Etude du bourgeonnement in vitro de l'écaille du bulbe de Tulipe

1979 ◽  
Vol 57 (19) ◽  
pp. 1986-1993 ◽  
Author(s):  
Simonne Rivière ◽  
Jean-François Muller
Keyword(s):  
Low Temperature ◽  
Vegetative Propagation ◽  
Culture Period ◽  
Bulb Formation ◽  
Bud Initiation

Vegetative propagation of tulips in vitro, not performed until now, is obtained using as explants scales of daughter bulbs collected in winter. Twenty-five percent of these explants give rise to neoformed buds within 6 months. These buds evolve into bulbs which are able to develop in the soil. Their ontogeny is studied histologically, from the beginning of the culture to the neoformed bulb formation. A treatment with low temperature and darkness at the beginning of the culture period promotes an earlier bud initiation.

scholarly journals Low temperature storage and in vitro germination of cherimoya (Annona cherimola Mill.) pollen

2006 ◽  
Vol 108 (1) ◽  
pp. 91-94 ◽  
Author(s):  
J. Lora ◽  
M.A. Pérez de Oteyza ◽  
P. Fuentetaja ◽  
J.I. Hormaza
Keyword(s):  
Low Temperature ◽  
In Vitro Germination ◽  
Low Temperature Storage ◽  
Annona Cherimola ◽  
Temperature Storage

scholarly journals Mechanisms of idiotype suppression. I. In vitro generation of idiotype-specific suppressor T cells by anti-idiotype antibodies and specific antigen.

1979 ◽  
Vol 149 (6) ◽  
pp. 1371-1378 ◽  
Author(s):  
B S Kim
Keyword(s):  
T Cells ◽  
Specific Antigen ◽  
Suppressor Cells ◽  
Culture Period ◽  
Spleen Cells ◽  
Suppressor T Cells ◽  
Myeloma Protein ◽  
Specific Suppressor T Cells

Normal BALB/c spleen cells are unresponsive in vitro to the phosphorylcholine (PC) determinant in the presence of anti-idiotype antibodies specific for the TEPC-15 myeloma protein (T15) which carries an idiotypic determinant indistinguishable from that of most anti-PC antibodies in BALB/c mice. The possibility that idiotype-specific suppressor cells may be generated during the culture period was examined by coculturing the cells with untreated syngeneic spleen cells. Cells that had been preincubated with anti-T15 idiotype (anti-T15id) antibodies and a PC-containing antigen, R36a for 3 d, were capable of specifically suppressing the anti-PC response of fresh normal spleen cells, indicating that idiotype-specific suppressor cells were generated during the culture period. The presence of specific antigen also appeared to be necessary because anti-T15id antibodies and a control antigen, DNP-Lys-Ficoll, were not capable of generating such suppressor cells. Suppressor cells were induced only in the population of spleen cells nonadherent to nylon wool and the suppressive activity was abrogated by treatment with anti-Thy 1.2 serum and complement. These results indicate that anti-idiotype antibodies and specific antigen can generate idiotype-specific suppressor T cells in vitro. These in vitro results may reflect in vivo mechanisms of idiotype suppression.

Floral induction in date palm seedlings (Phoenix dactylifera var. Deglet Nour) cultured in vitro

1987 ◽  
Vol 65 (1) ◽  
pp. 137-142 ◽  
Author(s):  
Saïda Ammar ◽  
Abdellatif Benbadis ◽  
Bal Krishna Tripathi
Keyword(s):  
Date Palm ◽  
Root Formation ◽  
Early Stage ◽  
Floral Induction ◽  
Phoenix Dactylifera ◽  
Flower Bud ◽  
Precocious Flowering ◽  
Cultural Conditions ◽  
Bud Initiation

