scholarly journals Ultrastructural analysis of initial stages of dedifferentiation of root explants of Gentiana cruciata seedlings

2014 ◽  
Vol 71 (4) ◽  
pp. 287-297 ◽  
Author(s):  
Anna Mikuła ◽  
Teresa Tykarska ◽  
Jan Rybczyński ◽  
Mieczysław Kuraś
Keyword(s):  
Callus Formation ◽  
Induction Medium ◽  
Elongation Zone ◽  
Root Explants ◽  
Regular Type ◽  
Cell Divisions ◽  
Zone Cell ◽  
Dividing Cells ◽  
Gentiana Cruciata ◽  
Axial Cylinder

The studies were carried out on isolated roots of 10-day old seedlings of <em>Gentiana cruciata</em>, which were placed and cultured on induction medium of Murashige and Skoog (1962) supplemented with 1.0 mg/dm<sup>3</sup> dicamba + 0.l mg/dm<sup>3</sup> NAA + 2.00 mg/dm<sup>3</sup> BAP + 80.0 mg/dm<sup>3</sup> adenine sulphate. Changes in explants from the 3rd to the l lth day of culture with the help of light and electron microscope were observed. Observations showed gradual dedifferentiation of root tissues, which was seen earliest in cortex at the proximal end of the explant and shifted gradually inwards the root and towards distal parts of its elongation zone. The most intensive callus formation appeared at cut surface of explant, where proliferation of cells in both cortex and axial cylinder was recognised. In the distal part of the elongation zone, cell divisions occurred only in endoderm and in axial cylinder. The meristematic part of the root was inactive. Finally, the following areas were distinguished in the explant: (I) an area of intensive cell divisions, i.e., the elongation zone; (II) an area of cell dispersion; and (III) the inactive meristem. The ultrastructure brought evidences of cell reorganisation as the meaning of cell readiness to the division. Observations showed an increased activity of mitochondria and Golgi structures, thickening of walls and disappearance of plasmodesmal connections. Amyloplasts and lipid bodies in tissues in which they had been scarce or had not appeared before founding. Intensively dividing cells showed features of meristematic cells. They had dense cytoplasm with numerous organelles, large centrally located nuclei, and "nucleolar vacuoles" inside nucleoli. Cortex-derived callus formed aggregates. Both pericycle and endoderm produced callus of characteristic dense structure and regular type of divisions.

Utilization of Different Seedling Explants for in Vitro Propagation of Hibiscus syriacus

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 478e-479
Author(s):  
M.M. Jenderek ◽  
A.J. Olney
Keyword(s):  
Callus Formation ◽  
Adventitious Bud ◽  
Root Explants ◽  
Petiole Explants ◽  
Bud Formation ◽  
Hypocotyl Explants ◽  
Leaf Petiole ◽  
Adventitious Bud Formation ◽  
Hibiscus Syriacus

Hibiscus syriacus is a difficult species in micropropagation due to its endogenous contamination and recalcitrant shoot formation; therefore, studies on using explants other than shoot tip or axillary buds of growing shrubs were initiated. Three different seedling fragments (root, hypocotyl, and leaf petiole) from aseptically germinated seedlings of hibiscus (var. Aphrodite) were evaluated for adventitious bud formation, shoot and leaf development. The explants were cultured on McCown's woody plant basal salt medium supplemented with KNO3 (800 mg/L), adenine sulfate (80 mg/L) and MS vitamins containing BA or 2iP or TDZ at 0.5, 1.0, 2.2, 4.4 and 10 mM. Adventitious buds were present on all of the three different explants grown on medium containing TDZ; however, the most abundant bud formation, with many small leaves originating from callus was observed on hypocotyl explants cultured on medium with 1 mM of TDZ. Petiole explants were the most frequent to develop short shoots (≈15 mm) and one to nine leaves without callus formation, where 70% of hypocotyl and the root explants formed leaves originating from callus. Callus was induced on all explant types regardless of the level or type of cytokinin used. However, the number of shoots produced by any explant type was low, petioles cultured on 0.5 and 1mM of TDZ were the most suitable material for non-callus shoot development in H. syriacus. Hypocotyl explants proved to be an excellent source for adventitious bud formation but their ability to develop shoots needs to be investigated.

