Ethylene formation in the leaves of short- and long-day tobacco during transition to flowering

1988 ◽  
Vol 30 (6) ◽  
pp. 422-426 ◽  
Author(s):  
Veronika N. Lozhnikova ◽  
V. I. Rakitin ◽  
J. Krekule ◽  
Ivana Macháčková ◽  
M. KChailakhyan
Keyword(s):  
Ethylene Formation ◽  
Long Day ◽  
Transition To Flowering

Changes in free IAA level in the leaves of short-and long-day tobacco during flowering and the effect of applied IAA on the transition to flowering

1990 ◽  
Vol 32 (5) ◽  
pp. 339-345 ◽  
Author(s):  
Veronika N. Lozhnikova ◽  
Ivana MacháĎková ◽  
J. Eder ◽  
Natalja Dudko ◽  
J. Krekule ◽  
...  
Keyword(s):  
Long Day ◽  
Transition To Flowering

scholarly journals GRUSP, an Universal Stress Protein, Is Involved in Gibberellin-dependent Induction of Flowering in Arabidopsis thaliana

2021 ◽  
Vol 499 (1) ◽  
pp. 233-237
Author(s):  
D. S. Gorshkova ◽  
I. A. Getman ◽  
L. I. Sergeeva ◽  
Vl. V. Kuznetsov ◽  
E. S. Pojidaeva
Keyword(s):  
Arabidopsis Thaliana ◽  
Stress Protein ◽  
Flowering Locus T ◽  
Gene Encoding ◽  
Universal Stress Protein ◽  
Long Day ◽  
Dna Insertion ◽  
Floral Repressor ◽  
Flowering Locus ◽  
Transition To Flowering

Abstract The effect of T-DNA insertion in the 3'-UTR region of Arabidopsis thaliana At3g58450 gene encoding the Germination-Related Universal Stress Protein (GRUSP) was studied. It was found that under a long-day condition this mutation delays transition to flowering of grusp-115 transgenic line that due to a reduced content of endogenous bioactive gibberellins GA1 and GA3 in comparison to the wild-type plants (Col-0). Exogenous GA accelerated flowering of both lines but did not change the time of difference in the onset of flowering between Col-0 and grusp-115. In addition to changes in GA metabolism, grusp-115 evidently has disturbances in realization of the signal that induces flowering. This is confirmed by the results of gene expression of the floral integrator FLOWERING LOCUS T (FT) and the floral repressor FLOWERING LOCUS C (FLC), which are key flowering regulators and acting opposite. We hypothesize that the formation of grusp-115 phenotype can also be affected by a low expression level of FT due to up-regulated FLC expression.

The early-flowering mutant efs is involved in the autonomous promotion pathway of Arabidopsis thaliana

Development ◽  
1999 ◽  
Vol 126 (21) ◽  
pp. 4763-4770 ◽  
Author(s):  
W.J. Soppe ◽  
L. Bentsink ◽  
M. Koornneef
Keyword(s):  
Arabidopsis Thaliana ◽  
Flowering Time ◽  
Double Mutant ◽  
Plant Size ◽  
Early Flowering ◽  
Wild Type ◽  
Late Flowering ◽  
Long Day ◽  
Short Days ◽  
Transition To Flowering

The transition to flowering is a crucial moment in a plant's life cycle of which the mechanism has only been partly revealed. In a screen for early flowering, after mutagenesis of the late-flowering fwa mutant of Arabidopsis thaliana, the early flowering in short days (efs) mutant was identified. Under long-day light conditions, the recessive monogenic efs mutant flowers at the same time as wild type but, under short-day conditions, the mutant flowers much earlier. In addition to its early-flowering phenotype, efs has several pleiotropic effects such as a reduction in plant size, fertility and apical dominance. Double mutant analysis with several late-flowering mutants from the autonomous promotion (fca and fve) and the photoperiod promotion (co, fwa and gi) pathways of flowering showed that efs reduces the flowering time of all these mutants. However, efs is completely epistatic to fca and fve but additive to co, fwa and gi, indicating that EFS is an inhibitor of flowering specifically involved in the autonomous promotion pathway. A vernalisation treatment does not further reduce the flowering time of the efs mutant, suggesting that vernalisation promotes flowering through EFS. By comparing the length of the juvenile and adult phases of vegetative growth for wild-type, efs and the double mutant plants, it is apparent that efs mainly reduces the length of the adult phase.

