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1.
Extensins are cell wall basic glycoproteins with a polypeptide backbone that is extremely rich in hydroxyproline. In this paper, the function of extensins in embryo development was studied in Nicotiana tabacum. By using Western blot and immunohistochemistry, the extensin JIM20 epitopes were found to express in different developmental stages of embryos, and specifically in the top of the embryo proper (EP) and the suspensor of the late globular embryos. In order to clarify the functions of extensins, a potent hydroxyproline synthesis inhibitor, 3,4-dehydro-L-proline (3,4-DHP), was used in ovule and embryo culture. The results showed that the addition of 3,4-DHP caused abnormal embryos with single, asymmetry and supernumerary cotyledon primordia, and continuous culture led to cotyledon defects in the germinated seedlings. Histological sections showed that the shoot apical meristem (SAM) of the abnormal seedlings was dissimilar from the controls, especially in the seedlings with cup-shaped cotyledons. Furthermore, the vasculature of the abnormal cotyledons was in an out-of-order format and contained at least two main veins. Finally, both the hydroxyproline assay and fluorescent immunolocalization confirmed that 3,4-DHP treatment reduced the level of extensins in the cultured ovules and embryos. These results indicate that extensins may play important roles in the cotyledon primordium formation, SAM activity, and vasculature differentiation during embryo development. 相似文献
2.
Rapid propagation of Eleutherococcus senticosus via direct somatic embryogenesis from explants of seedlings 总被引:5,自引:0,他引:5
Explants from three different parts (cotyledon, hypocotyl or root) of one week-old seedlings of Eleutherococcus senticosus were cultured on Murashige and Skoog (MS) medium with 1.0 mg l-1 2,4-D. Somatic embryos were formed directly from the surfaces of explants. The frequency of direct somatic embryo formation
was the highest in the hypocotyl segments (75%) as compared to cotyledon (56%) or root segments (12%). When hypocotyl explants
from 3 different stages of seedlings (zero, one or three week-old) were cultured on MS medium with 1.0 mg l-1 2,4-D, the frequency of somatic embryo formation rapidly declined as the zygotic embryos germinated. However most somatic
embryos (93%) from explants of zygotic embryos developed as fused state (multiple embryo), whereas somatic embryos (over 89%)
from more developed seedlings developed into single state (single embryo). Single embryos germinated and regenerated into
plantlets with both shoots and roots, while multiple embryos only regenerated into only multiple shoots. Plantlets that regenerated
from single embryos of E. senticosus were acclimatized in a greenhouse.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
3.
Seied Ali Hosseini Tafreshi Mansour Shariati Mohammad Reza Mofid Mojtaba Khayam Nekui 《In vitro cellular & developmental biology. Plant》2011,47(5):561-568
A highly promising procedure to obtain seedlings of Taxus baccata L. has been developed, which involves a combination of in vitro embryo culture and growth under hydroponic conditions. Embryos isolated from freshly collected seeds were 100% sterile, even
though the seeds were not treated with acid or soaked in water prior to culturing. The embryo germination level of non-leached
seeds was slightly lower (85%) than those leached in running water for 7 d (100%). The leached embryos germinated with extended
roots while the non-leached embryos had abnormal shapes. The embryos cultured on media supplemented with an absorbent (PVP
or activated charcoal) had extended roots and shoots and were a larger size without any browning, as compared to those grown
without the supplement; activated charcoal gave better results. There were no significant differences in germination rates
of T. baccata embryos between the media with differing strengths of macronutrients; however, for further development of the shoot, it was
necessary to sub-culture the seedlings in MS in the light. To obtain seedlings with longer roots, they had to be maintained
in one-half strength MS in darkness. Approximately 90% of the plants survived when grown hydroponically for 2 mo. The surviving
plants showed well-extended roots and were a good starting material for genomic, proteomic, and conservational studies as
well as Taxol permeabilization investigations. 相似文献
4.
