Topic
Zeatin
About: Zeatin is a research topic. Over the lifetime, 2467 publications have been published within this topic receiving 64092 citations. The topic is also known as: Zeatin & (E/Z)-zeatin.
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TL;DR: Lupinic acid (III), a metabolite of the phytohormone zeatin (I), was synthesized from O-acetyl-L-serine (II) and Zeatin by an enzyme in higher plants as mentioned in this paper.
Abstract: Lupinic acid (III), a metabolite of the phytohormone zeatin (I), was synthesized from O-acetyl-L-serine (II) and zeatin by an enzyme in higher plants. Some properties of the enzyme are described.
22 citations
TL;DR: Modifications in the hormonal balance and the perturbation of the meristematic activity on the clinostat were followed by a loss of apical dominance, which was responsible for the early initiation of secondary roots, the greater elongations of the root system and the emergence of the lateral roots near the tip of the primary root.
Abstract: The morphometry of the root system, the meristematic activity and the level of indole-3-acetic acid (IAA), abscisic acid (ABA) and zeatin in the primary root tips of rapeseed seedlings were analyzed as functions of time on a slowly rotating clinostat (1 rpm) or in the vertical controls (1 rpm). The fresh weight of the root system was 30% higher throughout the growth period (25 days) in clinorotated seedlings. Morphometric analysis showed that the increase in biomass on the clinostat was due to greater primary root growth, earlier initiation and greater elongation of the secondary roots, which could be observed even in 5-day-old seedlings. However, after 15 days, the growth of the primary root slowed on the clinostat, whereas secondary roots still grew faster in clinorotated plants than in the controls. At this time, the secondary roots began to be initiated closer to the root tip on the clinostat than in the control. Analysis of the meristematic activity and determination of the levels in IAA, ABA and zeatin in the primary root tips demonstrated that after 5 days on the clinostat, the increased length of the primary root could be the consequence of higher meristematic activity and coincided with an increase in both IAA and ABA concentrations. After 15 days on the clinostat, a marked increase in IAA, ABA and zeatin, which probably reached supraoptimal levels, seems to cause a progressive disturbance of the meristematic cells, inducing a decrease of primary root growth between 15 and 25 days. These modifications in the hormonal balance and the perturbation of the meristematic activity on the clinostat were followed by a loss of apical dominance, which was responsible for the early initiation of secondary roots, the greater elongation of the root system and the emergence of the lateral roots near the tip of the primary root.
22 citations
TL;DR: A bioassay is proposed based upon two different effects of cytokinins on barley during its germination, which results in a barley cytokinin which resembles zeatin riboside being isolated and quantitatively determined from 3-day-old barley seedlings.
22 citations
TL;DR: Oncidium cultivars gave different embryogenic responses of leaf explants when affected by auxins (2,4-D, IAA, IBA and NAA), cytokinins, sucrose, NaH2PO4, casein hydrolysate, peptone, and glutamine, which affected the development of somatic embryos of cv.
Abstract: Oncidium cultivars gave different embryogenic responses of leaf explants when affected by auxins (2,4-D, IAA, IBA and NAA), cytokinins (2iP, BA, kinetin, TDZ and zeatin), sucrose, NaH2PO4, casein hydrolysate, peptone, and glutamine. The best embryogenic responses of cv. Sweet Sugar were at 20 g dm−3 sucrose, 85 mg dm−3 NaH2PO4 and 3 mg dm−3 kinetin, respectively. The development of somatic embryos on leaf explants of cv. Sweet Sugar was delayed for about 10 – 20 d in comparison with cv. Gower Ramsey. On growth regulator-free medium, about 40 % of leaf derived embryos of cv. Gower Ramsey were fused together in their basal parts and so called multiple-state embryos. However, under the same condition, the embryos of cv. Sweet Sugar were all in multiple-state form.
22 citations
TL;DR: It is proposed that the balances of Cks/IAA and iP-type/Z-type Cks are good indices of different developmentalstates in Prunus persica.
Abstract: Prunus persica plants of different ages and statesof maturation were analysed to compare their phytohormonal status Endogenouslevels of indole-3-acetic acid (IAA), abscisic acid (ABA), and severalcytokinins (Cks): zeatin (Z), zeatin riboside ([9R]Z), dihydrozeatin ((diH)Z),dihydrozeatin riboside ((diH)Z[9R]), isopentenyl adenine (iP) and isopentenyladenosine ([9R]iP), were measured in order to determine their possible use asphysiological indices of phase change and maturation A decrease in Ck levels(Z, [9R]Z, (diH)Z, (diH)[9R]Z, and iP, [9RiP) was found from the embryonic tojuvenile stage as well as a decrease in the ratio of iP-type (iP and[9R]iP)/Z-type Cks paralleling the increase in tree age ABA levels increasedduring maturation in Prunus persica and the ratio ofCks/IAA decreased with tree age From our results, we propose that the balancesof Cks/IAA and iP-type/Z-type Cks are good indices of different developmentalstates in Prunus persica
22 citations