scholarly journals Anatomía del desarrollo de la semilla de Hippocratea celastroides

2017 ◽  
pp. 43
Author(s):  
Guadalupe Espinosa-Osornio ◽  
E. Mark Engleman

Embryological studies of Hippocratea are restricted to few species, and they show similarity between Hippocratea and Celastraceae. Nevertheless, differences based on H. grahamii have originate controversy on the taxonomic position of the genus. We have examined the seed development of H. celastroides H.B.K, by ligth microscopy. This specie has anatropous and bitegmic ovules. At anthesis, the micropyle is formed only by the inner integument. In the endotegmen and exotesta there are tannin deposits beginning in early stages. After fertilization, the outer integument increases abundantly, it alone forms the wing. The endosperm development is of the nuclear type. After syngamy the zygote rests for 3 months before dividing. The mesoteste develops aerenquima, which differentiates gradually into tracheoidal cells. One layer of endosperm remains at madurity. The cotyledons are connate and rotate 90°. On the basis of these results, we consider that Hippocratea belongs the Celastraceae.

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Keliang Zhang ◽  
Weizhang Cao ◽  
Jerry M. Baskin ◽  
Carol C. Baskin ◽  
Jing Sun ◽  
...  

Abstract Background Seeds of Paeonia ostii have been proposed as a source of raw material for the production of edible oil; however, lack of information about the developmental biology of the seeds hampers our ability to use them. Our aim was to investigate development of the seed coat, endosperm and embryo of P. ostii in relation to timing of accumulation of nutrient reserves from pollination to seed maturity. Ovules and developing seeds of P. ostii were collected at various stages of development from zygote to maturity. Seed fresh mass, dry mass, germination, moisture, soluble sugars, starch, protein and oil content were determined. Ontogeny of seeds including embryo, endosperm and seed coat were analyzed histologically. Results The ovule of P. ostii is anatropous, crassinucellate and bitegmic. The zygote begins to divide at about 5 days after pollination (DAP), and the division is not accompanied by cell wall formation. By 25 DAP, the proembryo begins to cellularize. Thereafter, several embryo primordia appear at the surface of the cellularized proembryo, but only one matures. Endosperm development follows the typical nuclear type. The seed coat is derived from the outer integument. During seed development, soluble sugars, starch and crude fat content increased and then decreased, with maximum contents at 60, 80 and 100 DAP, respectively. Protein content was relatively low compared with soluble sugars and crude fat, but it increased throughout seed development. Conclusions During seed development in P. ostii, the seed coat acts as a temporary storage tissue. Embryo development of P. ostii can be divided into two stages: a coenocytic proembryo from zygote (n + n) that degenerates and a somatic embryo from peripheral cells of the proembryo (2n → 2n). This pattern of embryogeny differs from that of all other angiosperms, but it is similar to that of gymnosperms.


Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1911-1925
Author(s):  
Paul E Grini ◽  
Gerd Jürgens ◽  
Martin Hülskamp

Abstract The female gametophyte of higher plants gives rise, by double fertilization, to the diploid embryo and triploid endosperm, which develop in concert to produce the mature seed. What roles gametophytic maternal factors play in this process is not clear. The female-gametophytic effects on embryo and endosperm development in the Arabidopsis mea, fis, and fie mutants appear to be due to gametic imprinting that can be suppressed by METHYL TRANSFERASE1 antisense (MET1 a/s) transgene expression or by mutation of the DECREASE IN DNA METHYLATION1 (DDM1) gene. Here we describe two novel gametophytic maternal-effect mutants, capulet1 (cap1) and capulet2 (cap2). In the cap1 mutant, both embryo and endosperm development are arrested at early stages. In the cap2 mutant, endosperm development is blocked at very early stages, whereas embryos can develop to the early heart stage. The cap mutant phenotypes were not rescued by wild-type pollen nor by pollen from tetraploid plants. Furthermore, removal of silencing barriers from the paternal genome by MET1 a/s transgene expression or by the ddm1 mutation also failed to restore seed development in the cap mutants. Neither cap1 nor cap2 displayed autonomous seed development, in contrast to mea, fis, and fie mutants. In addition, cap2 was epistatic to fis1 in both autonomous endosperm and sexual development. Finally, both cap1 and cap2 mutant endosperms, like wild-type endosperms, expressed the paternally inactive endosperm-specific FIS2 promoter GUS fusion transgene only when the transgene was introduced via the embryo sac, indicating that imprinting was not affected. Our results suggest that the CAP genes represent novel maternal functions supplied by the female gametophyte that are required for embryo and endosperm development.


2020 ◽  
Vol 71 (18) ◽  
pp. 5495-5505 ◽  
Author(s):  
Rui Liu ◽  
Shi-Kai Cao ◽  
Aqib Sayyed ◽  
Huan-Huan Yang ◽  
Jiao Zhao ◽  
...  