Tere Flores Laura J. Wagner Hector E. Flores 《In vitro cellular & developmental biology. Plant》1993,29(4):160-165
Summary We have previously shown (Flores and Sgrignoli, 1991) that immature embryos ofTaxus brevifolia andT. X media are capable of precocious germination and can grow into seedlings in vitro. The cultural and environmental parameters for
embryo germination and conversion into seedlings have been optimized and extended toT. baccata andT. cuspidata. A 14-h photoperiod improved embryo germination and growth into seedlings. A pregermination cold treatment of the seeds had
a positive effect on both the onset and percentage of germination. Embryos from cold-treated seeds germinated earlier and
at a higher frequency than those from control seeds. Boron was necessary for embryo germination, and levels of this micronutrient
were established for optimal growth and germination ofT. brevifolia andT. X media cv. Hicksii embryos. Gupta and Durzan’s medium was superior to White’s for embryo germination and root formation. Naphthaleneacetic
acid stimulated root formation in embryo-derived seedlings. We also found that immature embryos could be induced to form callus
with embryogenic potential. Taxol and related taxanes were detected in embryo- derived seedlings. 相似文献
5.
The embryo-defective (emb) mutants of Arabidopsis constitute a large and diverse group of mutants disrupted in a broad range of embryonic processes, including morphogonesis, cell differentiation, and maturation programs. This report describes a subset of these mutants, the late embryo defectives, which develop beyond the globular stage of embryogenesis but fail to complete normal morphogenesis. A representative sample of 12 late mutants was chosen for this study, patterns of morphogenesis were characterized, the germination potential of mutant seeds was investigated, and additional mutant alleles within the collection were identified. Morphological defects in mutant embryos became apparent during the heart stage of development, when embryos normally begin the rapid cell division and expansion required for the completion of morphogenesis. Despite their morphological abnormalities, mutant embryos often germinated from dry seed, demonstrating that genetic programs required for the establishment of desiccation tolerance remained intact. Mutant seedlings displayed a wide range of developmental abnormalities, including altered morphology, lack of pigmentation, dwarfism, and disorganized vegetative growth. One late mutant was found to be allelic to an early embryo defective that arrests at the globular stage. These results suggest that a number of late EMB genes encode basic cellular and metabolic functions needed for cell division, enlargement, and embryonic growth. The rapid growth and metabolic changes that occur at the heart stage may present a barrier to normal development in the late mutants, resulting in altered embryo morphology and other developmental defects. It is proposed that many Arabidopsis mutants with abnormal embryo and seedling morphology are not defective in the regulation of pattern formation or morphogenesis, but rather in fundamental physiological and cellular processes required for the completion of normal growth and development. © 1995 Wiley-Liss, Inc. 相似文献
6.
Factors affecting somatic embryogenesis in peanut (Arachis hypogaea L.) using leaflet explants of seedlings obtained from aseptically germinated embryo axes were evaluated. Somatic embryogenesis
was influenced by developmental stage, leaflet size, induction medium, and time on induction medium. Leaflets that were 5–7
mm long had a greater embryogenic response than smaller or larger leaflets. Percent embryogenesis and mean number of embryos
were related to the developmental stage of germinating seedlings. A greater response was obtained if leaflets were folded
and closely appressed. Preselection of leaflets increased percent embryogenesis from 21% up to 67%. As leaflets unfolded,
embryogenesis decreased; open leaflets lost the potential for embryogenesis. The optimal induction conditions were a 7-day
incubation period on Murashige and Skoog medium with 136 μm 2,4-dichlorophenoxyacetic acid and 0.93 μm kinetin. Somatic embryos germinated to form plants that exhibited a normal morphology.
Received: 29 December 1997 / Revision received: 9 April 1998 / Accepted: 24 April 1998 相似文献
7.
John Statton Gary A. Kendrick Kingsley W. Dixon Marion L. Cambridge 《Restoration Ecology》2014,22(2):196-203
Seed represents a potentially ecologically sustainable source of planting units for restoring seagrasses, particularly for seagrasses where transplanting negatively impacts donor beds. However, newly germinated seeds may be nutrient limited as their underdeveloped root systems may constrain capacity to access sediment‐based resources. We conducted a study in land‐based aquaculture tanks to determine whether early growth of newly germinated Posidonia australis seedlings could be enhanced by adding inorganic nutrients to the sediment. Sediments were supplemented with nitrogen and phosphorus in a factorial design (no nutrients, N, P, N + P). Shoot survival, whole shoot biomass, root morphology, root architecture, and nutrient concentration of seedlings were assessed monthly for the first 4 months after germination. More than 90% of seedlings survived during the 4 months of the experiment, irrespective of nutrient treatment. Growth of P. australis seedlings was not enhanced by addition of N or P to the sediment despite nutrient uptake occurring. Seedling growth was found to be more dependent on seed nutrient reserves rather than external nutrient sources for at least the first 4 months after germination. Adding inorganic nutrients to the sediment also significantly reduced the development of the seedling root system in terms of biomass, length, and density of lateral root branches. This study demonstrated that inorganic nutrient supplements constrain root development and therefore capacity for successful anchorage of seagrass seedlings, and pose a significant limitation on seedling establishment when transferred to the field, as well as potentially limiting natural and transplanted seedling establishment in eutrophic sediments. 相似文献
8.
