scholarly journals DÉFICIT HÍDRICO E A GERMINAÇÃO DE SEMENTES DE HÍBRIDOS DE MILHO

Nativa ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 240-246
Author(s):  
Ivanildo Guilherme Henrique ◽  
Rafael Orlandini Bosqueiro ◽  
Rafael Massaru Kotsubo ◽  
Silvia de Carvalho Campos Botelho

Considerando a importância da água no processo de germinação de sementes, as condições adversas de umidade afetam diretamente o processo germinativo. Para tanto, objetivou-se avaliar a influência do deficit hídrico na germinação e vigor de sementes de dois genótipos comerciais de milho, induzido por diferentes potenciais osmóticos. Utilizou-se delineamento experimental inteiramente casualizados (DIC), arranjado em esquema fatorial duplo 2x5, com quatro repetições, avaliando híbridos de milho (DKB255PRO3 e DKB390PRO2), submetidos a germinação sob condições de déficit hídrico, em cinco níveis de potencial osmótico (0, -0,6, -1,2, -1,8 e -2,4 MPa). Cada unidade experimental constituiu-se por um rolo de papel germitest contendo 50 sementes. Utilizou-se NaCl como agente osmótico indutor de deficiência hídrica as sementes. Avaliou-se a germinação, vigor de sementes e o desenvolvimento inicial das plântulas, em termos de comprimento e biomassa. O déficit hídrico, simulado com solução de cloreto de sódio, provoca redução no desempenho de sementes de híbridos de milho. Os genótipos de milho respondem diferentemente quanto a tolerância a condições de estresse provocado por indisponibilidade de água durante a germinação. O híbrido DKB390PRO2 apresenta germinação e crescimento de plântulas superior quando submetido a diferentes níveis de potencial osmótico de NaCl. Palavras-chave: viabilidade de sementes; restrição hídrica; Zea mays.   Effect of water deficit on the maize seed germination   ABSTRACT: Considering the importance of water in the seed germination process and knowing that conditions will not always be the most adequate to the germination process, the objective was to evaluate the influence of water deficit on germination and vigor in seeds of different commercial corn genotypes induced by different osmotic potentials. A completely randomized experimental design (D.I.C) was used, arranged in a 2x5 double factorial scheme, with four replications. Each experimental unit was constituted by a roll containing 50 seeds, made in germitest paper. Two maize seed hybrids (DKB255PRO3 and DKB390PRO2) were evaluated, submitted to germination under water deficit conditions, with levels 0; -0,6. -1,2; -1,8 and -2,4 MPa of osmotic potential. NaCl was used as osmotic agent inducing water deficiency in seeds. Germination, seed vigor and initial seedling development were evaluated in terms of length and biomass. The water deficit simulated with sodium chloride solution, causes a reduction in the performance of maize hybrids seeds. Corn genotypes respond differently to tolerance to stress conditions caused by unavailability of water during germination. The hybrid DKB390PRO2 presents superior germination and seedling growth when submitted to different levels of osmotic NaCl potential. Keywords: viability; water restriction; Zea mays.

2021 ◽  
Vol 43 ◽  
Author(s):  
Marcelo Coelho Sekita ◽  
Denise Cunha Fernandes dos Santos Dias ◽  
Daniel Teixeira Pinheiro ◽  
Aparecida Leonir da Silva ◽  
Antônio César Batista Matos ◽  
...  

Abstract: Nitric oxide (NO) can act in biochemical pathways of the germination process; however, there is little information about how it acts on the performance of pea seeds. The aim of this study was to evaluate the physiological and biochemical effects of NO on pea seed germination and vigor. Pea seeds cv. Itapuã 600 obtained from three seed lots with different levels of physiological quality were sown in a substrate moistened with water (control) or sodium nitroprusside (SNP) solution, a NO donor (50 μM), to assess germination, vigor, activity of antioxidant enzymes, reactive oxygen species, lipid peroxidation, and amylase activity. NO application does not alter pea seed germination, but it increases vigor. It is more effective in seeds with lower physiological potential. In addition, NO leads to reduction in oxidative stress, favors the translocation of reserves to the embryo, and has potential for use in the treatment of pea seeds to increase seed vigor.


