scholarly journals Release of Medicago truncatula Gaertn. and Pisum sativum subsp. elatius (M. Bieb.) Asch. et Graebn. Seed Dormancy Tested in Soil Conditions

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1026
Author(s):  
Juan Pablo Renzi ◽  
Jan Brus ◽  
Stergios Pirintsos ◽  
László Erdős ◽  
Martin Duchoslav ◽  
...  
Keyword(s):  
Pisum Sativum ◽  
Medicago Truncatula ◽  
Seed Dormancy ◽  
Environmental Conditions ◽  
Common Garden ◽  
Soil Conditions ◽  
Bet Hedging ◽  
Soil Burial ◽  
Barrel Medic ◽  
Experimental Laboratory

Medicago truncatula (barrel medic) and Pisum sativum subsp. elatius (wild pea) accessions originating from variable environmental conditions in the Mediterranean basin were used to study physical seed dormancy (PY) release. The effect of soil burial on PY release was tested on 112 accessions of medic and 46 accessions of pea over the period of 3 months in situ at three common gardens (Hungary, Spain and Greece) from 2017 through 2019. PY release after soil exhumation followed by experimental laboratory germination of remaining dormant seeds (wet, 25 °C, 21 days) were related to the environmental conditions of the common garden and macroclimatic variables of the site of origin of the accessions. Higher PY release was observed in buried seeds under humid rather than under dry and hot environments. Exposure of remaining dormant seeds to experimental laboratory conditions increased total PY release up to 70% and 80% in barrel medic and wild pea, respectively. Wild pea showed higher phenotypic plasticity on PY release than barrel medic, which had higher bet-hedging within-season. Wild pea showed lower bet-hedging among-season (PY < 10%) in relation to precipitation than barrel medic, which was more conservative (PY ≈ 20%). Observed variability suggests that these species have the capability to cope with ongoing climate change.

scholarly journals Plasticity of Medicago truncatula seed dormancy relates to large-scale environment variation

2019 ◽  
Author(s):  
Juan Pablo Renzi ◽  
Martin Duchoslav ◽  
Jan Brus ◽  
Iveta Hradilová ◽  
Vilém Pechanec ◽  
...  
Keyword(s):  
Candidate Genes ◽  
Association Analysis ◽  
Medicago Truncatula ◽  
Seed Dormancy ◽  
Genome Wide Association ◽  
Dormancy Release ◽  
Bet Hedging ◽  
Genome Wide Association Analysis ◽  
Genome Wide ◽  
Plastic Responses

AbstractSeed dormancy and timing of its release is important developmental transition determining the survival of individual as well as population and species. We used Medicago truncatula as model to study legume seed dormancy in ecological and genomics context. The effect of oscillating temperatures as one of the dormancy release factor was tested over the period of 88 days on the set of 178 accessions originating from variable environmental conditions of Mediterranean basin. Phenotypic plasticity of final dormancy was significantly correlated with increased aridity, suggesting that plastic responses to external stimuli provide seeds with strong bet-hedging capacity and the potential to cope with high levels of environmental heterogeneity. Genome-wide association analysis identified candidate genes associated with dormancy release related to secondary metabolites synthesis, hormone regulation and modification of the cell wall likely mediating seed coat permeability and ultimately imbibition and germination.HighlightMedicago seed dormancy was correlated with increased aridity of the environment, suggesting that plastic responses provide seeds with a bet-hedging capacity. Genome-wide association analysis identified candidate genes associated with release from dormancy.

scholarly journals Regulation of Seed Dormancy and Germination Mechanisms in a Changing Environment

2021 ◽  
Vol 22 (3) ◽  
pp. 1357
Author(s):  
Ewelina A. Klupczyńska ◽  
Tomasz A. Pawłowski
Keyword(s):  
Climate Change ◽  
Seed Germination ◽  
Seed Dormancy ◽  
Environmental Conditions ◽  
Global Climate ◽  
Plant Evolution ◽  
Suitable Habitat ◽  
Climate Change Scenarios ◽  
Adaptation Mechanism ◽  
Seed Dormancy And Germination

