An Ultrastructure Study of Tumor Cells of Haworthia Plants Induced by 2,4-D

Author(s):  
J. S. Sullender ◽  
S. K. Majumdar

Treatment of normal callus cells of Haworthia variegata with high concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) promoted the development of tumor-type growth. At low concentrations (1 and 2 mg/liter), 2,4-D had little adverse effects on the growth and morphogenesis of the callus, however, in some tubes abnormal-appearing roots were detected. Calli on the media containing 5, 10 and 20 mg/liter of 2,4-D developed pink-brown pigmentation, produced numerous minute nodules, induced tumor-type growth, showed little differentiation and produced abnormal roots and leaves. Ultrastructure studies of auxin-induced tumors in some plants have been made by several investigators, however, no information is available on the fine structure of the 2,4-D induced tumor cells of Haworthia plants. Tissues from tumor and control groups were fixed in 2% osmium tetroxide, post-fixed in 4% glutaraldehyde, and embedded in Epon 812. Sections were cut on a Porter-Blum MT-2 ultramicrotome, stained with uranyl acetate-lead citrate and examined on a Philips Model 201 transmission electron microscope operating at 60 kV.

1972 ◽  
Vol 50 (12) ◽  
pp. 2471-2477 ◽  
Author(s):  
T. T. Lee

Peroxidase in tobacco callus tissue (Nicotiana tabacum, cv. White Gold) was resolved into three groups of isoenzymes by polyacrylamide gel electrophoresis, and a combined action of cytokinin, auxin, and gibberellin in their formation was clearly demonstrated. The most significant change was in a group of fast-migrating isoperoxidases, the development of which required both kinetin and indoleacetic acid. Kinetin was most stimulatory at 0.2 μM but became inhibitory with increasing concentrations. Indole acetic acid was effective at concentrations from 0.1 to 100 μM with an optimum at 10 μM. With both kinetin and indoleacetic acid at optimal concentrations, addition of gibberellic acid further increased the contents of the fast migrating isoperoxidases, but it was inactive in the absence of indoleacetic acid or in the presence of kinetin in 5 μM or higher concentrations. Cycloheximide, actinomycin D, and abscisic acid inhibited the formation of the fast-migrating peroxidases. Formation of the fast-migrating isoperoxidase in the tissue was associated with tumor-type growth.2,4-Dichlorophenoxyacetic acid had a dual effect on peroxidase; at low concentrations (0.1 to 1 μM) it promoted a fast-migrating isoperoxidase; at high concentrations (10 to 100 μM) it inhibited the fast-migrating isoperoxidase but caused a significant increase in other isoperoxidases of lower electrophoretic mobilities.


1984 ◽  
Vol 62 (6) ◽  
pp. 1245-1249 ◽  
Author(s):  
L. S. Kott ◽  
K. J. Kasha

Somatic embryogenesis was induced in callus previously initiated from immature embryos of barley. These cultures ranged in age from 6 weeks to 30 months. Embryoids were readily initiated from homogenized suspension-grown aggregates when plated on modified B5 media with 2,4-dichlorophenoxyacetic acid. Low concentrations (0.1 and 0.05 mg∙L−1) of abscisic acid promoted further maturation of embryoids, while gibberellic acid (1 mg∙L−1) and kinetin (0.1 mg∙L−1) were used in the media to encourage embryoid germination. The development of somatic embryoids from initiation through maturation and germination is described.


2011 ◽  
Vol 47 (No. 3) ◽  
pp. 114-122 ◽  
Author(s):  
S.H. Ardebili ◽  
M.E. Shariatpanahi ◽  
R. Amiri ◽  
M. Emamifar ◽  
M. Oroojloo ◽  
...  

The effect of 2,4-dichlorophenoxyacetic acid (2,4-D) applied at high concentrations for a short time was investigated as a novel stress for induction of microspore embryogenesis for the first time. Brassica napus L. cvs. Topas and Hyola 420 were used as model plants for testing this hypothesis. Microspores were subjected to 2,4-D at 4 concentrations (15, 25, 35 and 45 mg/l) for 15–45 min while the classical heat shock was used as the control treatment. Among 2,4-D treatments in Topas, the highest yield of torpedo-stage embryos was achieved at 15 mg/l 2,4-D for 30 min while more normal plantlets were produced when 2,4-D (25 mg/l for 30 min) was applied to the microspores. In Hyola 420 the results showed a lower number of embryos and normal plantlets at all concentrations of 2,4-D. Although Hyola 420 was almost equally embryogenic as Topas after heat shock treatment, large differences between genotypes (concerning embryogenic response) occurred after 2,4-D treatment. However, the mean number of embryos and regenerants was higher in heat shock as compared to 2,4-D induced stress (one magnitude of order). According to the results obtained, 2,4-D can be introduced as a new stress for induction of embryogenesis in microspores similarly like in zygotic and somatic cells. This novel stress is very important for plant species whose microspores are extremely sensitive to classical stresses.


