary for growth 

 through the leaves. Distilled water used as a spray may for a time act as a stimu- 

 lant to plant growth. This action may probably be due to the fact that it draws 

 from the plant the surplus alkaline salts which, if too abundant in the cells, might 

 become harmful. Rain water probably acts as a stimulus in the same way. 



Solutions applied t<> the surface of detached leaves, or leaves still upon the plant, 

 are generally absorbed, as shown by the increased content of ash. When so applied 

 the solutions often stimulate a portion of the leaf to abnormal development, produc- 

 ing a ring upon the leaf by the peculiar action of the evaporating drop. When 

 applied to the cut ends of the petioles of leaves, solutions generally kill the tissue at 

 the termination of the tracheids, either by withdrawing the water from the inter- 

 cellular spaces or by chemical action upon the walls of the cells or on the cell con- 

 tents. The first determinable reaction after the death of the tissues is alkaline, even 

 though the tissues themselves may be killed by an acid. 



In the experiments reported it was found that substances in solution frequently 

 ascend through the blade of the leaf at a rate which varies with the length of the 

 different veins of the leaf. The lithium test, frequently used to determine the ascent 

 of the liquid through plants, is often a source of error, a< the water ascends faster 

 than the salt in solution. 



Experiments with woody branches of willows showed that the food required for 

 the early spring growth of this shrub was water, and that nutrient solutions at this 

 stage proved harmful. Water and other solutions applied to the twigs showed that 

 they were not absorbed through the bark, but the indications showed that the 

 absorption takes place through the buds. 



Experiments with sea water showed that the effect produced upon the atmosphere 

 results in an accumulation of rust upon iron greater than that produced upon the 

 atmosphere under the influence of pure water; and it is concluded from this that a 

 similar physiological process accompanying the chemical process may result with 

 plants growing in the vicinity of the sea. 



On account of the economic importance of the subject, the author devotes a con- 

 siderable portion of the paper to the physiological effect of some of the constituents 

 of Bordeaux mixture when used as a fungicide, and some of the causes of natural and 

 artificial spotting of tobacco. The paper concludes with a bibliography of some of 

 the more important work dealing with this subject. 



The physiological action of iodin and fluorin compounds on agricultural 

 plants, S. Suzcki and K. Aso (Bui. Col. Ayr., Tokyo Imp. Univ., 5 (190.1), Xo. .}, pp. 

 47-1-479, pi. 1). — The authors having determined that potassium iodid in exceedingly 

 high dilution exerted a stimulating effect on various plants, conducted experiments 

 with this and sodium fluorid on a number of economic plants. With oats and 

 radishes the stimulating effect of these chemicals was cpiite evident and the increased 

 crop was made at a correspondingly very small cost. 



In commenting upon the effect of potassium iodid the authors state that the sub- 

 stitution of the crude ash of seaweeds would probably be the most economical way of 

 securing the iodid. Attention is called to the fact that farmers along the coast of 

 Japan apply seaweeds as a green manure with very great success, and it is probable 

 that this success is due not only to the small quantities of potash, nitrogen, and 

 phosphoric acid, but also to the small quantity of- iodin present. 



The physiological effect of rubidium chlorid on plants, 0. Loew ( Ihil. Col. 

 Agr., Tokyo Imp. Univ., 5 I 1903), No. 4. pp. 461-40.5, pi. 1). — Pot experiments with 

 Chinese cabbage, barley, and spinach are reported in which the effect of rubidium 

 chlorid was tested. Where the chemical was added in amounts not to exceed 10 nig. 

 per 50 kg. of soil a stimulating effect was noted, the treated plants being larger and 

 the fresh and dry weights greater in nearly every instance. When applied at the 