discordia mutations specifically misorient asymmetric cell divisions during development of the maize leaf epidermis

Development ◽  
1999 ◽  
Vol 126 (20) ◽  
pp. 4623-4633 ◽  
Author(s):  
K. Gallagher ◽  
L.G. Smith
Keyword(s):  
Cell Division ◽  
Preprophase Band ◽  
Cytochalasin D ◽  
Leaf Epidermis ◽  
Asymmetric Cell Divisions ◽  
Maize Leaf ◽  
Cell Divisions ◽  
Cytoskeletal Structure ◽  
Dividing Cells ◽  
Preprophase Bands

In plant cells, cytokinesis depends on a cytoskeletal structure called a phragmoplast, which directs the formation of a new cell wall between daughter nuclei after mitosis. The orientation of cell division depends on guidance of the phragmoplast during cytokinesis to a cortical site marked throughout prophase by another cytoskeletal structure called a preprophase band. Asymmetrically dividing cells become polarized and form asymmetric preprophase bands prior to mitosis; phragmoplasts are subsequently guided to these asymmetric cortical sites to form daughter cells of different shapes and/or sizes. Here we describe two new recessive mutations, discordia1 (dcd1) and discordia2 (dcd2), which disrupt the spatial regulation of cytokinesis during asymmetric cell divisions. Both mutations disrupt four classes of asymmetric cell divisions during the development of the maize leaf epidermis, without affecting the symmetric divisions through which most epidermal cells arise. The effects of dcd mutations on asymmetric cell division can be mimicked by cytochalasin D treatment, and divisions affected by dcd1 are hypersensitive to the effects of cytochalasin D. Analysis of actin and microtubule organization in these mutants showed no effect of either mutation on cell polarity, or on formation and localization of preprophase bands and spindles. In mutant cells, phragmoplasts in asymmetrically dividing cells are structurally normal and are initiated in the correct location, but often fail to move to the position formerly occupied by the preprophase band. We propose that dcd mutations disrupt an actin-dependent process necessary for the guidance of phragmoplasts during cytokinesis in asymmetrically dividing cells.

scholarly journals Rape embryogenesis. IV. Appearance and disappearance of starch during embryo development

2014 ◽  
Vol 51 (3-4) ◽  
pp. 381-387 ◽  
Author(s):  
Teresa Tykarska
Keyword(s):  
Apical Part ◽  
Embryo Axis ◽  
Starch Grains ◽  
Cell Divisions ◽  
Embryo Cells ◽  
Dividing Cells ◽  
Gradual Accumulation ◽  
Black Seeds ◽  
Mother Cells ◽  
Storage Starch

Starch appears first in the suspensor of the proembryo with two-cell apical part. It is observed in the embryo proper from the octant stage. At first it is visible in all the embryo cells in the form of minute transient grains which disappear during cell divisions. But the columella mother cells and their derivatives have persistent large grains. When the embryo turns green in the heart stage a gradual accumulation of storage starch begins and lasts to the end of embryogenesis. Storage starch grains appear first in the auter cortex layers of the hypocotyl where the largest grains are to be found later, and afterwards in all the other tissues. Starch is usually absent in the frequently dividing cells, but even there it appears in the form of minute grains after the end of cell divisions. Disappearance of starch starts when the intensive green colour of the seed coat begins to fade. The first to disappear are the smallest granules in the regions where they were noted latest. In the embryo axis the starch grains remain deposited longest in dermatogen and cortex cells in the lower hypocotyl part. They are visible there, still when the seed turns brown. In black seeds starch may be only found in the columella the cells of which throughout embryogenesis contain amyloplasts filled with starch. These grains disappear completely at the time when the seeds become dry.