Environmental conditions are the basis of plant reproduction and are the critical factors controlling seed dormancy and germination. Global climate change is currently affecting environmental conditions and changing the reproduction of plants from seeds. Disturbances in germination will cause disturbances in the diversity of plant communities. Models developed for climate change scenarios show that some species will face a significant decrease in suitable habitat area. Dormancy is an adaptive mechanism that affects the probability of survival of a species. The ability of seeds of many plant species to survive until dormancy recedes and meet the requirements for germination is an adaptive strategy that can act as a buffer against the negative effects of environmental heterogeneity. The influence of temperature and humidity on seed dormancy status underlines the need to understand how changing environmental conditions will affect seed germination patterns. Knowledge of these processes is important for understanding plant evolution and adaptation to changes in the habitat. The network of genes controlling seed dormancy under the influence of environmental conditions is not fully characterized. Integrating research techniques from different disciplines of biology could aid understanding of the mechanisms of the processes controlling seed germination. Transcriptomics, proteomics, epigenetics, and other fields provide researchers with new opportunities to understand the many processes of plant life. This paper focuses on presenting the adaptation mechanism of seed dormancy and germination to the various environments, with emphasis on their prospective roles in adaptation to the changing climate.

scholarly journals Characterisation of Medicago truncatula CLE34 and CLE35 in nodulation control

2020 ◽  
Author(s):  
Celine Mens ◽  
April H. Hastwell ◽  
Huanan Su ◽  
Peter M. Gresshoff ◽  
Ulrike Mathesius ◽  
...  
Keyword(s):  
Pisum Sativum ◽  
Medicago Truncatula ◽  
Sequence Homology ◽  
Dependent Manner ◽  
Legume Species ◽  
Mature Peptide ◽  
Cle Peptides ◽  
Autoregulation Of Nodulation ◽  
Cle Peptide ◽  
Distinct Role

AbstractLegume plants form a symbiosis with N2-fixing soil rhizobia, resulting in new root organs called nodules that enable N2-fixation. Nodulation is a costly process that is tightly regulated by the host through Autoregulation of Nodulation (AON) and nitrate-dependent regulation of nodulation. Both pathways require legume-specific CLAVATA/ESR-related (CLE) peptides. Nitrogen-induced nodulation-suppressing CLE peptides have not previously been characterised in Medicago truncatula, with only rhizobia-induced MtCLE12 and MtCLE13 identified. Here, we report on novel peptides MtCLE34 and MtCLE35 in nodulation control pathways. The nodulation-suppressing CLE peptides of five legume species were classified into three clades based on sequence homology and phylogeny. This approached identified MtCLE34 and MtCLE35 and four new CLE peptide orthologues of Pisum sativum. Whereas MtCLE12 and MtCLE13 are induced by rhizobia, MtCLE34 and MtCLE35 respond to both rhizobia and nitrate. MtCLE34 was identified as a pseudogene lacking a functional CLE-domain. Overexpression of MtCLE12, MtCLE13 and MtCLE35 inhibits nodulation. Together, our findings indicate that MtCLE12 and MtCLE13 have a distinct role in AON, while MtCLE35 regulates nodule numbers in a rhizobia- and nitrate-dependent manner. MtCLE34 likely had a similar role to MtCLE35 but its function was lost due to a nonsense mutation resulting in the loss of the mature peptide.

Opener, packer wheel and packing force effects on crop emergence and yield of direct seeded wheat, canola and field peas

2003 ◽  
Vol 83 (1) ◽  
pp. 129-139 ◽  
Author(s):  
A. M. Johnston ◽  
G. P. Lafond ◽  
W. E. May ◽  
G. L. Hnatowich ◽  
G. E. Hultgreen
Keyword(s):  
Grain Yield ◽  
Environmental Conditions ◽  
Direct Seeding ◽  
Soil Conditions ◽  
High Soil Moisture ◽  
Pea Seedlings ◽  
Field Peas ◽  
Furrow Opener ◽  
Direct Seeded ◽  
Moisture Conditions

An understanding of the effects of different opener designs and on-row packing force would help producers in their selection of appropriate direct seeding implement options for their soil conditions. A field trial was conducted at three locations (Indian Head, Sylvania and Watrous) in Saskatchewan from 1997 to 1999 to evaluate the effect of opener-packer design (spoon-steel V packer; spoon-flat rubber packer; paired row-steel V packer; paired row-flat rubber packer; sweep-pneumatic tire) in combination with a range of on-row packing forces [0, 333, 549, 746, and 1000 Newton (N) per press wheel] on crop emergence and grain yield with direct seeding. The differences observed between opener-packer combinations in this study varied by less than 10% for grain yield, and were almost always associated with the opener design and not the packer type. Despite the variable results, there was a tendency for higher pea and wheat emergence with the sweep + tire compared with other opener types at those locations that tended to be drier in the spring. Also, grain yield tended to be greater for the sweep + tire in 1999 at Indian Head, when the heavy-textured soil at this site had high soil moisture conditions at seeding. The responses to packing force varied with different years and among the crops. Generally, 333 N per press wheel provided adequate emergence and grain yield across the environmental conditions encountered in this study, regardless of the opener-packer combination. In 1997, 5% more pea seedlings emerged with some amount of packing compared with no packing. Relative to the check, some packing resulted in wheat grain yield that was 13% greater at three of the location-by-year combinations, and wheat emergence that was 9% greater in 1998. However, with canola excessive packing force (i.e., the two highest vs. lower packing forces) resulted in 11 fewer seedlings m-2 in 1999. A packing pressure of 333 N per press wheel provided adequate emergence and grain yield across varied environmental conditions, with higher packing force only negatively influencing emergence in canola, and not yield. Key words: Furrow opener, packing force, emergence, direct seeding, zero till

