ISSN:
1432-2285
Schlagwort(e):
Chalcone synthase
;
Juglans sp.
;
Rejuvenation
;
Phenylalanine ammonia lyase
;
Polyphenolic compounds
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
,
Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
Notizen:
Summary During the first growth phase of walnut (Juglans sp.) stump shoots, the concentrations of the two major phenolic compounds are not correlated with an increasing rate of shoot growth. The concentration of hydrojuglone glucoside (naphtoquinone) decreases as shoot growth rate increases, whereas the concentration of myricitrin (flavonol) remains constant. In contrast, phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activity is proportional to the growth rate of shoots. Rejuvenation, which induces a higher growth rate and vegetative propagation ability, results in an increase of both PAL and chalcone synthase (CHS, EC 2.3.1.74) activities and hydrojuglone glucoside/myricitrin ratio. Moreover, physiological ageing is characterized by an accelerated functioning of polyphenolic metabolism. Fluctuations in PAL activity are associated with changes in shoot growth rate and with rejuvenation, but PAL does not directly control the accumulation of flavonoid compounds during rejuvenation. On the contrary, mathematical correlation of CHS activity and flavonoid accumulation during annual shoot growth of both adult and rejuvenated trees, indicates that CHS is the rate-limiting enzyme of the pathway.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00225475
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