Descriptive and Quantitative Study of Ultrastructural Changes in the Apical Meristem of Mustard in Transition to Flowering

1974 ◽  
Vol 15 (3) ◽  
pp. 633-644
Author(s):  
A. HAVELANGE ◽  
G. BERNIER
Keyword(s):  
Apical Meristem ◽  
Sinapis Alba ◽  
Condensed Chromatin ◽  
Ultrastructural Changes ◽  
Point Counting ◽  
Meristematic Cells ◽  
Long Day ◽  
Genetic Activity ◽  
Loss Of Compactness ◽  
Transition To Flowering

Transition to flowering was induced in the shoot apical meristem of Sinapis alba (mustard), a long-day species, by subjecting vegetative plants to a single 22-h long day. The ultrastructural changes occurring in the meristematic cells during the complete morphogenetic switch were quantitatively investigated using both the planimetric and the point-counting stereological methods. The 2 methods yield very similar results and are thus equally appropriate for the study. The cell, nucleus, and dispersed chromatin sizes are greater in meristems of plants induced to flower (evoked meristems) than in meristems of control vegetative plants. A first size maximum is reached at 26 h after the start of the inductive long day and a second at 54 h. These 2 maxima occur just prior to 2 mitotic waves culminating respectively at 26-30 and 62 h. Neither the condensed chromatin size nor the number of chromocentre profiles per nucleus section change. Consequently the dispersed chromatin: condensed chromatin ratio increases in evoked meristems. This change is discussed in relation to current views on the differential genetic activity of the 2 kinds of chromatin. There is a late but large increase in size of the nucleolus. Dramatic changes in texture are associated with the enlargement of this organelle. These changes are the disappearance of the segregation of fibrillar and granular components and a loss of compactness due to marked vacuolation. All these changes in size and structure are interpreted as indicating a late increase in nucleolar synthesis of ribosomes in the evoked meristems.

scholarly journals Anatomical Changes in Rudbeckia hirta L. during Transition to Flowering

1993 ◽  
Vol 118 (6) ◽  
pp. 835-839 ◽  
Author(s):  
Richard L. Harkess ◽  
Robert E. Lyons
Keyword(s):  
Leaf Primordium ◽  
Floral Initiation ◽  
Anatomical Changes ◽  
Rudbeckia Hirta ◽  
Floral Stimulus ◽  
Long Day ◽  
Dividing Cells ◽  
Histochemical Examination ◽  
Short Days ◽  
Transition To Flowering

Histological and histochemical examination of floral initiation was conducted to determine the pattern of flowering in Rudbeckia hirta, a long-day (LD) plant. Plants were grown under 8-hour short days (SDs) until they had 14 to 16 expanded leaves. Half of the group of plants was moved to LD conditions consisting of natural daylength plus a 4-hour night interruption. Rudbeckia hirta had a pattern of differentiation in flowering similar to that reported in species requiring one inductive day for initiation. Rudbeckia hirta required 8 LDs for evocation and 18 LDs for completion of initiation. Involucral bracts initiated after 18 LDs, after which the receptacle enlarged and was capped by a meristematic mantle of cells signaling the start of development. Floret primordia did not initiate, even after 20 LDs. Increases in pyronin staining were observed in actively dividing cells of the procambium, leaf primordium, and corpus of the vegetative meristems. After 8 LDs, the pith rib meristem stained darkly, a result indicating the arrival of the floral stimulus. An increase in pyronin staining was also observed in the meristematic mantle covering the receptacle after 18 LDs, a result indicating increased RNA levels.

