The hydrion concentration of plant tissues
In previous articles of this series we have given a general survey of the reaction of stem tissues in a number of families (5), a general survey of the tissue reactions throughout the life-periods of the sunflower (1) and of the bean (6), and also an indication of the possible importance of the carbon dioxide content as a factor governing the hydrion concentration of the cell, especially between pH 6"0 and pH 4"0 which is the usual range in plant tissues (2). In the present article we summarise the data obtained during a general survey of selected herbaceous and woody stems, examined at monthly intervals throughout the year.
Acidity of the Medium and Root Production in Coleus
IN order to test the effect which the reaction of the medium has upon root-production by cuttings, experiments have been made during the summers of 1924 and 1925 with Coleus. It is the practice at the Royal Botanic Garden, Edinburgh, to root in cocoa-nut fibre cuttings which require heat. It was found that the fibre gave a reaction of pH 4.5–4.7, and was very strongly buffered, large additions of acid or alkali being necessary to shift the pH appreciably. (The testing was done with the B.D.H. Capillator, the brown colour of the water squeezed from the fibre causing little trouble in the capillary tube.) In view of this marked buffer action, it is not possible to use this natural fibre for experiment, though it is excellent in practice, being of a light texture and holding a good amount of water without becoming sodden. An artificial medium, comparable to the natural fibre in physical state, of which the reaction can be controlled, has yet to be found. Sand, cotton-wool, and glass-wool, with water, and water alone were tried; only the last proved satisfactory. Experiments were accordingly made with tap-water, adjusted to the required pH by the addition of traces of hydrochloric or sulphuric acids or of sodium carbonate, the normal pH of the water being about 7.3. While these results cannot be directly transferred to the case of fibre, owing to the great differences in oxygen supply, they are at least suggestive.
An Internet-based Real-time Heavy Rainfall Display System
A new storm warning system, which can be accessed through the Internet and by cellular phones is described. At the time of a heavy rainfall for disaster prevention, it is important that every resident understand how heavy is that rainfall. A real-time heavy rainfall display system designed for all of Japan provides such information (http://www.disaster-i.net/rain/). In that system values for 1-hour precipitation, 24-hour accumulated precipitation, etc. are displayed at every observatory. Advantages are that not only the latest observations but differences from the historical highest records can be seen. Almost all information is displayed by characters so that users have easy access to the system even when the communication network is crowded. Access date for the six months after the system opened shows that the average daily number of accesses of the top page was 306, and the largest number 3078. The maximum number for daily access to all the pages was about 21,500. This is about 2% of the number obtained on the same day for a similar system operated by the Ministry of Land, Infrastructure and Transport (http://www.river.go.jp/).