Flower bud initiation in 5-month-old seedlings of date palm (Phoenix dactylifera L. var. Deglet Nour) was studied under controlled conditions. Normally inflorescence formation in mature plants takes 8 to 10 years. In juvenile plants inflorescence formation was induced in a 16-h day at 28 °C, by a combination of 6-benzylaminopurine, indoleacetic acid, and glucose or sucrose. The present investigation has determined favourable cultural conditions for floral induction in date palm in vitro at a very early stage of ontogeny. Both male and female flowers were induced on young plants. Floral induction usually occurred only when root formation was completely inhibited. The apparent antagonism between root formation and floral development suggests a possible competition in the young plant for growth substances, although production of floral inhibitory substances from the root cannot be precluded. These observations on the induction of precocious flowering in date palm seedlings suggest a model of development, corresponding to neoteny, of this tree as an herb.

scholarly journals Arabidopsis ADF5 Acts as a Downstream Target Gene of CBFs in Response to Low-Temperature Stress

2021 ◽  
Vol 9 ◽  
Author(s):  
Pan Zhang ◽  
Dong Qian ◽  
Changxin Luo ◽  
Yingzhi Niu ◽  
Tian Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Actin Cytoskeleton ◽  
Temperature Stress ◽  
Regulatory Element ◽  
Low Temperature Stress ◽  
Knockout Mutant ◽  
Triple Mutant ◽  
Freezing Resistance

Low temperature is a major adverse environment that affects normal plant growth. Previous reports showed that the actin cytoskeleton plays an important role in the plant response to low-temperature stress, but the regulatory mechanism of the actin cytoskeleton in this process is not clear. C-repeat binding factors (CBFs) are the key molecular switches for plants to adapt to cold stress. However, whether CBFs are involved in the regulation of the actin cytoskeleton has not been reported. We found that Arabidopsis actin depolymerizing factor 5 (ADF5), an ADF that evolved F-actin bundling function, was up-regulated at low temperatures. We also demonstrated that CBFs bound to the ADF5 promoter directly in vivo and in vitro. The cold-induced expression of ADF5 was significantly inhibited in the cbfs triple mutant. The freezing resistance of the adf5 knockout mutant was weaker than that of wild type (WT) with or without cold acclimation. After low-temperature treatment, the actin cytoskeleton of WT was relatively stable, but the actin cytoskeletons of adf5, cbfs, and adf5 cbfs were disturbed to varying degrees. Compared to WT, the endocytosis rate of the amphiphilic styryl dye FM4-64 in adf5, cbfs, and adf5 cbfs at low temperature was significantly reduced. In conclusion, CBFs directly combine with the CRT/DRE DNA regulatory element of the ADF5 promoter after low-temperature stress to transcriptionally activate the expression of ADF5; ADF5 further regulates the actin cytoskeleton dynamics to participate in the regulation of plant adaptation to a low-temperature environment.

scholarly journals Trichomes Morphology and Essential Oils Characterization of Field-Growing and In Vitro Propagated Plants of Lavandula pedunculata

2008 ◽  
Vol 14 (S3) ◽  
pp. 148-149 ◽  
Author(s):  
M. Zuzarte ◽  
A.M. Dinis ◽  
C. Cavaleiro ◽  
J. Canhoto ◽  
L. Salgueiro
Keyword(s):  
Chemical Composition ◽  
Antifungal Activity ◽  
Essential Oils ◽  
Vegetative Propagation ◽  
Leaf Trichomes ◽  
Economic Exploitation ◽  
Selection Of

The selection of native Lavandula species and their economic exploitation have increased in the last few years. Micropropagation techniques have been used as an alternative for vegetative propagation allowing the multiplication of selected genotypes and chemotypes. Our previous studies showed that the essential oils of Lavandula pedunculata have an important antifungal activity against dermatophyte strains. Therefore, a new line of investigation concerning the in vitro culture of this species is justified. In the present study we compare the morphology of the leaf trichomes and the chemical composition of their essential oils in both field-growing and in vitro propagated plants.

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