Descriptive and Quantitative Study of Ultrastructural Changes in the Apical Meristem of Mustard in Transition to Flowering

1974 ◽  
Vol 16 (2) ◽  
pp. 421-432
Author(s):  
A. HAVELANGE ◽  
G. BERNIER ◽  
A. JACQMARD
Keyword(s):  
Apical Meristem ◽  
Quantitative Methods ◽  
Succinic Dehydrogenase ◽  
Ultrastructural Changes ◽  
Cytoplasmic Matrix ◽  
Membrane Area ◽  
Early Effect ◽  
Long Day ◽  
Transition To Flowering ◽  
In Cells

Transition to flowering was induced in the shoot apical meristem of Sinapis alba (mustard), a long-day species, by subjecting vegetative plants to a single 22-h long day. The ultrastructural changes occurring in the meristematic cells during the complete morphogenetic switch were investigated by quantitative methods. The earliest detectable changes are seen 18 h after the start of the inductive long day. One of these changes is the replacement of the large vacuoles of the cells of vegetative meristems by an increased number of smaller vacuoles in the cells of meristems of plants induced to flower (evoked meristems). The other earliest change is an increase in size of the chondriome. Remarkably enough both changes have in common that they lead to an increase in membrane area and are thus concerned with increased membrane synthesis. In this respect this very early effect of the leaf-generated floral stimulus is very similar to that produced by various animal and plant hormones in their respective target tissues. The large rise in chondriome size is paralleled by an increase in succinic dehydrogenase activity. Both changes certainly reflect a rise in cellular respiratory activity which produces the necessary energy supply for the morphogenetic switch. As the size of the plastidome does not change during the transition to flowering, the plastidome:chondriome ratio decreases markedly. The size of the cytoplasmic matrix is greater in cells of evoked meristems than in cells of vegetative meristems. A first size maximum is reached at 26 h after the start of the long day and a second at 54 h. These 2 maxima occur just prior to 2 mitotic waves culminating respectively at 26-30 and 62 h. The increases in amount of endoplasmic reticulum (ER) and dictyosome number that are found in evoked meristems collected just prior to or at the time of the second mitotic wave are also probably related to the mitotic activation of the tissue. As the size of the vacuolar apparatus considered as a whole does not change at all and the size of the cytoplasmic matrix increases, the vacuoles:cytoplasm ratio decreases in evoked meristems collected following 26 h after the start of the long day. Also, there is an unexpected decrease in the nucleus:cytoplasm ratio in the cells of evoked meristems after 46 h.

The effect of daylength on the transition to flowering in phytochrome-deficient, late-flowering and double mutants of Arabidopsis thaliana

1995 ◽  
Vol 95 (2) ◽  
pp. 260-266 ◽  
Author(s):  
Maarten Koornneef ◽  
Corrie Hanhart ◽  
Patty van Loenen-Martinet ◽  
Hetty Blankestijn de Vries
Keyword(s):  
Arabidopsis Thaliana ◽  
Late Flowering ◽  
Transition To Flowering

Effect of Irradiance Level and Paclobutrazol on Reducation of Leaf Damage in Begonia × cheimantha

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 446d-446
Author(s):  
Beyounghan Yoon ◽  
Harvey J. Lang
Keyword(s):  
Day Treatment ◽  
Leaf Damage ◽  
Growth Retardants ◽  
Damage Development ◽  
Long Day ◽  
Leaf Chlorosis ◽  
Shade Cloth ◽  
Growing Conditions ◽  
Reduced Light ◽  
Shade Plants

Begonia × cheimantha (Christmas or Lorraine begonia) is a popular holiday crop in Europe, with certain cultivars having outstanding postharvest characteristics. Its commercial production in the southern United States has been limited by the occurrence of mottled leaf chlorosis and necrosis, apparently due to environmental stress. In this study, B. × cheimantha `Emma' was grown in the fall in a glass greenhouse at College Station, Texas, under either 0%, 60%, or 87% polyethylene shade cloth. Leaf chlorosis and necrosis was very severe on plants grown in full sun (≈650 mol·m–2·s–1), with slight chlorosis on plants under 60% shade. Plants under full sun, however, were more compact, flowered earlier, and had shorter peduncles with more flowers than those grown under shade. Reducing the vegetative long-day treatment period from 7 to 4 weeks had no effect on leaf damage development. Plants treated with paclobutrazol were shorter and had less leaf damage than untreated plants. Leaves of treated plants had a relatively higher concentration of soluble protein, chlorophyll, and enhanced activities of ascorbate peroxidase (AsA), dehydroascorbate (DHA) reductase, and monodehydro-ascorbate (MDHA) reductase than untreated plants. For Texas growing conditions, these preliminary studies indicate that B. × cheimantha should be grown under reduced light intensities, with excessive height and leaf damage being controlled with growth retardants such as paclobutrazol.

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