The Tanada effect refers to the

adhesion Adhesion is the tendency of dissimilar particles or surfaces to cling to one another ( cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another). The forces that cause adhesion and cohesion can b ...

root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the su ...

tips to

glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling ( quenching ...

surfaces. It is believed to involve

electric Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by ...

potentials. It is named for the

scientist A scientist is a person who conducts scientific research to advance knowledge in an area of the natural sciences. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engaged in the philosoph ...

who first described the effect, Takuma Tanada. The phenomenon was observed while Dr. Tanada was rinsing glassware and noticed that excised root tips occasionally stuck to pyrex beakers. Upon investigating the phenomenon closely he determined that this process could be studied in a mixture of ATP, ascorbate, auxin,

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

and

potassium Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosph ...

. The tips would stick when the beaker was swirled slowly. Most importantly, the reaction was light-dependent. Exposure to red light would cause the tips to stick, while exposure to far-red would allow them to release. This simple experiment was indicative of phytochrome function, and the rapid nature of the response suggested that changes in bioelectric potential were seminal events in

phytochrome Phytochromes are a class of photoreceptor in plants, bacteria and fungi used to detect light. They are sensitive to light in the red and far-red region of the visible spectrum and can be classed as either Type I, which are activated by far-re ...

signal propagation. Root tips stick to glass surfaces because they acquire a positive electrostatic charge due to some unknown effect from exposure to red light. The glass surface has a negative charge due to adsorbed

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...

ions. The opposite charges attract each other. This phenomenon is the first reported generation of a bioelectric potential by a photomorphogenic pigment. Several years later, Dr. TanadaTanada, T. "Boron – key element in the actions of Phytochrome and gravity?" ''Planta'' 143:111 (1978) found that the electric charge is generated by the trace element boron. Root tips from plants deficient in boron fail to stick to glass. In a dilute solution of

boric acid Boric acid, more specifically orthoboric acid, is a compound of boron, oxygen, and hydrogen with formula . It may also be called hydrogen borate or boracic acid. It is usually encountered as colorless crystals or a white powder, that dissolve ...

, these tips gradually stick to the glass.

References

{{DEFAULTSORT:Tanada Effect Glass physics Auxin action