scholarly journals Efficient Protoplast Regeneration Protocol and CRISPR/Cas9-Mediated Editing of Glucosinolate Transporter (GTR) Genes in Rapeseed (Brassica napus L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Xueyuan Li ◽  
Sjur Sandgrind ◽  
Oliver Moss ◽  
Rui Guan ◽  
Emelie Ivarson ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Shoot Regeneration ◽  
Gene Editing ◽  
Protoplast Culture ◽  
Callus Formation ◽  
Protoplast Regeneration ◽  
Induction Medium ◽  
Shoot Induction ◽  
Brassica Napus L ◽  
High Concentrations

Difficulty in protoplast regeneration is a major obstacle to apply the CRISPR/Cas9 gene editing technique effectively in research and breeding of rapeseed (Brassica napus L.). The present study describes for the first time a rapid and efficient protocol for the isolation, regeneration and transfection of protoplasts of rapeseed cv. Kumily, and its application in gene editing. Protoplasts isolated from leaves of 3–4 weeks old were cultured in MI and MII liquid media for cell wall formation and cell division, followed by subculture on shoot induction medium and shoot regeneration medium for shoot production. Different basal media, types and combinations of plant growth regulators, and protoplast culture duration on each type of media were investigated in relation to protoplast regeneration. The results showed that relatively high concentrations of NAA (0.5 mg l−1) and 2,4-D (0.5 mg l−1) in the MI medium were essential for protoplasts to form cell walls and maintain cell divisions, and thereafter auxin should be reduced for callus formation and shoot induction. For shoot regeneration, relatively high concentrations of cytokinin were required, and among all the combinations tested, 2.2 mg l−1 TDZ in combination with auxin 0.5 mg l−1 NAA gave the best result with up to 45% shoot regeneration. Our results also showed the duration of protoplast culture on different media was critical, as longer culture durations would significantly reduce the shoot regeneration frequency. In addition, we have optimized the transfection protocol for rapeseed. Using this optimized protocol, we have successfully edited the BnGTR genes controlling glucosinolate transport in rapeseed with a high mutation frequency.

scholarly journals Emerging mechanisms of asymmetric stem cell division

2018 ◽  
Vol 217 (11) ◽  
pp. 3785-3795 ◽  
Author(s):  
Zsolt G. Venkei ◽  
Yukiko M. Yamashita
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Division ◽  
Asymmetric Cell Division ◽  
Binary Outcomes ◽  
Cellular Mechanisms ◽  
Asymmetric Cell Divisions ◽  
Cell Divisions ◽  
Dividing Cells ◽  
Stem Cell Division

The asymmetric cell division of stem cells, which produces one stem cell and one differentiating cell, has emerged as a mechanism to balance stem cell self-renewal and differentiation. Elaborate cellular mechanisms that orchestrate the processes required for asymmetric cell divisions are often shared between stem cells and other asymmetrically dividing cells. During asymmetric cell division, cells must establish asymmetry/polarity, which is guided by varying degrees of intrinsic versus extrinsic cues, and use intracellular machineries to divide in a desired orientation in the context of the asymmetry/polarity. Recent studies have expanded our knowledge on the mechanisms of asymmetric cell divisions, revealing the previously unappreciated complexity in setting up the cellular and/or environmental asymmetry, ensuring binary outcomes of the fate determination. In this review, we summarize recent progress in understanding the mechanisms and regulations of asymmetric stem cell division.

scholarly journals 882 PB 276 IN VITRO PROPAGATION AND CHIMERAL TRAITS OF Cryptanthus `Marian Oppenheimer' (WIDE LEAF CLONE)

