Functions and regulation of β-1,3-glucanases during seed germination, dormancy release and after-ripening

2003 ◽  
Vol 13 (1) ◽  
pp. 17-34 ◽  
Author(s):  
Gerhard Leubner-Metzger
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Environmental Factors ◽  
Direct Evidence ◽  
Class I ◽  
Dormancy Release ◽  
Endosperm Weakening ◽  
Key Factor ◽  
Radicle Emergence ◽  
Micropylar Endosperm

Abstractβ-1,3-Glucanase (βGlu) expression in seeds plays important roles in the regulation of seed germination, dormancy and in the defence against seed pathogens. A thick β-1,3-glucan layer is typical for the seed envelope of cucurbitaceous species, confers seed semipermeability and is degraded during germination. In many species with coat-imposed dormancy, the seed envelope confers a physical constraint to radicle emergence. In the solanaceous species, the micropylar endosperm and testa have this function, and endosperm weakening appears to be a prerequisite for germination. Class I βGlu is transcriptionally induced in the micropylar endosperm of tobacco, tomato and other solanaceous seeds just prior to radicle emergence. βGlu induction and germination are tightly linked in response to plant hormones and environmental factors, e.g. they are both promoted by gibberellins and inhibited by abscisic acid (ABA). Sense and antisense transformation of tobacco reveals two sites of βGlu action: after-ripening-mediated release of testa-imposed dormancy and endosperm rupture during germination. The use of an ABA-inducible chimeric sense-transgene resulted in overexpression of class I βGlu in seeds and provided direct evidence that βGlu contributes to endosperm rupture. A model integrating βGlu, seed dormancy, after-ripening and germination is presented, and possible mechanisms for βGlu action are discussed. It is proposed that βGlu not only helps defend seeds against pathogens, but is also a key factor in regulating coat-imposed dormancy and germination of seeds in response to environmental and hormonal cues.

scholarly journals Effect of stratification and gibberellic acid on epicotyl dormancy release in seeds of Yunnanopilia longistaminea (Opiliaceae)

2016 ◽  
Author(s):  
Guan-song Yang ◽  
Liu Yang ◽  
Yue-hua Wang ◽  
Shi-kang Shen
Keyword(s):  
Seed Germination ◽  
Gibberellic Acid ◽  
Economic Value ◽  
Cold Stratification ◽  
Dormancy Release ◽  
Spring Temperature ◽  
Edible Plant ◽  
Seed Moisture Content ◽  
Radicle Emergence ◽  
Shoot Emergence

Yunnanopilia longistaminea is an endangered monotypic species belonging to Opiliaceae. This edible plant is an important germplasm source with a high economic value in China. The seed dormancy and germination of Opiliaceae species have been rarely investigated. This study examined the effects of scarification, soaking in gibberellic acid, and dehydration on the seed germination of Y. longistaminea. Results indicated that the seed germination of this species involves two stages: radicle emergence and epicotyls (shoot) emergence. During radicle emergence, the optimum temperatures were 28 °C and 28 °C/20 °C. Seed moisture content and viability decreased as dehydration occurred. Thus, the seeds may be recalcitrant. The optimum GA3 solution for the seeds undergoing shoot emergence was 100 mg·L−1. The percentages of shoot emergence in 7 and 14 days of stratification at 5 °C were slightly higher than those in other groups. This study is the first to describe epicotyl dormancy in Y. longistaminea seeds. From the seed grow to the seedling of Y. longistaminea subjected to a autumn→winter→spring temperature process in nature conditions. Warm and cold stratification can alleviate radicle and epicotyl dormancy, respectively. The duration of cold stratification also significantly affects the epicotyl dormancy release of Y. longistaminea. The researches on the seeds breaking methods: warm(28°C/20°C)→cold(5°C)→GA3(100mg·L−1)→warm(28°C/20°C).

scholarly journals Class I β-1,3-Glucanase and Chitinase Are Expressed in the Micropylar Endosperm of Tomato Seeds Prior to Radicle Emergence

2001 ◽  
Vol 126 (3) ◽  
pp. 1299-1313 ◽  
Author(s):  
Chun-Ta Wu ◽  
Gerhard Leubner-Metzger ◽  
Frederick Meins ◽  
Kent J. Bradford
Keyword(s):  
Class I ◽  
Tomato Seeds ◽  
Radicle Emergence ◽  
Micropylar Endosperm

scholarly journals Distinct expression patterns of β-1,3-glucanases and chitinases during the germination of Solanaceous seeds