2014 ◽  
Vol 36 (2) ◽  
pp. 178-185
Author(s):  
Mayara Wesley da Silva ◽  
Laise Guerra Barbosa ◽  
José Eduardo Santos Barboza da Silva ◽  
Keylan Silva Guirra ◽  
Diego Rangel da Silva Gama ◽  
...  

Zephyranthes sylvatica is a beautiful lily, endemic from the Brazilian Caatinga. Although it has a great ornamental potential, little is known about this species, especially regarding its seeds germination process. Aiming to characterize the germination of Z. sylvatica seeds, we studied its imbibition curve, optimum temperature and substrate for germination and seedling emergence, osmotic and salt stress tolerance, as well as the tolerance to frosting/ defrosting, which indicates long term cryostorage potential. The germination of Z. sylvatica presents a triphasic model of imbibition, in which the primary root protrusion occurs after 72 hours of imbibition. The ideal conditions for evaluating seed germination of Z. sylvatica is 25 ºC, in paper rolls. These seeds are highly tolerant to osmotic stress, but not to salt stress. Z. sylvatica seeds can be cryopreservated without loss of germination and seed vigor.


2018 ◽  
Vol 10 (9) ◽  
pp. 326
Author(s):  
Erivanessa C. Sousa ◽  
Janete R. Matias ◽  
Juliana P. Pamplona ◽  
Sara M. C. Carvalho ◽  
Helida C. Mesquita ◽  
...  

The beggartick (Bidens subalternans L.) is one of the main weeds present in agricultural crops, capable of adapting to different environmental conditions. The water stress caused by water deficiency can affect the germination of weed seeds and, consequently, their capacity to colonize the agroecosystem. Knowledge of germination under water stress can be important to obtain an adequate management of the species in the agricultural systems. The objective of this study was to determine the effects of water stress on the germination process and vigor of two batches of Bidens subalternans seeds under different osmotic agents. It was completely randomized experimental design was used, with four replicates of 25 seeds. The treatments were arranged in factorial 6 × 2, with the first factor corresponding six levels of osmotic potentials (0.0, -0.2, -0.4, -0.6, -0.8 and -1.0 MPa) and the second the batches (Pernambuco and Ceará). For the simulation of the water stress, the test of germination was installed in substrate paper blotting, moistened with solutions of polyethylene glycol (PEG 6000) and mannitol. The analyzed variables were germination, germination speed index, length and seedling dry mass. Water stress reduced germination, seed vigor and growth of seedlings in all batches of B. subalternans. Seeds of B. subalternans presented greater tolerance to stress induced by mannitol than to PEG-6000 in terms of germination and germination speed index. Regardless of the osmotic agent used for stress induction, B. subalternans seeds did not tolerate water stress higher than -0.4 MPa.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Heqin Li ◽  
Haiwang Yue ◽  
Junliang Xie ◽  
Junzhou Bu ◽  
Li Li ◽  
...  

AbstractAbiotic stresses, including cold and drought, negatively affect maize (Zea mays L.) seed field emergence and later yield and quality. In order to reveal the molecular mechanism of maize seed resistance to abiotic stress at seed germination, the global transcriptome of high- vigour variety Zhongdi175 exposed to cold- and drought- stress was analyzed by RNA-seq. In the comparison between the control and different stressed sample, 12,299 differentially expressed genes (DEGs) were detected, of which 9605 and 7837 DEGs were identified under cold- and drought- stress, respectively. Functional annotation analysis suggested that stress response mediated by the pathways involving ribosome, phenylpropanoid biosynthesis and biosynthesis of secondary metabolites, among others. Of the obtained DEGs (12,299), 5,143 genes are common to cold- and drought- stress, at least 2248 TFs in 56 TF families were identified that are involved in cold and/or drought treatments during seed germination, including bHLH, NAC, MYB and WRKY families, which suggested that common mechanisms may be originated during maize seed germination in response to different abiotic stresses. This study will provide a better understanding of the molecular mechanism of response to abiotic stress during maize seed germination, and could be useful for cultivar improvement and breeding of high vigour maize cultivars.


Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 780
Author(s):  
López-Coria ◽  
Sánchez-Sánchez ◽  
Martínez-Marcelo ◽  
Aguilera-Alvarado ◽  
Flores-Barrera ◽  
...  

In maize seed germination, the endosperm and the scutellum nourish the embryo axis. Here, we examined the mRNA relative amount of the SWEET protein family, which could be involved in sugar transport during germination since high [14-C]-glucose and mainly [14-C]-sucrose diffusional uptake were found in embryo tissues. We identified high levels of transcripts for SWEETs in the three phases of the germination process: ZmSWEET4c, ZmSWEET6b, ZmSWEET11, ZmSWEET13a, ZmSWEET13b, ZmSWEET14b and ZmSWEET15a, except at 0 h of imbibition where the abundance of each ZmSWEET was low. Despite the major sucrose (Suc) biosynthesis capacity of the scutellum and the high level of transcripts of the Suc symporter SUT1, Suc was not found to be accumulated; furthermore, in the embryo axis, Suc did not decrease but hexoses increased, suggesting an efficient Suc efflux from the scutellum to nourish the embryo axis. The influx of Glc into the scutellum could be mediated by SWEET4c to take up the large amount of transported sugars due to the late hydrolysis of starch. In addition, sugars regulated the mRNA amount of SWEETs at the embryo axis. These results suggest an important role for SWEETs in transporting Suc and hexoses between the scutellum and the embryo axis, and differences in SWEET transcripts between both tissues might occur because of the different sugar requirements and metabolism.


2012 ◽  
Vol 30 (2) ◽  
pp. 312-316 ◽  
Author(s):  
Rogério G Pêgo ◽  
José Antônio S Grossi ◽  
José Geraldo Barbosa

The soaking curve and the effect of temperature on the germination of daisy seeds (Chrysanthemum leucanthemum) were characterized in this study. To determine the soaking curve, four samples of 0.5 g of seeds were soaked in germitest paper moistened with distilled water and maintained in germinator at 25ºC. The seeds were weighed in periods of 0, 3, 6, 9, 12, 24, 36, 48, 60, 72, 84 and 96 hours using a precision digital balance of 0.0001 g. A triphasic pattern germination curve was adjusted, allowing the determination of the beginning and duration of the phase II of the germination process. The germination test was carried out with four replications of 50 seeds disposed in "Gerbox" boxes and placed in germinators at the temperatures of 20, 25, 30 or 20-30ºC. A completely randomized experimental design was used with four replications of 50 seeds. The data were submitted to the analysis of variance and the averages were compared by the Tukey test, at 5% of probability. For analysis of accumulated seed germination, regressions were adjusted based on period of experiment. The seeds presented a triphasic pattern of germination and the phases I and II lasted 12 and 48 hours, respectively. The best temperature for the germination of the seeds is 25ºC. The temperature of 30ºC promoted the thermoinhibition of germination and increased the dead and dormant seeds and abnormal seedlings.


Agrologia ◽  
2018 ◽  
Vol 4 (2) ◽  
Author(s):  
Stela Wusono ◽  
John M Matinahoru ◽  
CMA Watimena

Swietenia mahagoni is a timber forestry plants have allelopathy toxic, can interfere with the growth of surrounding plants. This study aimed to determine the effects of extracts from various parts of Swietenia mahagoni on seed germination of green beans and corn. This research was conducted at the Laboratory of Silviculture, an extract from a litter, fresh leaves, bark and roots of the Swietenia mahagoni plant and given to the seed germination green beans and corn. The results showed that the extract of fresh leaves and roots Swietenia mahagoni inhibit seed germination green beans and corn, while the provision of litter no effect. Green bean seed has a higher durability of the maize seed to allelopathy of root Swietenia mahagoni.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 347-348
Author(s):  
Kelsey Schubach ◽  
Bruno I Cappellozza ◽  
Marcos Renato Burim ◽  
André Velasco ◽  
Fernando Sagrado ◽  
...  

