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1.
P. I. P. Perera V. Hocher J.-L. Verdeil H. D. D. Bandupriya D. M. D. Yakandawala L. K. Weerakoon 《Plant Cell, Tissue and Organ Culture》2008,92(3):293-302
Conditions for induction of androgenesis in coconut cv. Sri Lanka Tall were studied. Anthers collected from inflorescences
at four maturity stages were given heat (38°C) or cold (4°C) pretreatments for 1, 3, 6 and 14 days, either prior to or post
inoculation. Three different basal media and different anther densities were also tested. Androgenesis was observed only in
anthers collected from inflorescences 3 weeks before splitting (WBS) and after a heat pretreatment at 38°C for 6 days. Modified
Eeuwens Y3 liquid medium supplemented with 100 μM 2,4-dichlorophenoxyacetic acid (2,4-d), 0.1% activated charcoal and 9% sucrose was effective in inducing an androgenic response. The lowest anther density tested,
10 per petri plate, was found to be the optimal density. When androgenic calli or embryos were subcultured to Y3 medium containing 66 μM 2,4-d, followed by transfer to Y3 medium without plant growth regulators and finally to Y3 medium containing 5 μM 6-benzyladenine (BA) and 0.35 μM gibberellic acid (GA3), plantlets regenerated at a frequency of 7%. Histological study indicated that the calli and embryos originated from the
inner tissues of the anthers. Ploidy analysis of calli and embryos showed that they were haploid. This is the first report
of successful androgenesis yielding haploid plants from coconut anthers. 相似文献
2.
The present study reports the analyses of both isoprenoid and aromatic cytokinins in the coconut palm by combined high performance liquid chromatography and group specific enzyme immunoassays (HPLC-ELISA). The results showed that the isoprenoid cytokinins were several fold more abundant than the aromatic cytokinins in each of the plant parts analysed: immature inflorescence, shoot apical meristem (SAM), spear leaf and embryo. Within the isoprenoid cytokinins, the most abundant ones by type were the zeatin- (Z-), the isopentenyladenine- (iP-) and the dihydrozeatin- (DHZ-) type in decreasing order for most plant parts studied, and individually, zeatin riboside (ZR) or zeatin riboside-5-monophosphate (ZR5P) depending on the part. In the case of the iP-type cytokinins, the results showed that its 9-glucoside was the most abundant one in most parts. The isoprenoid cytokinin profiles in coconut showed a predominant pattern of 9-conjugation as a major metabolism route for these cytokinins. Analyses also showed the occurrence of the aromatic cytokinin 6-benzylaminopurine (BAP) and its riboside (BAPR), 9-glucoside (BAP9G), and nucleotide (BAPR5P). Their presence in coconut palm was unequivocally identified after permethylation by gas chromatography-mass spectrometry. They were more concentrated in the embryo and in the immature inflorescence than in the other two parts studied, however their concentration in each part was several times lower than that of isoprenoid cytokinins. All four were detected in each of the parts studied. The most abundant ones were BAPR and BAP9G in immature inflorescence; and BAPR in all of the other parts. When all cytokinins analysed are considered, differences between the plant parts studied were found. The zygotic embryos showed the highest content, double that in immature inflorescence, and five times more that in spear leaf and SAM. These differences are even greater when individual cytokinins are compared. 相似文献
3.
Morphological and histological changes during somatic embryo formation from coconut plumule explants
L. Sáenz A. Azpeitia B. Chuc-Armendariz J. L. Chan J. -L. Verdeil V. Hocher C. Oropeza 《In vitro cellular & developmental biology. Plant》2006,42(1):19-25
Summary Studies on the development of protocols for the clonal propagation, through somatic embryogenesis, of coconut have been reported
for the past three decades, mostly using inflorescence explants, but with low reproducibility and efficiency. Recent improvements
in these respects have been achieved using plumular explants. Here, we report a developmental study of embryogenesis in plumule
explants using histological techniques in order to extend our understanding of this process. Coconut plumule explants consisted
of the shoot meristem including leaf primordia. At day 15 of culture, the explants did not show any apparent growth; however,
a transverse section showed noticeable growth of the plumular leaves forming a ring around the inner leaves and the shoot
meristem, which did not show any apparent growth. At day 30, the shoot meristem started to grow and the plumular leaves continued
growing., At day 45, the explants were still compact and white in color, but showed partial dedifferentiation and meristematic
cell proliferation leading to the development of callus structures with a translucent appearance. After 60 d, these meristematic
cells evolved into nodular structures. At day 75, the nodular structures became pearly globular structures on the surface
of translucent structures, from which somatic embryos eventually formed and presented well-developed root and caulinar meristems.
