Cytokinins in photoperiodic induction of flowering in Chenopodium species

Macháčková, Ivana; Krekule, J.; Eder, Josef Maria; Seidlová, Frideta; Strnad, Miroslav

doi:10.1034/j.1399-3054.1993.870207.x

Cited by 7 publications

(6 citation statements)

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“…If the floral stimulus is strong enough and transmitted regardless of developmental time, then flowering soon after germination might be predicted providing that the SAM was florally competent. With some exceptions, for example Pharbitis nil and Chenopodium amaranthe (Macháčková et al ., 1993), most plants must go through a juvenile‐to‐mature phase before flowering can occur. Here, cdc25 plants were found to have a shortened time to flowering, which must mean that the SAM acquires floral competence more rapidly than in the WT.…”

Section: Discussionmentioning

confidence: 99%

“…Many studies on flower initiation have made use of obligate photoperiodically sensitive plants, enabling floral mechanisms to be studied using treatments that result in either 100% or zero flowering (Bernier, 1988; Macháčková et al ., 1993; Lejeune et al ., 1994; Corbesier et al ., 2004). However, recently even more effort has been devoted to the facultative long‐day plant Arabidopsis thaliana .…”

Section: Introductionmentioning

confidence: 99%

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The fission yeast mitotic activator cdc25 and sucrose induce early flowering synergistically in the day‐neutral Nicotiana tabacum cv. Samsun

et al. 2007

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Here, the tobacco (Nicotiana tabacum) day-neutral (DN) cv. Samsun transformed with the Schizosaccharomyces pombe mitotic activator gene Spcdc25 was used to study the onset of flowering. Wild type (WT) and cdc25 plants were grown from seeds in vitro until they were 20 cm high. Apical and basal nodes were then subcultured repeatedly and the regenerated plants were used to document time to flowering and the number of leaves formed before flowering. Three sucrose treatments (3, 5 or 7% (weight/volume)) were used and measurements of leaf endogenous soluble carbohydrates were performed. In the 3% treatment, cdc25 plants flowered but WT plants did not. The higher sucrose treatments enabled WT flowering; two-thirds of the plants flowered at 5%, while all plants flowered at 7% sucrose. However, in all treatments, cdc25 plants exhibited significantly earlier flowering and fewer leaves compared with wild type. Remarkably, a typical acropetal flowering gradient in WT plants did not occur in cdc25 plants. In cdc25 leaves, there were significantly higher amounts of endogenous sugars with a higher proportion of sucrose compared with WT. Our data demonstrate that Spcdc25 expression and sucrose act synergistically to induce precocious flowering.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The fission yeast mitotic activator cdc25 and sucrose induce early flowering synergistically in the day‐neutral Nicotiana tabacum cv. Samsun

et al. 2007

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“…Cytokinins are known to play a major role in flower initiation (Bernier et al, 1993 ;Machackova et al, 1993) : thus, increased cytokinin concentration might be used by the ice plant as a signal for the developmental progression from the juvenile to the adult and flowering forms. As an hypothesis, we suggest that ABA signalling might not play a role in the plant's initial adaptation to stress, but that ABA serves as an enhancer of gene expression when the plants experience prolonged stress which propels them into the mature growth phase.…”

Section:    - mentioning

confidence: 99%

Growth and development of Mesembryanthemum crystallinum (Aizoaceae)

et al. 1998

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“…Cytokinin contents were determined according to Strnad et al (1989) and Macháčková et al (1993). Briefly, methanolic extracts (80 %) were first purified on P-and DEAE-cellulose columns and then on a SepPak cartridge where CKs caught.…”

Section: Methodsmentioning

confidence: 99%

Extent of ipt gene expression and resulting amount of cytokinins affect activities of carboxylation enzymes in transgenic plants

Květoň¹

2006

Biologia plant.

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Three types of transgenic plants of Solanum tuberosum cvs. Kamýk and Oreb, and Nicotiana tabacum cvs. Maryland Mammoth and Trapezond were selected according to intensity of introduced ipt gene expression and resulting amount of synthesised cytokinins (CKs). In comparison with controls, original transgenic regenerants grown in vitro showed a massive increase of CK contents, in tobacco by 379 % and in potato by 159 % (MAS). Potato grown in soil from tubers of transgenic plants demonstrated a moderate increase (44 %) of CK contents (MOD). Transgenic tobacco grown from seeds in vitro did not show any significant change in CK contents (NOT). Initial (RuBPC i and RuBPO i ) and total (RuBPC t ) activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO), and the activity of phosphoenolpyruvate carboxylase (PEPC) were not significantly affected by the transformation in the NOT plants. In the MOD plants, the RuBPCO activities were stimulated by up to 34 % whereas the PEPC activity was decreased by 17 %. On the other hand, all the measured enzyme activities were 32 -91 % lower in the MAS. Leaf area, fresh and dry masses, and chlorophyll and soluble protein contents also went down with increasing CK amounts in the transformants. Dependence of RuBPC i /RuBPO i and RuBPC t /PEPC ratios on the relative CK amounts in transgenic plants revealed that the individual enzyme activities were not affected uniformly. Endogenous CK contents in the MAS thus apparently exceeded an optimum needed for positive effects on many physiological traits and became a stress factor for such plants. plants with massive rise in CK contents; MOD -transgenic plants with moderate rise in CK contents; NOT -transgenic plants without rise in CK contents; PEPC -phosphoenolpyruvate carboxylase; RuBPC i,t , RuBPO i -carboxylating, resp. oxygenating operation of ribulose-1,5-bisphosphate carboxylase/oxygenase, subscripts: i -initial, t -total; RuBPCO -ribulose-1,5-bisphosphate carboxylase/oxygenase; SD -standard deviation; SE -standard error of the mean; Z -zeatin; ZR -zeatin riboside. Acknowledgements: I am grateful to Drs. P. Kostřica and M. Ondřej for providing experimental material (tubers, seeds, or in vitro regenerants), Drs. Ivana Macháčková and M. Strnad for performing cytokinin analyses, and Ing. Marie Zajícová for assisting with RuBPO activity assays. I also appreciate Ing. Marie Šimková for drawing the figures.

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Cytokinins in photoperiodic induction of flowering in Chenopodium species

Cited by 7 publications

References 0 publications

The fission yeast mitotic activator cdc25 and sucrose induce early flowering synergistically in the day‐neutral Nicotiana tabacum cv. Samsun

The fission yeast mitotic activator cdc25 and sucrose induce early flowering synergistically in the day‐neutral Nicotiana tabacum cv. Samsun

Growth and development of Mesembryanthemum crystallinum (Aizoaceae)

Extent of ipt gene expression and resulting amount of cytokinins affect activities of carboxylation enzymes in transgenic plants

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