Seed-germination response of Leymus chinensis to cold stratification in a range of temperatures, light and low water potentials under salt and drought stresses

2017 ◽  
Vol 68 (2) ◽  
pp. 188 ◽  
Author(s):  
Jixiang Lin ◽  
Yujie Shi ◽  
Shuang Tao ◽  
Xingyang Yu ◽  
Dafu Yu ◽  
...  
Keyword(s):  
Drought Stress ◽  
Seed Germination ◽  
Drought Tolerance ◽  
Northeast China ◽  
Germination Percentage ◽  
Leymus Chinensis ◽  
Grass Species ◽  
Cold Stratification ◽  
Effective Measure ◽  
Salt And Drought Stresses

Leymus chinensis has important forage value and is considered a useful grass species for grassland restoration in Northeast China. However, little information exists concerning the germination responses of this species to interactions of cold stratification, light, temperature and low water potential caused by salinity and drought. Experiments were conducted in growth chambers, and the results showed that in all conditions of light, temperature and water stresses, the germination percentages of cold-stratified seeds were higher than of non-stratified seeds. Light had an inhibitory effect on germination percentage under both non-saline and salt stress conditions; darkness is beneficial for germination of this species. In addition, seeds germinated much better under alternating temperature regimes than under constant temperatures. Both salt and drought stresses decreased the germination percentage of Leymus chinensis, but the reductions under drought stress were much greater. Moreover, after being transferred to distilled water, most non-germinated seeds under drought stress germinated well, and the total percentage reached that of the non-saline condition level. Therefore, cold stratification is an effective measure to increase seed germination and salt or drought tolerance, especially in darkness. We conclude that Leymus chinensis has definite salt and drought tolerance during the germination stage and it is a promising species for the restoration of deteriorated grassland in Northeast China.

scholarly journals QTL Mapping for Seed Germination Response to Drought Stress in Brassica napus

2021 ◽  
Vol 11 ◽  
Author(s):  
Mahmoud Gad ◽  
Hongbo Chao ◽  
Huaixin Li ◽  
Weiguo Zhao ◽  
Guangyuan Lu ◽  
...  
Keyword(s):  
Drought Stress ◽  
Brassica Napus ◽  
Seed Germination ◽  
Drought Tolerance ◽  
Germination Percentage ◽  
Shoot Length ◽  
Stress Index ◽  
Phenotypic Analysis ◽  
Genetic Characteristics ◽  
Physical Maps

Drought stress is one of the most environmental abiotic stresses affecting seed germination and crop growth. In the present study, the genetic characteristics of seed germination under drought stress in a Brassica napus double haploid population were analyzed. Five germination-related indexes, including germination percentage (GP), root length (RL), shoot length (SL), fresh weight (FW), and root-to-shoot length ratio (R/S) under control and drought stress, were calculated, and the drought stress index (DSI), including DSI-GP, DSI-RL, DSI-SL, DSI-FW, and DSI-R/S, was determined using the quantitative trait loci (QTLs) analysis based on high-density genetic linkage map. The phenotypic analysis indicated that the R/S is an effective morphological trait in the determination of drought tolerance in the seedling stage. Thirty-nine identified QTLs were observed for these traits and then integrated into 36 consensus QTLs, in which 18 QTLs were found to affect the DSI of four traits (GP, RL, SL, and R/S). Based on the co-linearity between genetic and physical maps of B. napus, 256 candidate genes were detected, and 128 genes have single-nucleotidepolymorphisms/insertion–deletion (SNP/InDel) variations between two parents, some of which were associated with the drought stress tolerance (for example, BnaC03g32780D, BnaC03g37030D, and BnaC09g27300D). The present results laid insights into drought tolerance and its genetic bases in B. napus.

scholarly journals Transcriptional Regulation of Hydrogen Peroxide and Calcium for Signaling Transduction and Stress-defensive Genes Contributing to Improved Drought Tolerance in Creeping Bentgrass