These results allow better insights and an integrated view into the somatic embryogenesis process in coconut plumule explants,
which could be helpful for future studies that eventually could lead us to improved control of the process and greater efficiency
of somatic embryo and plantlet formation. 相似文献
4.
Perera PI Hocher V Verdeil JL Doulbeau S Yakandawala DM Weerakoon LK 《Plant cell reports》2007,26(1):21-28
Unfertilized ovaries isolated from immature female flowers of coconut (Cocos nucifera L.) were tested as a source of explants for callogenesis and somatic embryogenesis. The correct developmental stage of ovary explants and suitable in vitro culture conditions for consistent callus production were identified. The concentration of 2,4-dichlorophenoxyacetic acid (2,4-D) and activated charcoal was found to be critical for callogenesis. When cultured in a medium containing 100 μM 2,4-D and 0.1% activated charcoal, ovary explants gave rise to 41% callusing. Embryogenic calli were sub-cultured into somatic embryogenesis induction medium containing 5 μM abscisic acid, followed by plant regeneration medium (with 5 μM 6-benzylaminopurine). Many of the somatic embryos formed were complete with shoot and root poles and upon germination they gave rise to normal shoots. However, some abnormal developments were also observed. Flow cytometric analysis revealed that all the calli tested were diploid. Through histological studies, it was possible to study the sequence of the events that take place during somatic embryogenesis including orientation, polarization and elongation of the embryos. 相似文献
5.
When 7-d-old plantlets of spinach (Spinacia oleracea L.) were immersed with their roots for 24 h in 25 mg/l gibberellic acid (GA3), or 15 mg/l 6-benzylaminopurine (6-BAP), or 15 mg/l indole-3-acetic acid (IAA), or 10 mg/l abscisic acid (ABA) and subsequently grown on long (18-h) days, the ratio of plants with male and female flowers, which in the controls was almost 1:1 (48 and 52%, respectively), was greatly altered. The treatments with 6-BAP, IAA and ABA raised the percentage of female plants to 88, 76 and 71%, respectively; the GA3 treatment increased the percent of male plants to 79%. When young, vegetative spinach plants (3 visible leaves) grown in 18-h days were cut a the root neck, and the shoots grown with their bases in nutrient solution, with adventitious roots either being allowed to develop or being systematically removed, 85% of the plants without roots became males, 85% of those with roots became females. But if the cut shoots were first, for 28 h, placed in a 15-mg/l 6-BAP solution and then grown in the absence of roots, the percent of female plants was restored to 84. These results fully agree with those obtained previously with hemp, namely, that plant growth regulators exert a regulating effect on the sex expression of dioecious plants when applied through the roots in early stages of development; that the root system plays an important role in determining the sex of these plants, that this role of the roots is associated with the synthesis of cytokinins in them. Dioecious short- and long-day plants do not differ in these respects. 相似文献
6.
Begoña Echavarri Mercedes Soriano Luis Cistué M. Pilar Vallés Ana M. Castillo 《Plant Cell, Tissue and Organ Culture》2008,93(3):295-301
The effect of ZnSO4 concentration on barley (Hordeum vulgare L.) microspore embryogenesis was investigated using cultivars of different androgenetic response. Concentrations from 0 (control)
to 600 μM in the stress pre-treatment medium alone or in combination with 30 (control) to 600 μM in the embryo induction medium
were assayed in anther culture. Incorporation of Zn2+ in the pre-treatment medium itself did not affect microspore embryogenesis. The optimum concentration in the stress pre-treatment
and induction media was 180 μM for cultivars (cvs.) Igri and Reinette, and 90 μM for cv. Hop. A significant increase of 30
and 300% in cv. Igri and Reinette, respectively, were produced with 180 μM ZnSO4 in both the number of embryos and green plants. In order to confirm the effect of Zn2+ on microspore embryogenesis this micronutrient was incorporated in the induction medium of isolated microspore cultures of
cv. Igri. Concentrations of 90–300 μM ZnSO4 resulted in an increase of 40–53% in the number of embryos and green plants. All these results indicate that the beneficial
effect of Zn2+ is exerted mainly during the culture phase, increasing the number of embryos, leading to an increased number of green plants,
but it had no effect on percentage of regeneration or green plants. 相似文献
7.