2003 ◽  
Vol 13 (2) ◽  
pp. 139-153 ◽  
Author(s):  
Luciana Petruzzelli ◽  
Kerstin Müller ◽  
Katrin Hermann ◽  
Gerhard Leubner-Metzger
Keyword(s):  
Seed Germination ◽  
Petunia Hybrida ◽  
Expression Patterns ◽  
Seedling Development ◽  
Solanaceous Species ◽  
Physalis Peruviana ◽  
Evolutionarily Conserved ◽  
Radicle Emergence ◽  
Micropylar Endosperm ◽  
Species Specific

AbstractThe expression patterns of β-1,3-glucanases (βGlu) and chitinases (Chn) were investigated during the seed germination of members of the Cestroideae (three Nicotiana species, Petunia hybrida) and the Solanoideae (Capsicum annuum, Physalis peruviana) subgroups of Solanaceous species. Rupture of the micropylar testa (seed coat) and rupture of the micropylar endosperm, i.e. radicle emergence, were distinct and temporally separate events during the germination of Cestroideae-type seeds. βGlu accumulation in imbibed Cestroideae-type seeds, occurring after testa rupture but prior to endosperm rupture, was inhibited by abscisic acid (ABA) and promoted by gibberellins (GA) and light, in strict association with germination, and appeared to be caused by transcriptional regulation of the class I βGlu genes. The micropylar cap of Solanoideae-type seeds does not allow a distinction between testa and endosperm rupture, but βGlu accumulation occurred prior to radicle emergence of pepper and P. peruviana seeds. ABA inhibited endosperm rupture and βGlu accumulation in the micropylar cap of pepper seeds. In contrast to tomato, βGlu accumulation in pepper seeds was not only confined to the micropylar cap, was due to distinct, tissue-specific βGlu isoforms, and was not accompanied by Chn accumulation. In conclusion, ABA inhibition of germination and βGlu accumulation in the micropylar endosperm appears to be a widespread event during the seed germination of Solanaceous species. In contrast, accumulation of Chn and distinct βGlu isoforms in the embryo, prior to germination, appears to be a species-specific phenomenon within the Solanaceae. In addition, a post-germination co-induction of βGlu and Chn in the root of the emerged seedling was found in endospermic and non-endospermic species and could represent an evolutionarily conserved event during dicot seedling development.

scholarly journals Effects of cold stratification on the endogenous hormone, dormancy and germination of Cornus walteri Wanger seeds

2020 ◽  
Vol 49 (3) ◽  
pp. 507-514
Author(s):  
Li Donglin ◽  
Jin Yaquin ◽  
Yu Chengjing ◽  
Xue Yuan
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Environmental Factors ◽  
Seed Dormancy ◽  
Zeatin Riboside ◽  
Endogenous Hormone ◽  
Gas Content ◽  
Cold Stratification ◽  
Plant Life ◽  
Critical Phase

The most critical phase in plant life is the germination period, which is influenced by both intrinsic and environmental factors. Assessment of cold stratification on several endogenous hormone, IAA, abscisic acid (ABA), gibberellin GA1/3 (GA1/3), zeatin-riboside (ZRs) and isopen-tenyl adenine (iPAs), and germination of Cornus walteri Wanger. seeds was done. Relationship between endogenous hormone and seed germination and mechanism of seed dormancy of C. walteri were also analysed. The results showed that the significant fluctuatation of both IAA and iPAs content was fond during cold stratification period, while the variation of ZRs was little, that of both ABA and GAs content increased with old stratification days. Effects of cold stratification on both GR and GP were significant (p < 0.05), which play an important role in releaving of seed germination and improving seed germination. The GR and GP were significantly negatively correlated with the contents of ABA and GA1/3, and positively correlated with the following iPAs, ZRs/ABA, iPAs/ABA.

scholarly journals Effect of stratification and gibberellic acid on epicotyl dormancy release in seeds of Yunnanopilia longistaminea (Opiliaceae)

2016 ◽  
Author(s):  
Guan-song Yang ◽  
Liu Yang ◽  
Yue-hua Wang ◽  
Shi-kang Shen
Keyword(s):  
Seed Germination ◽  
Gibberellic Acid ◽  
Economic Value ◽  
Cold Stratification ◽  
Dormancy Release ◽  
Spring Temperature ◽  
Edible Plant ◽  
Seed Moisture Content ◽  
Radicle Emergence ◽  
Shoot Emergence