2020 ◽  
Vol 145 (4) ◽  
pp. 236-246
Author(s):  
Zhou Li ◽  
Yan Peng ◽  
Bingru Huang
Keyword(s):  
Transcription Factors ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Creeping Bentgrass ◽  
Grass Species ◽  
Regulation Of Transcription ◽  
Signaling Transduction ◽  
Genes Expression ◽  
Protective Genes ◽  
Ca Signaling

Small molecules, including H2O2 and Ca, mediate stress signaling and drought tolerance in plants. The objective of this study was to determine whether improvement in drought tolerance by H2O2 and Ca were associated with the regulation of transcription factors and stress-protective genes in perennial grass species. Plants of creeping bentgrass (Agrostis stolonifera) were sprayed with water (control), H2O2 (9 mm), or CaCl2 (10 mm) and exposed to drought stress for 20 days in controlled-environment growth chambers. Foliar application of H2O2 or Ca led to significant improvement in drought tolerance of creeping bentgrass, as demonstrated by greater turf quality, leaf relative water content, chlorophyll content, photochemical efficiency, and cell membrane stability, as compared with the untreated control. The application of H2O2 and Ca resulted in significant up-regulation of genes in Ca signaling transduction pathways [Ca-dependent kinase 26 (CDPK26), mitogen-activated protein kinase 1 (MAPK1), and 14-3-3] and transcript factors (WRKY75 and MYB13). For genes encoding antioxidant enzymes, H2O2 mainly enhanced superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and dehydroascorbate reductase (DHAR) expression, while Ca primarily improved transcript levels of SOD, monodehydroascorbate reductase (MDHAR), and GR. In addition, heat shock protein 70 (HSP70), metallothionein 1 (MT1), and glutamine synthetase 2 (GS2) were also markedly up-regulated by H2O2 and Ca under drought stress. However, the transcript level of lipoxygenase 3 (LOX3) was significantly down-regulated by H2O2 and Ca under well-watered and drought conditions. These results imply that H2O2 and Ca commonly or differentially regulate genes expression in association with drought tolerance through activating Ca signaling pathway and regulating transcription factors and stress-protective genes expression, leading to the alleviation of lipid peroxidation, maintenance of correct protein folding and translocation, and enhancement of nitrogen metabolism under a prolonged period of drought stress in creeping bentgrass.

Phytohormone cross-talk and antioxidant gadgets tussles osmotic stress in indigenous rice landraces during seed germination

2020 ◽  
Author(s):  
R. Anupriya ◽  
Sugitha Thankappan ◽  
A. Senthil ◽  
D. Rajakumar ◽  
Geetha S ◽  
...  
Keyword(s):  
Drought Stress ◽  
Seed Germination ◽  
Drought Tolerance ◽  
Cross Talk ◽  
Tamil Nadu ◽  
Critical Role ◽  
Hydrolytic Enzyme ◽  
Rice Landraces ◽  
Drought Tolerant ◽  
Root And Shoot Length

Abstract Seed germination plays a critical role in determining rice productivity under drought stress. We evaluated 100 traditional rice landraces originated from different agro-ecological zones of Tamil Nadu along with drought- susceptible (IR 64) and drought- tolerant (IR 64 DRT) checks. Moisture stress was induced using PEG 6000 and screening done over a range of osmotic potentials (-) 10 bars, (-) 12.5 bars and (-)15 bars for a period of 5 d. Physio-morphological traits such as germination rate, survival per cent, root and shoot length, vigor index, RS ratio and relative water content (RWC) were assessed during early drought stress. We observed significant changes in the seed macromolecules, phytohormone levels (GA and IAA), osmolytes and antioxidant responses (catalase and superoxide dismutase) between drought stress and control treatments. Kuliyadichan registered significantly higher IAA and GA (44% and 35% respectively over drought tolerant check IR 64 DRT) at drought stress, whereas all the landraces showed an elevated catalase activity. In PC analysis, first three PCs captured 88.93% of the total variation; significant differences were detected among genotypes with respect to the studied parameters. Six traditional landraces such as Kuliyadichan, Rajalakshmi, Sabhagidhan, Nootripathu, Chandaikar and Mallikar were selected and their inherent drought tolerance was associated with metabolic responses viz., triggered hydrolytic enzyme activities, hormonal cross-talk, ROS signaling and catalase under drought stress compared to drought sensitive IR64. Hence, these genotypes can be used as potential donor candidates towards genetic improvement of drought tolerance in rice.