Weed Science ◽  
1968 ◽  
Vol 16 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Israel Feldman ◽  
M. K. McCarty ◽  
C. J. Scifres

Herbicides applied April 30, May 10, or October 14 gave best control of musk thistle (Carduus nutansL.). The most effective herbicide at all dates and rates was 4-amino-3,5,6-trichloropicolinic acid (picloram). Two lb/A of 2-methoxy-3,6-dichlorobenzoic acid (dicamba) also was effective at all spring dates. Two lb/A of 2,4-dichlorophenoxyacetic acid (2,4-D) resulted in excellent control of musk thistle when applied May 10 or October 14.More musk thistle seedlings became established in nongrazed, cool season grass pastures than in nongrazed, mixed warm season grass pastures. Greater germination was attributed to the reserve moisture and accumulation of litter which served as an excellent germination medium. However, only one musk thistle plant remained in the nongrazed pastures 1 year after seeding. The remainder of the seedlings and young rosettes found in the protected areas in 1965 had succumbed to the heavy competition by 1966.


2002 ◽  
Vol 29 (5) ◽  
pp. 575 ◽  
Author(s):  
Nello Ceccarelli ◽  
Alessandra Mondin ◽  
Roberto Lorenzi ◽  
Piero Picciarelli ◽  
Fiorella Lo Schiavo

In the present work, the characterization of two variant cell lines of carrot capable of growing in high (92 μmol L–1) concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) is reported. Both these cell lines (4w77 and 4w13) show a significantly lower uptake of 2,4-D with respect to wild-type (wt) cells. In contrast to wt cells, influx of IAA is not reduced by the addition of 100 μM 2,4-D and the presence of this compound appears to stimulate IAA uptake. When grown in the presence of high concentrations of 2,4-D, both 4w77 and 4w13 cells show behavioural differences: instead of lowering the endogenous level of free IAA, the two resistant lines react to the high exogenous concentrations of auxin by raising the level of the free hormone. In 4w77 cells, this is accomplished by reduction of auxin released in the external medium or converted to amide-linked conjugates. In 4w13 cells, the final level of endogenous IAA is an equilibrium between increased synthesis of IAA and a massive release into the medium of the ester- and free-forms of IAA. Both cell lines show disturbances in embryogenesis: line 4w77 forms globular embryos that only mature into aberrant forms having multiple axes, whereas line 4w13 has completely lost its morphogenic capacity.


2016 ◽  
Vol 19 (2) ◽  
pp. 168
Author(s):  
Toni Herawan ◽  
Mohammad Na'iem ◽  
Sapto Indrioko ◽  
Ari Indrianto

Sandalwood (Santalum album L.) is native species of Indonesia, especially in East Nusa Tenggara, is oneof the twenty two species of the genus Santalum in the world. Sandalwood is an important tree because it hashigh economic value can produce sandal oil these can be used for perfumes, cosmetics, pharmaceuticals, andare often used in religious ceremonies. In vitro particularly somatic embryogenesis has been widely appliedin the propagation of sandalwood. The Objective of this research is to obtain regeneration of sandalwoodthrough somatic embryogenesis using leaves explant from various clones. Medium for embryo induction is MS(Murashige and Skoog, 1962) solid medium containing treatment of 2,4-D (2,4-Dichlorophenoxyacetic acid)at various concentrations. To the media 0,15 mg /l kinetin, 40 g/l sucrose, and 2,5 g/l gelrite were added.Culture were incubated in the dark. Medium for Embryo development (maturation) is MS solid mediumcontaining treatment of BAP (Benzyl-amino-purine) at various concentrations. To the media 0,01 mg /l NAA(Napthalene-acetic-acid), 40 g/l sucrose, and 2,5 g/l gelrite were added. Culture were incubated in the light. Tostudy the specifi c structure of sandalwood somatic embryo early detection was conducted using histologicalanalysis. Results of anova showed that the clones, media, and interaction between clones with media did notsignifi cantly affect the development of sandalwood callus percentage. Results of anova showed that the clonesand BAP concentration signifi cantly effect to the embryo development of sandalwood.