Abstract Alternatives that alleviate stress-related responses and improve performance of the beef cattle herd are imperative and deserve further investigation. In previous trials, administration of the bovine appeasing substance (BAS) has improved performance of newly-weaned and feedlot received beef animals, as well as reduced the risk of dark, firm, and dry (DFD) cuts in carcass obtained from Bos indicus cattle. Therefore, this study was designed to evaluate the effects of BAS administration at castration on pre-conditioning performance of crossbred beef animals. On day 0, 390 crossbred Angus × Nellore animals were ranked by initial shrunk BW (255 ± 21.1 kg) and assigned to receive or not (CON) 5 mL/head of BAS (SecureCattle; Nutricorp, Araras, SP, Brazil) immediately before castration. From d 0 to 30, animals within treatments were maintained in 2 feedot pens with a minimum distance (300 m) to avoid contact between treatment groups and received a grass hay-based diet (70:30 roughage:concentrate ratio) ad libitum. On day 30, animals were individually weighed following 16 hours of feed and water restriction. Hence, a descriptive analysis was performed to evaluate pen dry matter intake (DMI) and feed efficiency (FE). Animal was considered the experimental unit and all data were analyzed using the PROC MIXED procedure of SAS (version 9.4; SAS Inst. Inc., Cary, NC). Bovine appeasing substance administration at castration improved ADG and BW change (P < 0.0001) compared with CON cohorts (0.983 vs. 1.155 kg/d and 29.5 vs. 34.6 kg for ADG and BW change, respectively). Total DMI was similar among treatments when reported as kg/d (6.70 vs. 6.75 kg) or % of BW (2.48 vs. 2.48%), whereas FE was dramatically improved in BAS-administered animals (146 vs. 172 g/kg for CON and BAS, respectively). In summary, BAS administration improved performance of crossbred beef animals for 30 days post-castration.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiaolong Huang ◽  
Tian Tian ◽  
Jingzhong Chen ◽  
Deng Wang ◽  
Bingli Tong ◽  
...  

Abstract Background Cinnamomum migao is an endangered evergreen woody plant species endemic to China. Its fruit is used as a traditional medicine by the Miao nationality of China and has a high commercial value. However, its seed germination rate is extremely low under natural and artificial conditions. As the foundation of plant propagation, seed germination involves a series of physiological, cellular, and molecular changes; however, the molecular events and systematic changes occurring during C. migao seed germination remain unclear. Results In this study, combined with the changes in physiological indexes and transcription levels, we revealed the regulation characteristics of cell structures, storage substances, and antioxidant capacity during seed germination. Electron microscopy analysis revealed that abundant smooth and full oil bodies were present in the cotyledons of the seeds. With seed germination, oil bodies and other substances gradually degraded to supply energy; this was consistent with the content of storage substances. In parallel to electron microscopy and physiological analyses, transcriptome analysis showed that 80–90 % of differentially expressed genes (DEGs) appeared after seed imbibition, reflecting important development and physiological changes. The unigenes involved in material metabolism (glycerolipid metabolism, fatty acid degradation, and starch and sucrose metabolism) and energy supply pathways (pentose phosphate pathway, glycolysis pathway, pyruvate metabolism, tricarboxylic acid cycle, and oxidative phosphorylation) were differentially expressed in the four germination stages. Among these DEGs, a small number of genes in the energy supply pathway at the initial stage of germination maintained high level of expression to maintain seed vigor and germination ability. Genes involved in lipid metabolism were firstly activated at a large scale in the LK (seed coat fissure) stage, and then genes involved in carbohydrates (CHO) metabolism were activated, which had their own species specificity. Conclusions Our study revealed the transcriptional levels of genes and the sequence of their corresponding metabolic pathways during seed germination. The changes in cell structure and physiological indexes also confirmed these events. Our findings provide a foundation for determining the molecular mechanisms underlying seed germination.


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