A cell culture of anise was grown in the presence or absence of 2,4-dichlorophenoxyacetic acid (2,4-D). Application of isopentenyladenine or isopentenyladenosine (4·10-8 to 4·10-7 M) to the proembryonic culture (+2,4-D) yielded an increase of the cell density, in contrast to a proembryonic culture grown without exogenous application of cytokinins. Embryogenesis was induced by transferring the cells to a hormone-free medium. Embryo development was promoted by isopentenyladenine and isopentenyladenosine (5·10-8 to 5·10-7 M), higher concentrations (5·10-6 M) inhibited embryogenesis. The effect of cytokinins on embryogenesis was only promotive until the third day of culture, i.e. coincident with cell growth rather than differentiation.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- i6Ade
isopentenyladenine
- i6Ado
isopentenyladenosine 相似文献
8.
M. Jeganathan 《Plant and Soil》1990,124(2):265-271
The widespread deficiency of magnesium in coconut acts as a limiting factor to increased production. Two ongoing experiments on potassium-magnesium (K-Mg) interaction in coconut conducted in lateritic gravels (ultisols), in the wet and intermediate agroclimatic zones of Sri Lanka showed significant yield responses (P=0.01) to differential K treatments, in the wet zone, but not in the intermediate zone. Differential Mg treatments, however, did not give rise to yield responses. Leaf and nut water analysis showed significant changes in the concentrations of Na, K and Cl (P=0.001), with a distinct inverse relationship between Na and K when K was applied. Differential Mg applications showed a significant effect only for leaf Mg (P=0.001), in the fourth year of the experiment, in the wet zone. Results indicate the usefulness of nut water analysis as an additional diagnostic tool, for Na, K and Cl. 相似文献
9.
The influence of growth regulators absorbed by the root on sex expression in hemp plants 总被引:5,自引:1,他引:4
Application, through the root system, of growth regulators to hemp (Cannabis sativa L.) plants having 2–3 pairs of visible leaves caused pronounced shifts of sex expression in the adult individuals. Treatment with gibberellic acid (25 mg/l) resulted in more than 80% of the plants being male, i.e. having staminate flowers (controls, ca. 30%). Treatment with 6-benzylaminopurine and with indole-3-acetic acid (in either case, 15 mg/l) resulted in all plants being either female (pistillate flowers) or intersexes (bisexual flowers); treatment with abscisic acid (10 mg/l) had a similar but somewhat less pronounced effect. 相似文献
10.
A method was developed for the rearing of coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae), and its predatory mite Neoseiulus baraki (Athias-Henriot) (Acari: Phytoseiidae) on embryo culture seedlings of coconut (Cocos nucifera) in the laboratory. Seedlings in the ages of <2, 2–4 and 4–6 months were infested with 75 field-collected coconut mites and
the population growth was determined up to six weeks after introduction. The populations of coconut mites increased exponentially
up to five weeks after introduction and declined thereafter on seedlings of all ages with significant differences among the
three groups of seedlings occurring over time. At week 5, a significantly higher mean number (±SE) of coconut mites (20,098 ± 3,465)
was bred on 4–6-month-old seedlings than on smaller seedlings, and on the largest seedlings the numbers were highest at all
time intervals, except at week 2. Neoseiulus baraki was reared on embryo culture seedlings of the three age groups infested with coconut mites, by introduction of five female
deutonymphs and one male, three weeks after introducing coconut mites. Predator numbers progressed significantly over time,
but the size of seedlings did not significantly influence the numbers. On all groups of seedlings, the mean
number of N. baraki increased up to two weeks after introduction on to seedlings and then declined. Many coconut mites were successfully reared
in the laboratory for a longer period by this method and it could also be used as an alternative method to rear N. baraki. Development of this method may contribute to the progress of studies on the biology and ecology of coconut mite and its interactions
with natural enemies. 相似文献
11.
Summary Germination of coconut (Cocos nucifera L.) zygotic embryos was tested in liquid or solid medium. Percent germination was greater when embryos were cultured in solid
medium, particularly when embryos were placed with their micropyle end facing upwards in relation to the vial orientation,
independently of orientation in relation to gravity. This occurred because solid medium allowed embryos to be positioned with
their micropyle end exposed to the ambient atmosphere of the vial. Germination of embryos facing upwards was suppressed when
the ambient atmosphere was replaced with N2 or when aerobic respiration inhibitors were added to the medium, whereas it was not suppressed when the atmosphere was replaced
with a N2/O2 (50∶50, v/v) mixture, thus indicating that aerobic respiration is required for embryos to germinate. Germination in facing
upwards mode also resulted in improved conversion and plantlet development. These improvements in recovery are important since
they will help to avoid unintentional selection due to low in vitro germination and corresponding conversion of a population subset. These results set the basis for the improvement of current
protocols for in vitro coconut embryo culture, allowing safe movement of germoplasm both in terms of phytosanitation and conservation of genetic
diversity in a population of interest. 相似文献
12.