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 560c-560
Author(s):  
Yong Cheong Koh ◽  
Fred T. Davies
Keyword(s):  
In Vitro Propagation ◽  
Callus Formation ◽  
Adventitious Shoot ◽  
Shoot Formation ◽  
Induction Medium ◽  
Ms Medium ◽  
Periclinal Chimera ◽  
Adventitious Shoot Formation ◽  
L1 And L2

The leaves of vegetative stolons of greenhouse grown Cryptanthus `Marian Oppenheimer' (wide leaf clone) were cultured in modified MS media to induce adventitious shoot formation via callus formation. The best callus induction medium was basal MS medium with 10 μM NAA, IBA and BA. Pure green (843), maroon (3), striped (2) and albino plantlets were obtained. Most of the albino plantlets were stunted, tightly clumped together and impossible to score. The medium which produced the highest average number of non-albino plantlets was basal MS medium with 0.3 μM NAA, IBA and BA All non-albino plantlets were rooted in MS medium with 5.4 μM NAA and transplanted ex vitro with a survival rate of 96.7%. The maroon plantlets became green two weeks after transplanting. Histological studies revealed that C. `Marian Oppenheimer' (wide leaf clone) has two tunicas (L1 and L2) and a corpus (L3). Callus on the leaf explant arose mainly from the L2 and L3. Apparently C. `Marian Oppenheimer' (wide leaf clone) is a GWG periclinal chimera.

scholarly journals HISTOLOGICAL EXAMINATION OF IN VITRO ADVENTITIOUS BUD DEVELOPMENT ON HYPOCOTYLS OF FRASER FIR

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1102a-1102
Author(s):  
Carole H. Saravitz ◽  
Frank A. Blazich ◽  
Henry V. Amerson
Keyword(s):  
Growth Regulators ◽  
Induction Medium ◽  
Adventitious Bud ◽  
Naphthaleneacetic Acid ◽  
Abies Fraseri ◽  
Fraser Fir ◽  
Cell Clusters ◽  
Cell Divisions ◽  
Bud Induction

Hypocotyls of Fraser fir (Abies fraseri (Pursh) Poir.) were excised from seeds germination 9 days and placed on bud induction medium containing 10 mg/liter benzyladenine (BA) and 0.01 mg/liter naphthaleneacetic acid (NAA) or medium without growth regulators. After 3 days on medium containing growth regulators, cell divisions were localized in epidermal and subepidermal layers of the hypocotyl while similar cell divisions were not observed in control-treated hypocotyls. Cell clusters consisting of two to five cells were present after 7 days in hypocotyls placed on bud induction medium. In control-treated hypocotyls, stomata continued to develop and cells within the cortex became vacuolated during the first 2 weeks in culture. All hypocotyls were transferred to secondary medium after 3 weeks. Cell clusters continued to enlarge into meristemoids in hypocotyls initially placed on bud induction medium. Gradually, meristemoids developed into buds and cataphylls were observed covering bud meristems.

scholarly journals Plant Regeneration from Protocorm-derived Callus of Five Paphiopedilum Hybrids

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1101D-1101
Author(s):  
Michael Compton
Keyword(s):  
Plant Regeneration ◽  
Growth Regulator ◽  
Callus Induction ◽  
Callus Formation ◽  
Induction Medium ◽  
Regeneration Medium ◽  
Petri Dishes ◽  
Callus Induction Medium