Influence of substrate and burial on the development of Posidonia oceanica: implications for restoration
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Laura Guerrero‐Meseguer Carlos Sanz‐Lázaro Krittawit Suk‐ueng Arnaldo Marín 《Restoration Ecology》2017,25(3):453-458
Posidonia oceanica is one of the few seagrasses that can colonize hard and soft substrates. To test whether substrate could affect root development of the seedlings, with a legacy effect upon transplantation to sand, we germinated seeds on hard (glass slide) versus soft (sand) substrates in microcosms. We found that sand favored root system development, with a compensatory slowing of leaf development, while glass had the opposite effect. After 4 months, we transplanted all seedlings to sand and tested for a legacy effect of initial substrate type. Leaves of seedlings germinated on sand and glass slides reached approximately the same length, but roots from seedlings germinated on glass did not develop fully. Seed burial (0–1.5 cm) did not affect seedling development. These results suggest that the culture of P. oceanica on sand prior to transplantation could enhance seedlings survival in restoration programs. 相似文献
9.
Hector E. Flores Paula J. Sgrignoli 《In vitro cellular & developmental biology. Plant》1991,27(3):139-142
Summary The lengthy dormancy requirement of yew seeds can be overcome with a simple in vitro method. Viable embryos were excised from
seeds ofTaxus brevifolia and four cultivars ofT. media over a range of developmental stages. Embryos were cultured in several basal media formulations (Whites’, Gamborg’s B5 and
Murashige and Skoog’s) under dark or light. After a lag period of 1 to 2 wk, embryos of both species germinated precociously.
Germination rates of up to 70% were obtained withT. media cv. Hicksi embryos. The highest rates of germination were obtained in White’s and MS media. Embryos excised from green seeds
with undeveloped arils showed the highest germination rates. As the seeds approached maturity, in vitro germination rates
of the excised embryos declined dramatically. Green seeds and seeds with developing arils could be stored at 5° C without
large loss in embryo germination. Seeds with fully developed arils could be stored frozen at −20° C for 1 wk while still allowing
about 50% of embryo germination. At least 30% of the precociously germinated embryos of both species were able to develop
into full seedlings. Our method appears to be generally applicable toTaxus spp.
This research was supported by a grant from the Hawaii Biotechnology Group, Inc. 相似文献
10.
Improved efficiency in apricot breeding: Effects of embryo development and nutrient media on in vitro germination and seedling establishment 总被引:3,自引:0,他引:3
Apricot (Prunus armeniaca L.) embryos at three stages of development were cultured on C2d, SBH and WPM media. In vitro culture produced high percentages of germination and seedlings throughout all three developmental stages. Significant media effects were noted for changes in both embryo length and weight during the culture period, as well as number of plants produced. Embryos between 5 and 9 mm (developmental stage I) germinated and developed into plants in a significantly higher percentage than in the other two more mature stages. Therefore, embryo culture can be successfully used as a tool in an apricot breeding program to obtain higher percentages of seedlings from planned hybridization or to overcome a lack of seed germination. 相似文献
11.
Dark pretreatment improves adventitious shoot organogenesis from cotyledons of diploid watermelon 总被引:6,自引:0,他引:6
The influence of light incubation during embryo germination on shoot organogenesis from cotyledons of four diploid watermelon
[Citrullus lanatus (Thumb.) Matsum. & Nakai cultivars was examined. Germinating embryos in darkness significantly improved the number of explants
that produced harvestable shoots during the 6 week incubation period on shoot regeneration medium under a 16-h photoperiod.