scholarly journals BrEXLB1, a Brassica rapa Expansin-Like B1 Gene Is Associated with Root Development, Drought Stress Response, and Seed Germination

Genes ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 404 ◽  
Author(s):  
Muthusamy Muthusamy ◽  
Joo Yeol Kim ◽  
Eun Kyung Yoon ◽  
Jin A. Kim ◽  
Soo In Lee
Keyword(s):  
Abiotic Stress ◽  
Drought Stress ◽  
Stress Response ◽  
Seed Germination ◽  
Drought Tolerance ◽  
Root Growth ◽  
Brassica Rapa ◽  
Root Development ◽  
Clubroot Disease ◽  
Qrt Pcr

Expansins are structural proteins prevalent in cell walls, participate in cell growth and stress responses by interacting with internal and external signals perceived by the genetic networks of plants. Herein, we investigated the Brassica rapa expansin-like B1 (BrEXLB1) interaction with phytohormones (IAA, ABA, Ethephon, CK, GA3, SA, and JA), genes (Bra001852, Bra001958, and Bra003006), biotic (Turnip mosaic Virus (TuMV), Pectobacterium carotovorum, clubroot disease), and abiotic stress (salt, oxidative, osmotic, and drought) conditions by either cDNA microarray or qRT-PCR assays. In addition, we also unraveled the potential role of BrEXLB1 in root growth, drought stress response, and seed germination in transgenic Arabidopsis and B. rapa lines. The qRT-PCR results displayed that BrEXLB1 expression was differentially influenced by hormones, and biotic and abiotic stress conditions; upregulated by IAA, ABA, SA, ethylene, drought, salt, osmotic, and oxidative conditions; and downregulated by clubroot disease, P. carotovorum, and TuMV infections. Among the tissues, prominent expression was observed in roots indicating the possible role in root growth. The root phenotyping followed by confocal imaging of root tips in Arabidopsis lines showed that BrEXLB1 overexpression increases the size of the root elongation zone and induce primary root growth. Conversely, it reduced the seed germination rate. Further analyses with transgenic B. rapa lines overexpressing BrEXLB1 sense (OX) and antisense transcripts (OX-AS) confirmed that BrEXLB1 overexpression is positively associated with drought tolerance and photosynthesis during vegetative growth phases of B. rapa plants. Moreover, the altered expression of BrEXLB1 in transgenic lines differentially influenced the expression of predicted BrEXLB1 interacting genes like Bra001852 and Bra003006. Collectively, this study revealed that BrEXLB1 is associated with root development, drought tolerance, photosynthesis, and seed germination.

scholarly journals Seed Priming: A Feasible Strategy to Enhance Drought Tolerance in Crop Plants

2020 ◽  
Vol 21 (21) ◽  
pp. 8258 ◽  
Author(s):  
Vishvanathan Marthandan ◽  
Rathnavel Geetha ◽  
Karunanandham Kumutha ◽  
Vellaichamy Gandhimeyyan Renganathan ◽  
Adhimoolam Karthikeyan ◽  
...  
Keyword(s):  
Drought Stress ◽  
Seed Germination ◽  
Drought Tolerance ◽  
Defense Mechanism ◽  
Seed Priming ◽  
Crop Productivity ◽  
Crop Plants ◽  
Complex Nature ◽  
Efficient Manner ◽  
Farming Community