Abstract C-to-U RNA editing in plant mitochondria requires the participation of many nucleus-encoded factors, most of which are pentatricopeptide repeat (PPR) proteins. There is a large number of PPR proteins and the functions many of them are unknown. Here, we report a mitochondrion-localized DYW-subgroup PPR protein, PPR27, which functions in the editing of multiple mitochondrial transcripts in maize. The ppr27 mutant is completely deficient in C-to-U editing at the ccmFN-1357 and rps3-707 sites, and editing at six other sites is substantially reduced. The lack of editing at ccmFN-1357 causes a deficiency of CcmFN protein. As CcmFN functions in the maturation pathway of cytochrome proteins that are subunits of mitochondrial complex III, its deficiency results in an absence of cytochrome c1 and cytochrome c proteins. Consequently, the assembly of mitochondrial complex III and super-complex I+III2 is decreased, which impairs the electron transport chain and respiration, leading to arrests in embryogenesis and endosperm development in ppr27. In addition, PPR27 was found to physically interact with ZmMORF1, which interacts with ZmMORF8, suggesting that these three proteins may facilitate C-to-U RNA editing via the formation of a complex in maize mitochondria. This RNA editing is essential for complex III assembly and seed development in maize.


1985 ◽  
Vol 27 (2) ◽  
pp. 134-142 ◽  
Author(s):  
J. P. Gustafson ◽  
A. J. Lukaszewski

The early embryo and endosperm development patterns of five annual taxa and three perennial taxa of the genus Secale were analyzed. The results showed that there was considerable variation in the speed of early embryo and endosperm development within the genus Secale, and that the developmental patterns of the annual and perennial taxa overlapped. Comparisons indicated that DNA content per se did not have any influence on the speed of early embryo development or aberrant endosperm nucleus production in either the annual or perennial taxa. However, comparisons between the percent telomeric heterochromatin and the number of embryo cells produced showed a significant positive correlation in the annual taxa, and a nonsignificant correlation in the perennial taxa. There was a positive correlation between the number of aberrant endosperm nuclei and percent telomeric heterochromatin in the annual taxa, while the perennial taxa showed a nonsignificant but negative correlation. The results suggest that percent telomeric heterochromatin has a different effect on early seed development in the annual taxa than in the perennial taxa.Key words: Secale, heterochromatin, DNA content, embryo cell cycle.


2019 ◽  
Author(s):  
Li Wang ◽  
Songlin Zhang ◽  
Chen Jiao ◽  
Zhi Li ◽  
Chonghuai Liu ◽  
...  

Abstract Background Seedlessness in grape ( Vitis vinifera ) is an important commercial trait for both the fresh and drying markets. However, despite numerous studies, the mechanisms and key genes regulating grape seedlessness are mostly unknown. Results In this study, we sequenced the genomes of the V. vinifera seeded cultivar ‘Red Globe’, the seedless cultivar ‘Centennial’, as well as the derived hybrids. Nonsynonymous SNPs were identified and analyzed with respect to published transcriptome data. All the DEGs containing nonsynonymous SNPs were further analyzed in terms of expression patterns, Gene Ontology and pathway enrichment. A potential QTL region associated with seed size was characterized based on SNP indices for both seedless and seeded progeny. Expression analysis of candidate genes during ovule development in multiple seeded and seedless grape cultivars further indicates their potential function in grape seed development. Conclusion In summary, DEGs containing nonsynonymous SNPs were mainly protein kinase, transcription factors, cytochrome P450 and other factors related to seed development, which were mainly involved in biological processes like hormone balance, seed coat and endosperm development, reproductive organ development, oxidation and reduction, senescence and cell death. Based on SNP-index and expression pattern analysis, three genes were further identified as potential seedlessness-related genes. Overall the data cast light on the differences of seed development between seeded and sedless progeny in perspective of both functional variants and expression pattern,which provides valuable candidates for future functional study.


HortScience ◽  
2009 ◽  
Vol 44 (5) ◽  
pp. 1415-1418 ◽  
Author(s):  
Grace Q. Chen ◽  
Louisa Vang ◽  
Jiann-Tsyh Lin

The morphological, physiological, and biochemical changes during seed development of Lesquerella fendleri were investigated from 7 days after pollination (DAP) to desiccation. The entire course of seed development lasted ≈49 days and it can be divided into seven sequential stages (I to VII). During the early stages (I to III, 7 to 21 DAP), seed grew rapidly, showing a dramatic increase in size and fresh weight. They contained ≈75% water. During midmaturation stages (IV to V, 28 to 35 DAP), storage lipids, proteins, and other components of dry weights accumulated at maximum rates. The accumulation curves followed a sigmoidal pattern during seed development. As a result of water loss, fresh weight dropped significantly when seed progressed to late-maturation/desiccation stages (VI to VII, 42 to 49 DAP). The size of the seed decreased slightly and the color changed from green to orange–brown. Seed proteins were also analyzed using SDS-PAGE. Proteins with high molecular weights were prominent in developing seed at early stages (I to III). At Stage IV (28 DAP), proteins with low molecular weight appeared, whereas the high-molecular-weight proteins decreased in proportion. These low-molecular-weight proteins became predominant throughout the remaining stages of seed development. Forty-seven percent of freshly harvested seed at 35 DAP were able to germinate after 7 days incubation. The germination percentage increased to a maximum of 95% at 42 DAP after 7 days incubation. The relationships among seed morphology, reserve synthesis, and germination are discussed.


Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 333
Author(s):  
Keliang Zhang ◽  
Yin Zhang ◽  
Yusong Ji ◽  
Jeffrey L. Walck ◽  
Jun Tao

Lepidium apetalum (Brassicaceae) is an annual or biennial weed widely distributed in Asia and Europe. The outer surface of L. apetalum seeds produces a large amount of mucilage. The primary aim of this study was to explore the dormancy characteristics and to determine how mucilage develops. The role of mucilage in water absorption/dehydration, the effects of after-ripening, gibberellin acid (GA3), cold stratification and seed coat scarification on germination, the role of mucilage in germination and seedling growth during drought, and the progress of mucilage production during seed development were investigated. The results indicate that the best temperature regime for germination was 10/20 °C. After-ripening, GA3 and seed coat scarification helped to break dormancy. Light promoted germination. Seedling growth of mucilaged seeds were significantly higher than those of demucilaged seeds at −0.606 and −1.027 MPa. Anatomical changes during seed development showed that mucilage was derived from the outer layer of the outer integument cells. Our findings suggest that seeds of L. apetalum exhibited non-deep physiological dormancy. The dormancy characteristics along with mucilage production give seeds of L. apetalum a competitive advantage over other species, and thus contribute to its potential as a weed. Effective control of this weed can be achieved by deep tillage.


Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1794
Author(s):  
Ilya Kirov ◽  
Maxim Dudnikov ◽  
Pavel Merkulov ◽  
Andrey Shingaliev ◽  
Murad Omarov ◽  
...  

The intergenic space of plant genomes encodes many functionally important yet unexplored RNAs. The genomic loci encoding these RNAs are often considered “junk”, DNA as they are frequently associated with repeat-rich regions of the genome. The latter makes the annotations of these loci and the assembly of the corresponding transcripts using short RNAseq reads particularly challenging. Here, using long-read Nanopore direct RNA sequencing, we aimed to identify these “junk” RNA molecules, including long non-coding RNAs (lncRNAs) and transposon-derived transcripts expressed during early stages (10 days post anthesis) of seed development of triticale (AABBRR, 2n = 6x = 42), an interspecific hybrid between wheat and rye. Altogether, we found 796 lncRNAs and 20 LTR retrotransposon-related transcripts (RTE-RNAs) expressed at this stage, with most of them being previously unannotated and located in the intergenic as well as intronic regions. Sequence analysis of the lncRNAs provide evidence for the frequent exonization of Class I (retrotransposons) and class II (DNA transposons) transposon sequences and suggest direct influence of “junk” DNA on the structure and origin of lncRNAs. We show that the expression patterns of lncRNAs and RTE-related transcripts have high stage specificity. In turn, almost half of the lncRNAs located in Genomes A and B have the highest expression levels at 10–30 days post anthesis in wheat. Detailed analysis of the protein-coding potential of the RTE-RNAs showed that 75% of them carry open reading frames (ORFs) for a diverse set of GAG proteins, the main component of virus-like particles of LTR retrotransposons. We further experimentally demonstrated that some RTE-RNAs originate from autonomous LTR retrotransposons with ongoing transposition activity during early stages of triticale seed development. Overall, our results provide a framework for further exploration of the newly discovered lncRNAs and RTE-RNAs in functional and genome-wide association studies in triticale and wheat. Our study also demonstrates that Nanopore direct RNA sequencing is an indispensable tool for the elucidation of lncRNA and retrotransposon transcripts.


2003 ◽  
Vol 51 (5) ◽  
pp. 555 ◽  
Author(s):  
Toshihiro Yamada ◽  
Ryoko Imaichi ◽  
Nallamilli Prakash ◽  
Masahiro Kato

Development of ovules of Illicium anisatum (Illiciaceae), Trimenia moorei (Trimeniaceae), and Austrobaileya scandens (Austrobaileyaceae) (Austrobaileyales) was observed. In Austrobaileya scandens and Trimenia moorei the outer integument is hood-shaped, while it is cup-shaped in Illicium anisatum. On the basis of a phylogeny, the ovule with the hood-shaped outer integument is suggested to be primitive in Austrobaileyales. Seed development of Austrobaileyales was also examined. In Austrobaileya scandens the seed is mesotestal, ruminated, not pachychalazal, and has a micropyle–hilum complex. In Trimenia moorei the seed is exotestal, perispermous, not pachychalazal, and has a micropyle–hilum complex and a circular cap. The seed of Illicium anisatum is exotestal, not pachychalazal, and has a circular cap. Taking the character states of other basal angiosperms into account, primitive seeds of angiosperms are inferred to have such characters as the unilayered exotestal mechanical tissue, circular cap, micropyle–hilum complex and non-pachychalazy. The inferred primitive seed is very simple, suggesting that a great diversity of seeds is established through elaboration of organs/tissues of seeds, and not through reduction as hypothesised previously.


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