Callus was induced from protocorms of five Paphiopedilum hybrids (Paph. 03-1, Paph. 03-4, Paph. 03-5, Paph. 03-6, and Paph. 03-7) on callus induction medium [MS inorganics (412.5 mg NH4NO3 instead of 1650 mg and 475 mg KNO3 instead of 1900 mg) and vitamins plus (per liter) 0.1 g myo-inositol, 30 g sucrose, and 2.5 g Gelrite; pH 5.5] containing various concentrations and combinations of thidiazuron (TDZ; 4.5 and 45 μm) and 2,4-D (4.5 and 45 μm). Callus formation was greatest for protocorms of Paph. 03-1, Paph. 03-4, Paph. 03-6, and Paph. 03-7. Among the most competent hybrids, callus formation was greatest among protocorms induced in medium containing 4.5 μm 2,4-D and 4.5 to 45 μm TDZ. Induced calli were transferred to 100 × 15 mm petri dishes containing 25 mL of PLB and plant regeneration medium (similar to callus induction medium) containing various concentrations of either benzyladenine (BA; 0.5, 5, or 10 μm), TDZ (0.25, 2.5, or 5 μm) or no growth regulator (control). PLB and plant formation was greatest on medium containing BA.

scholarly journals Studies on In Vitro Response to Callus Induction and Regeneration of Five High Yielding Indica rice Varieties

2019 ◽  
Vol 7 ◽  
pp. 97-104
Author(s):  
Md. Niuz Morshed Khan ◽  
Md. Monirul Islam ◽  
Dr. Md. Shahidul Islam
Keyword(s):  
Callus Induction ◽  
Callus Formation ◽  
Indica Rice ◽  
Induction Medium ◽  
Embryogenic Calli ◽  
Rice Varieties ◽  
New Variety ◽  
Increasing Demand ◽  
Embryogenic Callus Formation

Due to growing population, there is an increasing demand of rice production but the productivity of rice is lessened day by day. To overcome this problem various biotechnological tools can be used for developing various rice varieties. However, the lack of a simple and efficient protocol for callus induction, embryogenic callus formation and quick plant regeneration in this cereal crop. In this study embryogenic calli from mature seeds of five indica rice varieties viz. Binadhan-5, Binadhan-6, BRRI dhan-48, BRRI dhan-58 and IR-64 were observed that is done in four different types of media composition. The highest callus induction were observed in media containing Sucrose as a carbon source. Among those varieties Binadhan-6 and BRRI dhan-48 showed highest rate of callus induction respectively. This study will be useful for selecting suitable callus induction medium for callus induction in future that will be useful for not only national but also international plant breeders for producing new variety and so on.

scholarly journals In vitro morphogenic events in culture of Lotus corniculatus L. seedling root explants

2011 ◽  
Vol 75 (3) ◽  
pp. 191-200 ◽  
Author(s):  
Jan J. Rybczyński ◽  
Marta Karolkowska ◽  
Zygmunt Kaczmarek ◽  
Anna Mikuła ◽  
Agnieszka Fiuk
Keyword(s):  
Callus Formation ◽  
Shoot Proliferation ◽  
Lotus Corniculatus ◽  
Root Explants ◽  
Bud Formation ◽  
Seedling Root ◽  
Shoot Primordia ◽  
Explant Position ◽  
Callus Proliferation

The experiments were carried out on <em>Lotus corniculatus</em> (L.) seedling root explants of the cultivar varieties Skrzeszowicka, Caroll A10 and strain 175. Callus formation and shoot regeneration were the major explant response depended mainly on of the studied genotype and used plant growth regulators (PGRs). Primary cortex of proximal and distal end of explant was the most active tissue for callus proliferation. For shoot primordia differentiation deeper zones of cortex took a part. The process of meristematic centre initiation was not uniform and various level of shoot differentiation events were observed not earlier than 3 weeks of culture. Usually, the shoot primordia regeneration began on proximal rather than distal end of the explant. BAP rather than urea derivatives stimulated shoot proliferation in extended cultures. Increasing of BAP and TDZ concentrations brought about the explant polarity and expansion of the meristematic zones. The explant position in root did not have significant influence on the number of regenerated shoots. The cultures only had better bud formation by TDZ when compared to BAP. BAP stimulated bud formation and development of the shoots from them. Short term of TDZ treatment of explants stimulated meristem formation which developed into buds and shoots. CPPU stimulated callus proliferation and bud formation when explants pretreatment was prolonged from 12 to 36 hrs.

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