Changes in Carbohydrate and ABA Content during GA-induced Growth of Non-cooled Tulip Bulbs

Tulip bulbs (Tulipa fosteriana, L.) contain peroxidases catalyzing the oxidation of the xenobiotics N-nitrosodimethylamine (NDMA) and N-nitroso-N-methylaniline (NMA). Three anionic (A1, A2, A3) and four cationic (B, C, D, E) peroxidases were purified from this tissue, partially characterized and used for kinetic studies. Demethylation of NDMA and NMA producing formaldehyde is catalyzed by one anionic (A1) and three cationic (C, D, E) peroxidases. The oxidation of NDMA by tulip peroxidases exhibits the Michaelis-Menten kinetics. The apparent Michaelis constant and the maximal velocity values for this substrate were determined. On the other hand, non-Michaelian kinetics for the NMA oxidation were observed with tulip peroxidases. The most abundant cationic peroxidase (peroxidase C) was used for detailed enzymatic studies. In addition to formation of formaldehyde, methylaniline, aniline, 4-aminophenol and phenol were found to be metabolites formed from NMA. Phenol was formed presumably by N-demethylation via a benzenediazonium ion, while methylaniline, aniline and 4-aminophenol were products of denitrosation of the substrate. The efficiencies of plant peroxidases to oxidize NDMA and NMA in vitro are compared with those of cytochromes P450 and discussed.

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Interplay among Antioxidant System, Hormone Profile and Carbohydrate Metabolism during Bud Dormancy Breaking in a High-Chill Peach Variety

Antioxidants ◽

10.3390/antiox10040560 ◽

2021 ◽

Vol 10 (4) ◽

pp. 560

Author(s):

José A. Hernández ◽

Pedro Díaz-Vivancos ◽

José Ramón Acosta-Motos ◽

Nuria Alburquerque ◽

Domingo Martínez ◽

...

Keyword(s):

Starch Content ◽

Sugar Metabolism ◽

Bud Dormancy ◽

Dormancy Breaking ◽

Prunus Species ◽

Physiological Factors ◽

Antioxidant Metabolism ◽

Hormone Profile ◽

Aba Content ◽

Gas Ratio

(1) Background: Prunus species have the ability to suspend (induce dormancy) and restart growth, in an intricate process in which environmental and physiological factors interact. (2) Methods: In this work, we studied the evolution of sugars, antioxidant metabolism, and abscisic acid (ABA) and gibberellins (GAs) levels during bud dormancy evolution in a high-chill peach variety, grown for two seasons in two different geographical areas with different annual media temperature, a cold (CA) and a temperate area (TA). (3) Results: In both areas, starch content reached a peak at ecodormancy, and then decreased at dormancy release (DR). Sorbitol and sucrose declined at DR, mainly in the CA. In contrast, glucose and fructose levels progressively rose until DR. A decline in ascorbate peroxidase, dehydroascorbate reductase, superoxide dismutase and catalase activities occurred in both seasons at DR. Moreover, the H2O2-sensitive SOD isoenzymes, Fe-SOD and Cu,Zn-SOD, and two novel peroxidase isoenzymes, were detected. Overall, these results suggest the occurrence of a controlled oxidative stress during DR. GA7 was the major bioactive GA in both areas, the evolution of its levels being different between seasons and areas. In contrast, ABA content decreased during the dormancy period in both areas, resulting in a reduction in the ABA/total GAs ratio, being more evident in the CA. (4) Conclusion: A possible interaction sugars-hormones-ROS could take place in high-chill peach buds, favoring the DR process, suggesting that, in addition to sugar metabolism, redox interactions can govern bud DR, regardless of chilling requirements.

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Regulation of Flowering Timing by ABA-NnSnRK1 Signaling Pathway in Lotus

International Journal of Molecular Sciences ◽

10.3390/ijms22083932 ◽

2021 ◽

Vol 22 (8) ◽

pp. 3932

Author(s):

Jing Cao ◽

Qijiang Jin ◽

Jiaying Kuang ◽

Yanjie Wang ◽

Yingchun Xu

Keyword(s):