Yunnanopilia longistaminea is an endangered monotypic species belonging to Opiliaceae. This edible plant is an important germplasm source with a high economic value in China. The seed dormancy and germination of Opiliaceae species have been rarely investigated. This study examined the effects of scarification, soaking in gibberellic acid, and dehydration on the seed germination of Y. longistaminea. Results indicated that the seed germination of this species involves two stages: radicle emergence and epicotyls (shoot) emergence. During radicle emergence, the optimum temperatures were 28 °C and 28 °C/20 °C. Seed moisture content and viability decreased as dehydration occurred. Thus, the seeds may be recalcitrant. The optimum GA3 solution for the seeds undergoing shoot emergence was 100 mg·L−1. The percentages of shoot emergence in 7 and 14 days of stratification at 5 °C were slightly higher than those in other groups. This study is the first to describe epicotyl dormancy in Y. longistaminea seeds. From the seed grow to the seedling of Y. longistaminea subjected to a autumn→winter→spring temperature process in nature conditions. Warm and cold stratification can alleviate radicle and epicotyl dormancy, respectively. The duration of cold stratification also significantly affects the epicotyl dormancy release of Y. longistaminea. The researches on the seeds breaking methods: warm(28°C/20°C)→cold(5°C)→GA3(100mg·L−1)→warm(28°C/20°C).

scholarly journals Effect of Environmental Factors on the Germination and Emergence of Drunken Horse Grass (Achnatherum inebrians)

Weed Science ◽  
2020 ◽  
pp. 1-29
Author(s):  
Yonghuan Yue ◽  
Guili Jin ◽  
Weihua Lu ◽  
Ke Gong ◽  
Wanqiang Han ◽  
...  
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Abiotic Factors ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Germination Percentage ◽  
Western China ◽  
Burial Depth ◽  
Achnatherum Inebrians ◽  
Water Ph

Abstract Drunken horse grass [Achnatherum inebrians (Hance) Keng] is a perennial poisonous weed in western China. A comprehensive understanding of the ecological response of A. inebrians germination to environmental factors would facilitate the formulation of better management strategies for this weed. Experiments were conducted under laboratory conditions to assess the effects of various abiotic factors, including temperature, light, water, pH and burial depth, on the seed germination and seedling emergence of A. inebrians. The seeds germinated at constant temperatures of 15, 20, 25, 30, 35°C and in alternating-temperature regimes of 15/5, 20/10, 25/15, 30/20, 35/25, 40/30°C, and the seed germination percentages under constant and alternating temperatures ranged from 51% to 94% and 15% to 93%, respectively. Maximum germination occurred at a constant temperature of 25°C, and germination was prevented at 45/35°C. Light did not appear to affect seed germination. The germination percentage of seeds was more than 75% in the pH range of 5 to 10, with the highest germination percentage at pH 6. The seeds germinated at osmotic potentials of 0 MPa to -1.0 MPa, but decreasing osmotic potential inhibited germination, with no germination at -1.2MPa. After 21 d of low osmotic stress, the seeds that did not germinate after rehydration had not lost their vitality. The seedling emergence percentage was highest (90%) when seeds were buried at 1 cm but declined with increasing burial depth and no emergence at 9 cm. Deep tillage may be effective in limiting the seed germination and emergence of this species. The results of this study provide useful information on the conditions necessary for A. inebrians germination and provide a theoretical basis for science-based prediction, prevention and control of this species.

Alleviation of dormancy in annual ryegrass (Lolium rigidum) seeds by hydration and after-ripening

Weed Science ◽  
2004 ◽  
Vol 52 (6) ◽  
pp. 968-975 ◽  
Author(s):  
Robert S. Gallagher ◽  
Kathryn J. Steadman ◽  
Andrew D. Crawford
Keyword(s):  
Seed Germination ◽  
Relative Humidity ◽  
Germination Rate ◽  
Dormancy Release ◽  
Annual Ryegrass ◽  
Dormant Seed ◽  
Lolium Rigidum ◽  
Time Model ◽  
Treatment Regimens ◽  
Two Populations

The effect of hydration (priming) treatment on dormancy release in annual ryegrass seeds from two populations was investigated. Hydration duration, number, and timing with respect to after-ripening were compared in an experiment involving 15 treatment regimens for 12 wk. Seeds were hydrated at 100% relative humidity for 0, 2, or 10 d at Weeks 1, 6, or 12 of after-ripening. Dormancy status was assessed after each hydration treatment by measuring seed germination at 12-hourly alternating 25/15 C (light/dark) periods using seeds directly from the hydration treatment and seeds subjected to 4 d postpriming desiccation. Seeds exposed to one or more hydration events during the 12 wk were less dormant than seeds that remained dry throughout after-ripening. The longer hydration of 10 d promoted greater dormancy loss than either a 2-d hydration or no hydration. For the seed lot that was most dormant at the start of the experiment, two or three rather than one hydration event or a hydration event earlier rather than later during after-ripening promoted greater dormancy release. These effects were not significant for the less-dormant seed lot. For both seed lots, the effect of a single hydration for 2 d at Week 1 or 6 of after-ripening was not manifested until the test at Week 12 of the experiment, suggesting that the hydration events alter the rate of dormancy release during subsequent after-ripening. A hydrothermal priming time model, usually used for modeling the effect of priming on germination rate of nondormant seeds, was successfully applied to dormancy release resulting from the hydration treatments.

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