Production of phenolic compounds in callus cultures of tea plant under the effect of 2,4-D and NAA

The effect of hormone-like compounds at different concentrations: 2,4-D (2 × 10^?6; 2 × 10^?5; and 2 × 10^?4M) and 1-NAA (2 × 10^?7; 2 × 10^?6; 2 × 10^?5; 4 × 10^?5, and 6 × 10^?5 M) on the growth and production of phenolic compounds, including flavans and lignin, was investigated in callus culture of tea plant (Camellia sinensis L., a highly productive strain IFR ChS-2). The growth of the culture was vigorous, and production of phenolic compounds therein was efficient in the medium containing 2 × 10^?5 M 2,4-D. Substitution of 1-NAA for 2,4-D in all the cases decelerated the growth of the culture. These changes were more pronounced when 2 × 10^?7 and 2 × 10^?6 M 1-NAA was used; in this case, biomass accumulation decreased by 1.5–2.0 times as compared with control material growing on the medium with 2 × 10^?5 M 2,4-D. In the presence of 1-NAA, the content of total soluble phenolic compounds and flavans in the calli rose by 30% on the average as compared with control material. Accumulation of lignin remained essentially the same. Therefore, the replacement of 2,4-D with 1-NAA in the nutrient medium used for the growing of highly productive strain of tea plant callus did not induce considerable changes in its ability to produce phenolic compounds.     

Andrei L'vovich Kursanov (1902–1999)

Russian Journal of Plant Physiology -     

Heterogeneity of molecular forms of phenol oxidase from apple fruits]

Qualitative differences of a dimer (m.w. 60.000-70.000) and a monomer (m.w. 30.000-40.000) fractions of phenoloxidase (EC 1.10.3.1), isolated from fruits of two winter varieties of apples were studied. tthe fractions analysed differed markedly in their Km values and the Hill coefficients. The monomer fraction possessed a higher affinity for monophenols and is capable to accomplish the hydroxylation reaction more actively. The interrelation of these changes and the aging of fruits under storage conditions with resulting changes in their total metabolism is discussed.     

Biosynthesis of beta-phenylethanol in rose petals]

Biosynthesis of beta-phenylethanol is studied in a cell-free rose petals extract. This compound found to be synthesized via two intermediates: either trans-cinnamic acid, or phenylacetaldehyde. Subsequently beta-phenylethanol is glucosodized into its transport form, beta-phenylethanol- beta-D-glucoside. A scheme of beta-phenylethanol and its beta-D-glucoside is given.     

Chloroplasts Isolated from Kidney Bean Leaves Are Capable of Phenolic Compound Biosynthesis

The homogenate and chloroplast fractions isolated from the leaves of 10–14-day-old kidney-bean (Phaseolus vulgaris L.) seedlings were incubated with ¹⁴C-L-phenylalanine for 30 min in the light, and the incorporation of radioactivity into phenolic compounds was determined. Label incorporation into phenolic compounds of the homogenate and chloroplast fractions amounted to 15–17 and 4–5% of the introduced radioactivity, respectively. The chloroplasts were about an order of magnitude higher than the homogenate in the specific radioactivity of phenolic compounds. Chloroplasts contained four flavonol glycosides (kaempferol and quercetin aglycones), which were the major components of soluble phenolic compounds of leaves. It was concluded that kidney-bean leaf chloroplasts were capable of performing phenolic compound biosynthesis.     

Heterogeneity of molecular forms of phenol oxidase from grape leaves

The substrate specificity and some kinetic properties of the monomeric (Mr = 26 000--35 000) and dimeric (Mr = 55 000--70 000) forms of phenol oxidase from vine leaves were studied. These forms possess different hydroxylating and o-diphenol oxidase activities. A kinetic analysis demonstrated that the monomeric form of the enzyme possesses a higher affinity for monophenols and can more effectively accomplish the hydroxylation reaction as compared to the dimeric one. During vine vegetation the ratio of molecular forms of phenol oxidase is altered manifesting itself in quantitative and qualitative changes of enzymatic activity. During plant maturation the dimeric fraction is predominant. The maturation process is associated with a sharp rise of the o-phenol oxidase activity, a disappearance of the hydroxylating activity and a substantial deceleration of phenol compounds production.     

Interrelationship between glucoside-bound and free alcohols during ether oil formation in rose petals]

Some data on the dynamics of free and glucoside-bound monoterpenic and aromatic (beta-phenylethyl) ethers content and the changes in the beta-glucosidase activity in rose petals at different stages of the flower development and on the kinetics of enzymatic hydrolysis of these glucosides are presented. The phase specificity of beta-glucosidase coinciding with the maximal accumulation of glucoside-bound and free alcohols is revealed. The data obtained suggest that the formation of glucosides may precede the accumulation of corresponding free alcohols of terpenic and aromatic origin.