Drought is a serious threat to the farming community, biasing the crop productivity in arid and semi-arid regions of the world. Drought adversely affects seed germination, plant growth, and development via non-normal physiological processes. Plants generally acclimatize to drought stress through various tolerance mechanisms, but the changes in global climate and modern agricultural systems have further worsened the crop productivity. In order to increase the production and productivity, several strategies such as the breeding of tolerant varieties and exogenous application of growth regulators, osmoprotectants, and plant mineral nutrients are followed to mitigate the effects of drought stress. Nevertheless, the complex nature of drought stress makes these strategies ineffective in benefiting the farming community. Seed priming is an alternative, low-cost, and feasible technique, which can improve drought stress tolerance through enhanced and advanced seed germination. Primed seeds can retain the memory of previous stress and enable protection against oxidative stress through earlier activation of the cellular defense mechanism, reduced imbibition time, upsurge of germination promoters, and osmotic regulation. However, a better understanding of the metabolic events during the priming treatment is needed to use this technology in a more efficient way. Interestingly, the review highlights the morphological, physiological, biochemical, and molecular responses of seed priming for enhancing the drought tolerance in crop plants. Furthermore, the challenges and opportunities associated with various priming methods are also addressed side-by-side to enable the use of this simple and cost-efficient technique in a more efficient manner.

Evaluation of green gram genotypes for drought tolerance by PEG (polyethylene glycol) induced drought stress at seedling stage

2019 ◽  
Author(s):  
M. Jincya ◽  
V. Babu Rajendra Prasad ◽  
P. Jeyakumara ◽  
A. Senthila ◽  
N. Manivannan
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Moisture Stress ◽  
Germination Percentage ◽  
Seedling Stage ◽  
Green Gram ◽  
Stress Index ◽  
Seedling Mortality ◽  
Seed Vigour ◽  
Selection Of

Drought stress is one of the major constraints for pulse production which negatively affecting its growth and production. Screening and selection of desirable genotypes for drought tolerance is the first and foremost important step in pulse breeding program. In green gram standardization for moisture stress was done under laboratory conditions using various concentration of PEG 6000 and 50% seedling mortality was observed at 0.5 MPa of moisture stress. Using this level of moisture stress 108 green gram genotypes were screened for their drought tolerance at seedling level and the following parameters viz., germination percentage, promptness index, radicle length, root length stress index, germination stress index and seed vigour were recorded. Observations revealed that the following green gram genotypes COGG 1332, VGG 16069, VGG 17003, VGG 17004, VGG 17009, VGG 17019 and VGG 17045 were found highly tolerant to moisture stress at seedling stage.

Interactive Effects of Salt and Drought Stresses on Seed Germination of Ammopiptanthus mongolicus in Northwest China

2014 ◽  
Vol 614 ◽  
pp. 653-657 ◽  
Author(s):  
Xiao Xue Shen ◽  
Min Wei Chai ◽  
Rui Li Li ◽  
Guo Yu Qiu
Keyword(s):  
Drought Stress ◽  
Seed Germination ◽  
Constant Temperature ◽  
Germination Rate ◽  
Northwest China ◽  
Interactive Effects ◽  
Regression Coefficients ◽  
Ammopiptanthus Mongolicus ◽  
Salt And Drought Stresses

A study quantifying the role of the interactive effects of salt and drought stresses, generally co-occurred in deserts, on seed germination in Ammopiptanthus mongolicus was conducted in a constant temperature incubator. The experiment consisted of seven levels of salinity stress (0, 0.3, 0.6, 0.9, 1.2, 1.5 and 1.8% NaCl) as well as six drought stress levels (0, -0.2, -0.4, -0.8, -1.6 and-2.0 MPa PEG). Accordant to our expectations, the interactive effects of salinity and drought stresses were additive on seed germination percentages, germination rate, and germination energy; significant decreases were seen in all of them in response to increases in salt and/or drought stresses. Furthermore, regression coefficients of salinity (β1) were higher than drought (β2), indicating that salinity was the first factor, and drought was secondary for salt and drought mixed stresses.

scholarly journals Temperature Requirements for Seed Germination of Three Penstemon Species'

HortScience ◽  
1990 ◽  
Vol 25 (2) ◽  
pp. 191-193 ◽  
Author(s):  
Phil S. Allen ◽  
Susan E. Meyer
Keyword(s):  
Seed Germination ◽  
Incubation Temperature ◽  
Marked Decrease ◽  
Rocky Mountain ◽  
Germination Percentage ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Primary Dormancy ◽  
Temperature Requirements ◽  
Seed Propagation