The percentage of explants with shoots more than doubled for `Crimson Sweet' and was about 1.5-fold greater for `Sweet Gem'
and `Yellow Doll' when embryos were germinated in darkness. The percentage of explants with shoots was not significantly improved
for `Minilee' by pretreating seedlings in darkness. This study demonstrates that optimal shoot regeneration can be obtained
by germinating embryos in darkness before preparing cotyledon explants.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
12.
远缘杂交无论在植物遗传学理论的建立还是在新品种的培育上都是一项十分有用的技术,特别在小麦上成绩更为突出。近来发现小麦不但和其亲缘属(如山羊草属、偃麦草属,赖草属等)植物可以杂交,而且和亲缘关系较远的植物种属如玉米、珍珠栗、大刍草、摩擦禾等杂交也有很高的成胚率,并且通过杂种胚发育过程中父本染色体的消失,可以获得小麦单倍体。Laurie和Bennett以高粱属的 相似文献
13.
14.
Michael R. Becwar Thomas L. Noland Judith L. Wyckoff 《In vitro cellular & developmental biology. Plant》1989,25(6):575-580
Summary Quantitative data are presented on the efficiency of three stages of plant regeneration from somatic embryos of Norway spruce
(Picea abies L.): 1) Maturation, the development of immature embryos to the cotyledonary stage; 2) Germination, primary root growth; and
3) Conversion, plantlet survival and continued growth in nonaxenic conditions. Maturation frequency was calculated relative
to the number of immature somatic embryos induced to develop on the basal medium of von Arnold and Eriksson (1981). The average
number of immature somatic embryos was 700 per gram of embryogenic callus, on medium supplemented with ABA and IBA (1 μM each).
Maturation was the least efficient stage of regeneration; an average of 3% of the embryos induced to develop reached the cotyledonary
stage. Mean germination frequencies were improved on treatments which avoided immersion of the radicle in medium solidified
with agar. Whereas, 27% of the somatic embryos germinated when radicles were immersed in agar medium, 45% germinated when
placed on the surface of the medium, and 56% germinated when cotyledons were immersed in agar medium and the culture vessel
inverted. Twenty-nine percent of the somatic embryos germinatedin vitro were converted to plants. Under greenhouse conditions these plants set dormant buds, subsequently survived overwintering
(to −5°C), and renewed vegetative growth synchronously with seedlings grown under the same conditions. Our results verified
long-term (2 year) growth and development potential of conifer somatic embryo plants. 相似文献
15.
Morphological and anatomical features of mature embryos and seedlings were observed at different growth stages in the parasitic
angiospermCuscuta japonica Choisy. The spirally coiled embryos from scarified seeds had no cotyledons but possessed blunt radicles. Seeds germinated
at 30°C in the dark. Although most embryo cells incubated for 16 h did not have starch grains, the shoot cells of three-day-old
seedlings possessed numerous starch grains. After these seedlings were transferred to a lightened growth chamber, all the
shoot apical regions of seedlings grown for 6,8, and 10 days became greenish and hooked. Most of the shoot cells, including
the green apical parts, contained abundant starch grains. The hooks opened only when one seedling made contact with another
seedling. This suggested that the green and hooked shoot apical regions played an important role in searching for and twining
about their host plants. In some two-day-old seedlings, the massive roots were circular or semi-circular. This enabled the
shoot axes to stand erect on some substratum. It would assist the shoots in making contact with the host plant. In eight-day-old
seedlings, the green apical regions also were hooked and the roots were considerably degraded. 相似文献
16.