Summary Anthers ofVitis rupestris du Lot were cultured in vitro at the uninucleate stage of the microspore, in order to investigate the histology of embryogenic and organogenic processes in this genotype. Microspores divided in the anther loculi resulting in the formation of globular structures with a ruptured exine. Somatic embryogenesis and, occasionally, caulogenesis and rhizogenesis occurred in calli produced from all anther tissues except the endothecium. The initial cell of the embryoid was surrounded by a jacket layer when situated deep within the callus. When the embryoid's initial cell was situated in the peripheral callus, a cutinized wall was present and the three-celled proembryoid was almost always segmented, showing the same embryonal type as the zygotic proembryo. Root differentiation and elongation and cap differentiation occurred during the growth phase in liquid medium. The mature root was diarch and contained cells with calcium-oxalate raphides, as seen in vivo. No starch or tannin deposition was ever observed in the mature embryoids.Abbreviations 6-BAP
6-benzylaminopurine
- CC3
Nitsch and Nitsch (1969) basal medium
- CS
cross section
- 2,4-D
2,4-dichlorophenoxy-acetic acid
- LS
longitudinal section 相似文献
13.
The frequency of embryo formation was determined in normal and 5-methyltryptophan-resistant (5-MTr) cell lines of wild carrot (Daucus carota L.) grown in the presence or absence of 2-isopentenyladenine (2-ip) and 2,4-dichlorophenoxyacetic acid (2,4-D). 2-ip stimulated the intitation of embryo formation and also accelerated embryo development. 2.4-D inhibited embryo differentiation at several stages: at 0.1 mg/l, it stopped regeneration at the earliest stage, resulting in callus growth instead of embryo formation; at 0.04 mg/l 2,4-D, some globular embryos were produced, but they did not develop into more advanced embryos. Variant cell lines with higher levels of auxin (indole-3-acetic acid, IAA) were used to study the effect of an elevated endogenous concentration of auxin on embryogenesis. IAA at these concentrations suppressed regeneration in the same manner as the exogenous auxin, 2,4-D, did. This result confirms the hypothesis that high levels of IAA are responsible for the suppression of regeneration in the 5-MTr cell lines. 相似文献
14.
InCocos (and probably in all other palms) the embryogenesis shows a number of primitive characters, such as differentiation of the embryo proper from one cell of the pluricellular proembryo, origin of the single cotyledon from a position lateral to the terminal stem tip, and a tendency to cleavage polyembryony. 相似文献
15.
Brent Tisserat Toshio Murashige 《In vitro cellular & developmental biology. Plant》1977,13(11):799-805
Summary A factor that represses asexual embryogenesis has been observed in the Rutaceae, with particularly high concentrations in
the naturally monoembryonic cultivars. This investigation was an initial step towards identifying the factor.Citrus reticulata Blanco Ponkan mandarin nucellus explants andDaucus carota L. ‘Queen Anne's Lace’ callus were employed to examine effects of known plant growth regulators and to determine possible
identity of one or more of them with the repressive factor. The chalazal halves of ovules ofC. media L. ‘Citron of Commerce’ were used as control repressor source. Embryo initiation and growth of both test tissues were depressed
markedly by 2,4-D, abscisic acid and ethephon. Slight inhibitions were obtained with IAA, kinetin and gibberellic acid. Recovery
from the repressor did not occur readily inCitrus nucellus following recultures in citron-ovule-free medium; carrot callus resumed normal embryogenesis immediately upon transfer
to suppressor-free medium. The repression by natural sources apparently involved the combined action of some or all natural
hormones that are generically related to the above.
This paper is part of B. Tisserat's Ph.D. dissertation in Botany at the University of California, Riverside. The research
was supported in part by the Elvenia J. Slosson Fellowship in Ornamental Horticulture awarded to T. Murashige. 相似文献
16.
