Faculty Opinions recommendation of Transporter SlSWEET15 unloads sucrose from phloem and seed coat for fruit and seed development in tomato.

Author(s):  
John Patrick
Keyword(s):  
2021 ◽  
Vol 62 (1) ◽  
Author(s):  
Chih-Hsin Yeh ◽  
Kai-Yi Chen ◽  
Yung-I. Lee

Abstract Background Vanilla planifolia is an important tropical orchid for production of natural vanilla flavor. Traditionally, V. planifolia is propagated by stem cuttings, which produces identical genotype that are sensitive to virulent pathogens. However, propagation with seed germination of V. planifolia is intricate and unstable because the seed coat is extremely hard with strong hydrophobic nature. A better understanding of seed development, especially the formation of impermeable seed coat would provide insights into seed propagation and conservation of genetic resources of Vanilla. Results We found that soaking mature seeds in 4% sodium hypochlorite solution from 75 to 90 min significantly increased germination. For the culture of immature seeds, the seed collection at 45 days after pollination (DAP) had the highest germination percentage. We then investigated the anatomical features during seed development that associated with the effect of seed pretreatment on raising seed germination percentage. The 45-DAP immature seeds have developed globular embryos and the thickened non-lignified cell wall at the outermost layer of the outer seed coat. Seeds at 60 DAP and subsequent stages germinated poorly. As the seed approached maturity, the cell wall of the outermost layer of the outer seed coat became lignified and finally compressed into a thick envelope at maturity. On toluidine blue O staining, the wall of outer seed coat stained greenish blue, indicating the presence of phenolic compounds. As well, on Nile red staining, a cuticular substance was detected in the surface wall of the embryo proper and the innermost wall of the inner seed coat. Conclusion We report a reliable protocol for seed pretreatment of mature seeds and for immature seeds culture based on a defined time schedule of V. plantifolia seed development. The window for successful germination of culturing immature seed was short. The quick accumulation of lignin, phenolics and/or phytomelanins in the seed coat may seriously inhibit seed germination after 45 DAP. As seeds matured, the thickened and lignified seed coat formed an impermeable envelope surrounding the embryo, which may play an important role in inducing dormancy. Further studies covering different maturity of green capsules are required to understand the optimal seed maturity and germination of seeds.


2021 ◽  
Author(s):  
Chih-Hsin Yeh ◽  
Kai-Yi Chen ◽  
Yung-I Lee

Abstract Background: Vanilla planifolia is an important tropical orchid for production of natural vanilla flavor. Traditionally, V. planifolia is propagated by stem cuttings, which produces identical genotype that are sensitive to virulent pathogens. However, sexual propagation with seed germination of V. planifolia is intricate and unstable because of the extremely hard seed coat. A better understanding of seed development, especially the formation of impermeable seed coat would provide insights into seed propagation and conservation of genetic resources of Vanilla.Results: We found that soaking mature seeds in 4 % sodium hypochlorite solution from 75 to 90 min significantly increased germination and that immature seeds collected at 45 days after pollination (DAP) had the highest germination percentage. We then investigated the anatomical features during seed development that associated with the effect of seed pretreatment on raising seed germination percentage. The 45-DAP immature seeds have developed globular embryos and the thickened non-lignified cell wall at the outermost layer of the outer seed coat. After 60 DAP, the cell wall of the outermost layer of the outer seed coat became lignified and finally compressed into a thick envelope. These features matches the significant decreases of immature seed germination percentage after 60 DAP. Conclusion: We report a reliable protocol for seed pretreatment of mature seeds and for immature seeds culture based on a defined time schedule of V. plantifolia seed development. The thickened and lignified seed coat formed an impermeable envelope surrounding the embryo, and might play an important role in seed dormancy of V. plantifolia.