Mendes-Rodrigues C Carmo-Oliveira R Talavera S Arista M Ortiz PL Oliveira PE 《Plant biology (Stuttgart, Germany)》2005,7(5):533-540
Apomixis and adventitious polyembryony have been reported for several species of Bombacoideae, including Eriotheca pubescens, a tree species of the Neotropical savanna (Cerrado) areas in Brazil. However, the origin of polyembryonic seeds and their importance for the reproduction of the species remained to be shown. Here, we analyzed the early embryology of this species to establish the apomictic origin of extranumerary embryos. We also observed the geographic distribution of polyembryony in E. pubescens, and tested if apomixis was related to the source of pollen (self or cross) and population density. Moreover, we tested if polyembryonic apomictic embryos would develop normally into seedlings. In the observed seed primordia, after a relatively long quiescent period, the zygote developed into a sexual embryo concurrently with adventitious apomictic embryos which developed from nucellus cells. Adventitious embryos develop faster than sexual ones and are morphologically similar, so that 44 days after anthesis it was virtually impossible to distinguish and trace the fate of the sexual embryo. Polyembryony is widely distributed in populations some 400 km distant, and only one strictly monoembryonic individual was observed during the study. The number of embryos per seed varied between fruits and individuals but was significantly higher in seeds from cross-pollinations than from selfs, although fruit and seed set after crosses were much lower than after selfs. Embryo development into seedlings depended on their weight at germination, but polyembryonic seeds germinated and produced up to seven seedlings per seed in greenhouse conditions. Adventitious embryony and apomictic seedlings would explain the mostly clonal populations suggested by molecular studies. 相似文献
17.
The induction of seedlings with multiple shoots by the in vivo treatment of embryos of wheat by herbicides such as 2,4-D, 2,4,5-T, MCPA and TBA as well as mixtures of these substances was studied. Treatment during the first week of embryo development was necessary for the production of additional shoots in the seedling; later treatment gave rise to callused seedlings. Other seedlings such as oats, barley and rye, and other species of wheat were treated, but seedlings with extra shoots were not produced, though callused seedlings were recovered. 相似文献
18.
García J.L. Troncoso J. Sarmiento R. Troncoso A. 《Plant Cell, Tissue and Organ Culture》2002,69(1):95-100
The influence of sucrose or mannitol on in vitro zygotic embryo germination, seedling development and explant propagation of olive tree (Olea europaea L.) was compared. Embryos germinated without sucrose in the medium but for adequate development of the seedlings to yield viable plants, a carbohydrate supply was necessary; both sucrose and mannitol were equally suitable for this purpose. However, when explants obtained from in vitro germinated embryos were cultured with mannitol or sucrose, then the polyalcohol promoted significantly more growth than sucrose by increasing shoot length, pairs of leaves formed, and breaking apical dominance. This improved the in vitro culture of olive plant material, thus allowing new olive clonal lines to be obtained in shorter times. This will assist in future breeding experiments with the species. 相似文献
19.
A convenient and reliable method for culturing cotton embryos is needed to obtain interspecific hybrids of this genus. C.A. Beasley and I.P. Ting (Amer. J. Bot. 60, 130, 1973) developed a phytohormone-supplemented medium (BTP) upon which the growth of ovules was similar that of in situ ovules. This medium was examined for in-ovulo embryo culture. Although good ovule growth occurred on BTP no embryos developed to maturity. However, when the medium was supplemented with NH
4
+
, more than 50% of the ovules produced mature embryos, and many of these germinated precociously after 8–10 weeks of culture. After germination seedlings were established on a separate medium designed to give balanced root and shoot growth. Subsequently young plants could be transferred to pots for greenhouse culture. 相似文献
20.
M. Rambabu M. Upender D. Ujjwala T. Ugandhar M. Praveen N. Rama Swamy 《In vitro cellular & developmental biology. Plant》2006,42(5):418-421
Summary This study reports a protocol for germination of Givotia rottleriformis (var. Tel. Thella Poniki) using zygotic embryo culture. A 100% germination was obtained by culturing the embryos on Murashige
and Skoog medium containing 30 gl−1 sucrose. A sucrose concentration lower or higher than 30 gl−1 resulted in lower germination or promoted callus formation. The seedling growth was promoted by the addition of 100 mgl−1 tyrosine in the medium. Seedlings germinated in the presence of 0.2–0.4 mgl−1 α-naphthaleneacetic acid and 0.3–0.5 mgl−1 indole-3-butyric acid were abnormal, showing a slender stem with slender roots or forming callus with stout roots. Germination
also affected embryo orientation in culture; placing embryos upright on the medium was most beneficial for germination. The
in vitro-germinated seedlings were acclimatized in soil under shady conditions with a survival rate of 60–70%. These plants
were phenotypically normal, healthy, and similar to donor plants. This protocol will be useful for overcoming seed dormancy
and for rapid multiplication and conservation of G. rottleriformis using zygotic embryo culture. 相似文献