Morphogenesis and plant regeneration were analyzed in axenic tissueculture of the red alga Solieria filiformis (Kützing)Gabrielson. Thallus segments cultured in ASP 12-NTA synthetic medium showedgrowth of filaments formed by divisions of cortical, subcortical and medullarycells (filamentous explants), whereas in seawater enriched with Von Stosch'ssolution, thallus segments developed branches. Filamentous explants were abletoregenerate plants when transferred from a solid to a liquid medium. Plantregeneration was significantly promoted by treatment with plant growthregulators on filamentous explants formed from intercalary segments, up to 67plantlets per explant in treatments with 6-benzylaminopurine (5.0 mgl–1), in contrast to three plantlets in controlslackingplant growth regulators. These adventitious plantlets developed into plantsmorphologically similar to those originated from germinating spores. Theseresults indicate that plant growth regulators play a role on the regulation ofmorphogenesis, and could be useful for micropropagation of colloid-producingredalgae. 相似文献
17.
We conducted a study of the cell cycle of coconut palm tissues cultured in vitro in order to regulate regeneration. Coconut palm is a plant for which it is difficult to monitor the ability of the meristematic cells to actively divide. Cell nuclei were isolated from various types of coconut palm tissues with and without in vitro culture. After the nuclei were stained with propidium iodide, relative fluorescence intensity was estimated by flow cytometry. Characterization of the cell cycle reinforced the hypothesis of a block in the G0/G1 and G1/S phases of the coconut cells. A time-course study carried out on immature leaves revealed that this block takes place gradually, following the introduction of the material in vitro. Synchronization of in vitro-cultured leaves cells using 60 µM aphidicholin revealed an increase in the number of nuclei in the S phase after 108 h of treatment. The significance of these results is discussed in relation with the ability of coconut tissue cultured in vitro to divide.Communicated by P. Debergh 相似文献
18.
A. Pech y Aké B. Maust A. Orozco-Segovia C. Oropeza 《In vitro cellular & developmental biology. Plant》2007,43(3):247-253
The effect of gibberellic acid (GA3) was tested on germination of coconut zygotic embryos, their conversion into plantlets and ex vitro survival. There were four treatments consisting of 5 wk of culture in semi-solid medium or liquid medium, with or without
GA3. Embryos were then transferred to GA3 free-liquid medium for the rest of a 32-wk culture. Germination and conversion percentages were higher in semi-solid medium
than in liquid medium, and with both media percentages increased with GA3 treatment (with the exception of the highest GA3 concentration). Embryos of two varieties (MGD and MYD) were used. The following are the results with MGD embryos. Optimum
GA3 concentration in liquid medium was 0.46 μM, with 80% germination (62% in the control without GA3) and 4.6 μM in semi-solid medium with 98% germination (71% in the control). With GA3 treatment, germination was also faster. Conversion in semi-solid medium with GA3 was 87% (60% in the control), and 45% in liquid medium with GA3 (25% in the control). Once the plantlets had at least three bifid leaves and three primary roots at the time of transfer
to ex vitro, they survived independently of the treatment. When MYD embryos were used, germination and conversion percentages were higher
in semi-solid medium than in liquid medium, and they increased when GA3 was used, although percentages were lower than those obtained with MGD embryos. The results showed that the use of GA3 benefited coconut embryos in culture because it favored germination and conversion to plants on semi-solid medium, and hence
improved previous protocols. 相似文献
19.
Summary Androgenesis has been induced in excised anthers of two tetraploid species ofArachis. The pollen underwent various modes of development leading to the formation of pollen-embryos and callus. 相似文献
20.
K. Chengalrayan M. Gallo-Meagher 《In vitro cellular & developmental biology. Plant》2001,37(4):434-439
Summary Sugarcane (Saccharum spp. hybrid cv. CP 84-1198) embryogenic calluses were induced from young leaves cultured on modified Murashige and Skoog
basal medium supplemented with 13.6 μM 2,4-dichlorophenoxyacetic acid. Five concentrations, 0.5, 1.0, 2.5, 5.0, and 10.0 μM, of five different growth regulators, 6-benzylaminopurine, kinetin, 6-γ,γ-(dimethylallylamino)purine, zeatin, and thidiazuron,
were tested with or without 22.5 μM α-naphthaleneacetic acid to compare their ability to induce regeneration from embryogenic callus. After 4 wk on medium, the
percentage of shoot meristem induction was evaluated, and after 10 wk the total number of shoots produced, as well as the
percentage of shoots greater than 1 cm in length, was obtained. Although it had the lowest percentage of elongated shoots,
medium containing thidiazuron alone performed better than all other growth regulators tested, with the highest percentage
of shoot induction and the largest number of shoots, particularly at a concentration of 2.5 μM. 相似文献