Protein Kinase ◽

Environmental Changes ◽

Molecular Genetic ◽

Maximal Response ◽

Protein Kinase Activity ◽

Hormonal Changes ◽

Flower Buds ◽

Flower Bud ◽

Aba Content ◽

Flower Bud Abortion

The lotus produces flower buds at each node, yet most of them are aborted because of unfavorable environmental changes and the mechanism remains unclear. In this work, we proposed a potential novel pathway for ABA-mediated flower timing control in the lotus, which was explored by combining molecular, genetic, transcriptomic, biochemical, and pharmacologic approaches. We found that the aborting flower buds experienced extensive programmed cell death (PCD). The hormonal changes between the normal and aborting flower buds were dominated by abscisic acid (ABA). Seedlings treated with increasing concentrations of ABA exhibited a differential alleviating effect on flower bud abortion, with a maximal response at 80 μM. Transcriptome analysis further confirmed the changes of ABA content and the occurrence of PCD, and indicated the importance of PCD-related SNF1-related protein kinase 1 (NnSnRK1). The NnSnRK1-silenced lotus seedlings showed stronger flowering ability, with their flower:leaf ratio increased by 40%. When seedlings were treated with ABA, the expression level and protein kinase activity of NnSnRK1 significantly decreased. The phenotype of NnSnRK1-silenced seedlings could also be enhanced by ABA treatment and reversed by tungstate treatment. These results suggested that the decline of ABA content in lotus flower buds released its repression of NnSnRK1, which then initiated flower bud abortion.

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Influence of the extent and duration of cold treatment on the flowering behaviour, composition and metabolic activity of tulip bulbs

Scientia Horticulturae ◽

10.1016/0304-4238(78)90035-3 ◽

1978 ◽

Vol 8 (3) ◽

pp. 279-287 ◽

Cited By ~ 4

Author(s):

G.E. Hobson ◽

J.N. Davies

Keyword(s):

Metabolic Activity ◽

Cold Treatment ◽

Flowering Behaviour ◽

Tulip Bulbs

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Different amounts of cytochrome P-450 dependent monooxygenases in tulip bulbs, pea seedlings and maize endosperm cells

Plant Science ◽

10.1016/0168-9452(94)90170-8 ◽

1994 ◽

Vol 99 (2) ◽

pp. 135-140 ◽

Cited By ~ 5

Author(s):

Laura Marabini ◽

Sonia Radice ◽

Barbara Cipelletti ◽

Enzo Chiesara

Keyword(s):

Maize Endosperm ◽

Pea Seedlings ◽

Tulip Bulbs ◽

Cytochrome P 450

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Purification of a single major form of microsomal cytochrome P-450 from tulip bulbs (Tulipa gesneriana L.).

Agricultural and Biological Chemistry ◽

10.1271/bbb1961.49.2399 ◽

1985 ◽

Vol 49 (8) ◽

pp. 2399-2405 ◽

Cited By ~ 26

Author(s):

Ken HIGASHI ◽

Kie IKEUCHI ◽

Masanobu OBARA ◽

Yuji KARASAKI ◽

Hideyasu HIRANO ◽

...

Keyword(s):

Tulipa Gesneriana ◽

Microsomal Cytochrome ◽

Major Form ◽

Tulip Bulbs ◽

Cytochrome P 450

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Effects of Cultivar and Ethanol Disinfection on Aseptic Germination of Loquat (Eriobotrya japonica) Seeds

HortScience ◽

10.21273/hortsci11979-17 ◽

2017 ◽

Vol 52 (7) ◽

pp. 941-945

Author(s):

Kunkun Li ◽

Weiqi Dong ◽

Yun Zhao ◽

Hongxia Xu ◽

Junwei Chen ◽

...

Keyword(s):

Detrimental Effect ◽

Germination Rate ◽

Fruit Tree ◽

Final Concentration ◽

Eriobotrya Japonica ◽

Seedling Height ◽

Disinfection Procedure ◽

Aba Content ◽

Subtropical Fruit ◽

The Relationship

Loquat (Eriobotrya japonica Lindl.) is an economically important subtropical fruit tree, originating and commercially produced mainly in China and Japan. The aseptic seed germination of 13 loquat cultivars, including 9 white-fleshed cultivars and 4 red-fleshed ones, was studied, and the relationship between the germination rate and the content of endogenous ABA in seeds was explored. The germination rate and the seedling height at 80 days after sowing of white-fleshed cultivars were generally higher than that of red-fleshed ones. The ABA content in seeds was generally lower in white-fleshed cultivars, and the ABA content negatively correlated with the germination rate at 80 days after sowing. A moderate detrimental effect of 75% ethanol disinfection on aseptic germination of loquat seeds was observed, especially, for the cultivar Dahongpao, and the germination rate and seedling height were reduced by around half and one-third, respectively. The addition of plant preservative mixture (PPM) to the germination medium at a final concentration of 25 mg·L−1 effectively controlled contamination when the 75% ethanol disinfection procedure was omitted.

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