2014 ◽  
Vol 36 (3) ◽  
pp. 664-672 ◽  
Author(s):  
Mauro Brasil Dias Tofanelli ◽  
Pytágoras Leal Freitas ◽  
Giuliano Elias Pereira

Viticulture is an important agricultural activity in semiarid northeastern Brazil, and the quality and ease of vine propagation are very important in this context. This study evaluated the use of 2,4-dichlorophenoxyacetic acid (2,4-D) as an alternative to indolebutyric acid (IBA) in the rooting of vine rootstock cuttings. The trial was conducted at the Universidade Federal de Sergipe (São Cristóvão-SE) between January and March 2010 with cuttings of the rootstocks of 'IAC-766', 'IAC-572', and 'Paulsen 1103' treated with 2,4-D or IBA applied at concentrations of 0, 1000, 2000, or 3000 rng-L-1 for 5 s and planted in a field on washed sand. At 56 days after planting, the percentages of rooted, sprouted, callused, and dead cuttings were evaluated, and also the average number and length of the rooted cuttings. The results showed that 2,4-D was not superior to IBA in the characteristics wanted for the rooting process of the vine rootstock cuttings. The vine rootstocks showed potential for propagation by cutting without auxin application. It was observed that the high concentrations were the worst for the rooting of the cuttings.


2014 ◽  
Vol 14 (2) ◽  
pp. 108-115 ◽  
Author(s):  
Sandra Zorat Cordeiro ◽  
Naomi Kato Simas ◽  
Anaize Borges Henriques ◽  
Alice Sato

Mandevilla guanabarica is an endemic plant from Brazil, with pharmacological and ornamental potential, both unexplored. This study established the best culture medium for in vitro plant maintenance, efficient protocol for its regeneration, and callogenesis from different explants excised from in vitro-grown plants. Woody plant medium with double boron concentration (WPM B) plus 2.27 µM thidiazuron or 0.49 µM 2-isopentenyladenine provided multiplication rates higher than 1:6. Shoots were 100% rooted on WPM B. After acclimatization, plants showed 83% survival. For callogenesis, the use of MS media supplemented with high concentrations of picloram or 2,4-dichlorophenoxyacetic acid produced, respectively, friable or compact non-morphogenic calluses from different types of explants. This micropropagation protocol allows the production of seedlings of M. guanabarica for ornamental or commercial uses, and for conservation purposes; calluses can be used to establish suspension cultures in prospecting for bioactive compounds.


1983 ◽  
Vol 61 (4) ◽  
pp. 1058-1063 ◽  
Author(s):  
Karol E. Paterson

High concentrations of four auxins, naphthalene acetic acid, indole 3-acetic acid, 2,4-dichlorophenoxyacetic acid, and indole 3-butyric acid, added to leaf segments of Crassula argentea in agar culture eliminate the strong polarity of the regeneration by inducing the formation of distal plantlets. The auxins also changed the normal wound response by inducing the formation of callus on the cut surfaces. All of the auxins increased the numbers of roots formed and inhibited the number of shoots. Unlike cytokinin, which had no effect on the polarity but altered the developmental sequence of regeneration, none of the auxins had any effect on the normal developmental sequence of regeneration, but did affect the morphology of the newly formed roots. There were differential concentration responses for each of the four auxins.


CORD ◽  
2016 ◽  
Vol 32 (2) ◽  
pp. 6
Author(s):  
Carlos Oropeza

This paper focuses on the research efforts carried out by CICY in Mexico on micropropagation of coconut. They started during the nineties in collaboration with Wye College (UK) and ORSTOM-CIRAD (France), with the development of a protocol that was reproducible and more efficient than previous ones, based on plumule explants grown in different media based on Y3 medium added with activated charcoal, gelling agent and of particular importance growth regulators 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). Within the next decade basic research was carried out to study the process of somatic embryogenesis from plumule explants, with an approach including morpho-histological, physiological, biochemical and molecular points of view, in order to gain knowledge that could be useful to further improvement of the process. Also different practical approaches were tested including changes in the media formulation, embryogenic callus multiplication and secondary somatic embryogenesis. As a result a highly efficient protocol was developed that could potentially yield over a hundred thousand somatic embryos from a single plumule explant. Embryos were able to germinate and convert to plantlets, that after planting, successfully grew to sexual maturity and fruit production. This protocol is currently being scaled up to a semi-commercial level. Also within the past five years, a protocol using rachilla explants has been developed for the production of embryogenic callus and its multiplication, and embryos produced were able to germinate and convert to plantlets, setting the basis to develop a process for massive  propagation of coconut, such as the one already developed using plumule explants.


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