ARRHIZA — THE SMALLEST WITH THE HIGHEST ADAPTATION ABILITY AND APPLICATIONS Summary

Wolffia arrhiza from the Lemnaceae genus is rion and a variety of compounds. Biochemi- the smallest , which is very expansive cal analysis revealed the occurrence of high level of and reproduces intensively by gemmation under cyanocobalamin (vitamin B12) and hormones, steroid conditions of our climate. In Polish waters it is be- principally. Therefore it can be used as cattle fod- coming more and more abundant, especially in small der rich in proteins, , vitamins, hormones and and shallow eutrophic reservoirs, rich in organic mineral salts. W. arrhiza also may be taken advan- substances. The W. arrhiza’s morphological and ana- tage of in biotechnology to obtain biologically active tomical structure underwent a high simplification compounds important for dietetics, phytotherapy process due to adaptation to the specific environ- and phytocosmetics. ment conditions. The atypical leaf-like body, called The examination of the effect of some phyto- a frond, is a complex of tissues with only little dif- hormones on W. arrhiza metabolism shows that the ferentiation, therefore the W. arrhiza’s organism re- plant reacts atypically to phytohormones, in com- sembles more the thallophytic algae than vascular parison with other vascular and algae from plants. In unfavourable environmental conditions, es- Chlorophyceae which is probably due to its hetero- pecially in the winter and autumn, the frond chang- trophic properties. Of auxins, the PAA (chemical an- es to a resting form, which is called a turion. The alogue of IAA) was observed to have the most stim- plant is very resistant to the impact of various stress ulating activity as compared with other IAA-treated and toxic factors such as: temperature and pH fluc- plants. Salicylic acid also showed a strong effect on tuations, xenobiotic pollution. In environment rich the plant growth, accumulation of organic compo- in organic substances, W. arrhiza changes a way of nents and net photosynthetic rate. The cytokinins, feeding from photoautotrophic into heterotrophic. derivatives of adenine and urea, were found to have Due to these properties, the plant is used more and a stimulating effect on the growth and metabolism more commonly in biotechnology of sewage treat- of W. arrhiza with varying intensity which can be ment especially of municipal, agricultural and dairy explained by the large difference in their chemical origin, rich in aminoacids, proteins, sugars, organic structure. From among steroid hormones tested, β- nitrogen and phosphorus compounds. The wastes estradiol and testosterone were shown to have the to which W. arrhiza’s culture become more easily most stimulating effect on the growth, and content clarified, the values of BOD5, COD and organic com- of nucleic acids and protein. On the other hand, the pounds contents are reduced. accumulation of monosaccharides was observed un- The W. arrhiza’s biomass is characterised by der the influence of corticosteroids: cortisone, 11- high accumulation of proteins (40–50%) in vegeta- deoxycorticosterone and cortisole, this being analog- tive form (frond), the same amount of starch in tu- ical to the effect of these hormones on animal cells.