2003 ◽  
Vol 81 (6) ◽  
pp. 531-540 ◽  
Author(s):  
Gurusamy Chinnasamy ◽  
Arya Kumar Bal

The developmental patterns of seed, seed coat, and hardseededness were studied in naturally growing crop plants of beach pea (Lathyrus maritimus (L.) Bigel.) at six reproductive growth stages (S1–S6). Grass pea (Lathyrus sativus L.) seeds were used for comparison in some experiments. The accumulation of fresh and dry weight in pod shell and seed of beach pea and pod shell of grass pea followed an almost sigmoidal pattern. However, grass pea seed showed a linear pattern of weight accumulation. During maturation, moisture content of pod shells and seeds decreased because of dehydration. Beach pea seeds were able to germinate precociously at S4. Seeds collected between S1 and S3 failed to germinate because of immaturity, whereas the development of hard seed coats prevented germination in seeds gathered at S5 and S6. An imbibition test revealed that hardseededness completely prevented water absorption of S5 and S6 seeds even after 24 days of soaking. In grass pea, precocious seed germination was observed at S3. However, speed of germination, germination percentage, seedling length and dry weight increased as seeds approached maturity. Lipid and protein accumulation in seeds of both species increased progressively with maturity and showed a positive correlation with seed weight accumulation. In both beach pea and grass pea seeds, S6 was identified as a physiological maturity stage.Key words: beach pea, grass pea, hard seed, imbibition, Lathyrus, seed coat, seed development, water impermeability.


1957 ◽  
Vol 35 (2) ◽  
pp. 139-153 ◽  
Author(s):  
Hugh P. Bell

Seed development was followed from fertilization to maturity. Pollen tubes required about 4 days to grow from stigma to ovule. In some plants, particularly bagged ones, nucellar cells remained alive and contents of the embryo sac degenerated. Many ovules did not develop. Seeds were counted and sorted in a random representative collection of 1075 berries. The average number of seeds per berry was 64.2. Of these 49.9 (or 77.7%) were imperfect. More complete pollination increased the percentage of normally developing ovules. Development of perfect seeds followed a familiar pattern. Unfamiliar features were noted as follows: 1. Degeneration of cells at both micropylar and chalazal ends resulted in a homogeneous plasma. This plasma formed strands across haustoria and almost completely surrounded the zygote. 2. Micropylar endosperm cells formed a dense plug. Developing embryos may have had difficulty in penetrating this plug. 3. Many embryos had died at some stage of development. 4. A conspicuous integumentary tapetum was present until the endosperm was about half its final size.Embryo development was the "soland" type. Mature seeds were "axile linear". Imperfect seeds were chiefly of two types: (a) medium sized and solid with middle integumentary layers lignified, or (b) small and collapsed with all tissues inside seed coat disintegrated. No imperfect seed had an embryo.


2005 ◽  
Vol 17 (3) ◽  
pp. 876-887 ◽  
Author(s):  
Satoru Nakaune ◽  
Kenji Yamada ◽  
Maki Kondo ◽  
Tomohiko Kato ◽  
Satoshi Tabata ◽  
...  

2020 ◽  
Author(s):  
Deirdre Khan ◽  
Dylan J. Ziegler ◽  
Jenna L. Kalichuk ◽  
Vanessa Hoi ◽  
Nina Hyunh ◽  
...  

AbstractWe profiled the gene regulatory landscape of Brassica napus reproductive development using RNA sequencing. Comparative analysis of this nascent amphidiploid across the plant lifecycle revealed the contribution of each subgenome to plant reproduction. Global mRNA profiling revealed lower accumulation of Cn subgenome transcripts relative to the An subgenome. Subgenome-specific transcriptional networks identified distinct transcription factor families enriched in each of the An and Cn subgenome early in seed development. Global gene expression profiling of laser-microdissected seed subregions further reveal subgenome expression dynamics in the embryo, endosperm, and seed coat of early stage seeds. Transcription factors predicted to be regulators encoded by the An subgenome are expressed primarily in the seed coat whereas regulators encoded by the Cn subgenome were expressed primarily in the embryo. Data suggest subgenome bias are characteristic features of the B. napus seed throughout development, and that such bias might not be universal across the embryo, endosperm, and seed coat of the developing seed. Whole genome transcription factor networks identified BZIP11 as a transcriptional regulator of early B. napus seed development. Knockdown of BZIP11 using RNA interference resulted in a similar reduction in gene activity of predicted gene targets, and a reproductive-lethal phenotype. Taken together, transcriptional networks spanning both the An and Cn genomes of the B. napus seed can identify valuable targets for seed development research and that-omics level approaches to studying gene regulation in B. napus can benefit from both broad and high-resolution analyses.One Sentence SummaryGlobal RNA sequencing coupled with laser microdissection provides a critical resource to study subgenome bias in whole seeds and specific tissues of polyploid plants.


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.


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.


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