To determine optimum germination temperatures and effective dormancy-breaking procedures, field-grown (1983-85) seeds of `Bandera' Rocky Mountain penstemon (Penstemon strictus Benth), `Cedar' Palmer penstemon (Penstemon palmeri Gray), and firecracker penstemon (Penstemon eatonii Gray) were subjected to various cold stratification and incubation temperature treatments. Increased germination following an 8-week stratification occurred in seed lots containing dormant seeds, but a 2-week stratification generally failed to break dormancy. Older (1983) seeds of `Bandera' and `Cedar' penstemon germinated to full viability without stratification. All species showed a marked decrease in germination percentage above 20C; 15C consistently produced maximum germination after 4 weeks. At 15C, mean times to 90% of total germination were 11, 22, and 29 days for `Bandera', `Cedar', and firecracker penstemon, respectively. Transfer of seeds failing to germinate at warm temperatures (25 and 30C) to 15C and applying 720 μm gibberellic acid (GA3) solution was effective in breaking primary dormancy of firecracker penstemon and secondary dormancy of `Bandera' penstemon. Our findings suggest that incubation below 20C, combined with 8 weeks of stratification or the use of after-ripened seed, may improve seed propagation efforts for these species.

Effects of partial drying on seed germination in the aquatic grasses Zizania palustris L. and Porteresia coarctata (Roxb.) Tateoka

1992 ◽  
Vol 2 (4) ◽  
pp. 199-205 ◽  
Author(s):  
C. D. Aldridge ◽  
R. J. Probert
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Growth Regulators ◽  
Germination Percentage ◽  
Hormonal Status ◽  
Cold Stratification ◽  
Porteresia Coarctata ◽  
Germination Response ◽  
Fold Reduction ◽  
Germination Behaviour

AbstractPartial drying of non-dormant seeds had little effect on germination behaviour compared with undried controls. In contrast, partial drying resulted in a marked increase in the germination response of freshly harvested (dormant) seeds of Z. palustris. Partial drying also resulted in a 100-fold reduction in the concentration of gibberellins (GA4+7) required for maximum germination. Although the concentration range of applied abscisic acid (ABA) that permitted germination was unaltered, partial drying increased the final germination percentage at all concentrations tested. The concentration of ABA above which germination was reduced in freshly harvested (dormant) seeds of Z. palustris was 3.16 × 10−7m compared with 10−4m in fresh (non-dormant) seeds of P. coarctata. Changes in the germination response of Z. palustris seeds to applied growth regulators, following partial drying or cold stratification might be explained by similar changes in hormonal status.

scholarly journals Enhancement of Seed Germination in Common Carpetgrass and Centipedegrass Seed

HortScience ◽  
2000 ◽  
Vol 35 (4) ◽  
pp. 769-770 ◽  
Author(s):  
Edward W. Bush ◽  
Paul Wilson ◽  
Dennis P. Shepard ◽  
Gloria McClure
Keyword(s):  
Seed Germination ◽  
Warm Season ◽  
Germination Percentage ◽  
Grass Species ◽  
Maximum Effect ◽  
Germination Temperature ◽  
Eremochloa Ophiuroides ◽  
Mean Time

Priming or presoaking seed of common carpetgrass (Axonopus affinis Chase) and centipedegrass [Eremochloa ophiuroides Munro. (Kunz)] increased germination percentage and decreased mean time of germination (MTG) at 20, 25, and 30 °C. The effect of presoaking and priming was dependent on grass species and temperature. The optimum seed germination temperature for both of these warm-season species was 30 °C. Maximum effect on common carpetgrass or centipedegrass seeds was achieved by priming in 2% KNO3; higher concentrations did not improve germination percentage or MTG, and 4% was in some cases detrimental. Germination was higher and MTG lower at 20 and 30 °C than at 15 °C. Presoaking common carpetgrass and centipedegrass seeds was the most efficient seed enhancement treatment for germination at 30 °C.

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