Roots of Higher Plants

Stimulation of the growth of isolated roots of higher plants has been observed (see Table X). It would appear that pyridoxin is normally synthesized in the green leaf and transmitted to the roots (313). The specificity of pyridoxin in isolated root growth (300) is analogous to the specificity in the growth response for other types of organism (see Table XI). 

---

P. M. West, Excretion of thiamin and biotin by the roots of higher plants. Nature (London) /44 1050 (1939). 

Vaughan, D., and Malcolm, R. E. (1979a). Effect of humic acid on invertase synthesis in roots of higher plants. Soil Biol. Biochem. 11, 247-272. 

BNF is a microbially mediated process that occurs in several types of bacteria and blue-green algae. This process uses the enzyme nitrogenase in an anaerobic environment to convert N2 to NH3. The microbes can be free-living or in a symbiotic association with the roots of higher plants. Legumes are the best-known example of this type of relationship (Schlesinger, 1997 Mackenzie, 1998) ... 

Many species of fungus grow in a close association with the roots of higher plants, in a mutualistic symbiosis known as a mycorrhiza. The mycorrhizal mutualism is very important to the uutritiou of the plant, because of the greatly enhanced access to uutrieuts that is provided, particularly to phosphate. 

Rhi zoids.—Absorptive organs of certain plants below the Pteridophytes that are analagous with roots of higher plants. 

The ultimate process by which organic esters are made available in inorganic form (mineralisation) is by phosphatase enzymes, which are produced by the roots of higher plants and numerous microorganisms (12.14). 

C. are synthesized mainly in the roots of higher plants and they are not subject to much translocation. It is interesting that they occur in certain transfer RNA molecules 0.05 to 0.1 % of the purine bases in tRNA have cytokinin activity. In E. coli, the tRNA species for phenylalanine, leucine, serine, tyrosine and tryptophan contain C. N -(y,y -dimethylallyl)-Adenosine (see) also occurs in the free form. The most important C. are Kinetin (see), Zeatin (see) and Dihydrozeatin (see). The synthetic C, A-benzyl-adenine (see 6-Benzylaminopurine) and SD 8339 (Fig. 2) also have high cytokinin activity. 

Adenylated thiamin derivatives have only been recently discovered (Bettendorff et al. 2007 Frederich et al. 2009). AThTP is foimd in several tissues (mammalian liver and heart, roots of higher plants, etc. but it is not as widespread as ThTP. It is very often found in cultured cells. In E. coli, it is produced in response to carbon starvation and may reach up to 15% of total thiamin (Gigliobianco et al. 2010). AThDP was only found in low amounts in rodent liver and in E. coli. 

VAUGHAN D. and MALCOLM R.E. 1979. synthesis in roots of higher plants... 

The accumulation of lycopene in place of cyclic carotenoids has also been observed in a number of fruits, including citrus fruits, in roots of higher plants, and in fungi. ... 

Thiamin in the Growth of Isolated Roots of Higher Plants. . . 124... 

A. Thiamin (vitamin Bi) Higher animab Bacteria lower fungi, pro-tosoa, roots of higher plants Co-carboiylase thiamin —protein enzsrmes... 

The picture of the ways in which thiamin is related to bacterial growth is paralleled with other types of organism. In particular, molds, lower fungi, protozoa (118) and the isolated roots of higher plants have been extensively examined. A collection of the observations illustrating the parallelism with the bacterial findings is given in Tables III, IV, and V. 

---