A model of stomatal closure driven by nonlinearities in soil-plant hydraulics

2021 ◽  
Author(s):  
Fabian Wankmüller ◽  
Mohsen Zarebanadkouki ◽  
Andrea Carminati
Keyword(s):  
Hydraulic Conductivity ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Environmental Conditions ◽  
Plant Traits ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Optimization Models ◽  
Soil Conditions

&lt;p&gt;Predicting plant responses to drought is a long-standing research goal. Since stomata regulate gas-exchange between plants and the atmosphere, understanding their response to drought is fundamental. Current predictions of stomatal behavior during drought mainly rely on empirical models. These models may suit well to a specific set of plant traits and environmental growth conditions, but their predictive value is doubtful when atmospheric and soil conditions change. Stomatal optimization offers an alternative framework to predict stomatal regulation in response to drought for varying environmental conditions and plant traits. Models which apply this optimization principle posit that stomata maximize the carbon gain in relation to a penalty caused by water loss, such as xylem cavitation. Optimization models have the advantage of requiring a limited number of parameters and have been successfully used to predict stomatal response to drought for varying environmental conditions and species. However, a mechanism that enables stomata to optimally close in response to water limitations, and more precisely to a drop in the ability of the soil-plant continuum to sustain the transpiration demand, is not known. Here, we propose a model of stomatal regulation that is linked to abscisic acid (ABA) dynamics (production, degradation and transport) and that allows plants to avoid excessive drops in leaf water potential during soil drying and increasing vapor pressure deficit (VPD). The model assumes that: 1) stomatal conductance (g&lt;sub&gt;s&lt;/sub&gt;) decreases when ABA concentration close to the guard cells (C&lt;sub&gt;ABA&lt;/sub&gt;) increases; 2) C&lt;sub&gt;ABA&lt;/sub&gt; increases with decreasing leaf water potential (due to higher production); and 3) C&lt;sub&gt;ABA&lt;/sub&gt; decreases with increasing photosynthesis (e.g. due to faster degradation or transport to the phloem). Our model includes simulations of leaf water potential based on transpiration rate, soil water potential and variable hydraulic conductances of key elements (rhizosphere, root and xylem), and a function linking stomatal conductance to assimilation. It was tested for different soil properties and VPD. The model predicts that stomata close when the relation between assimilation and leaf water potential becomes nonlinear. In wet soil conditions and low VPD, when there is no water limitation, this nonlinearity is controlled by the relation between stomatal conductance and assimilation. In dry soil conditions, when the soil hydraulic conductivity limits the water supply, nonlinearity is controlled by the excessive drop of leaf water potential for increasing transpiration rates. The model predicts different relations between stomatal conductance and leaf water potential for varying soil properties and VPD. For instance, the closure of stomata is more abrupt in sandy soil, reflecting the steep decrease in hydraulic conductivity of sandy soils. In summary, our model results in an optimal behavior, in which stomatal closure avoids excessive (nonlinear) decrease in leaf water potential, similar to other stomatal optimization models. As based on ABA concentration which increases with decreasing leaf water potential but declines with assimilation, this model is a preliminary attempt to link optimization models to a physiological mechanism.&lt;/p&gt;

scholarly journals Designing Cropping Systems to Improve the Management of the Invasive Weed Phalaris minor Retz.

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 809
Author(s):  
Gaofeng Xu ◽  
Shicai Shen ◽  
Yun Zhang ◽  
David Roy Clements ◽  
Shaosong Yang ◽  
...  
Keyword(s):  
Leaf Area ◽  
Seed Dormancy ◽  
Faba Bean ◽  
Cropping Systems ◽  
Germination Rate ◽  
Soil Conditions ◽  
Total Biomass ◽  
Invasive Weed ◽  
Research Attention ◽  
Phalaris Minor

Because cropping systems can greatly affect the establishment and spread of alien species populations, the design of cropping systems to control invasive weeds is an important approach for invasive species management in agro-ecosystems to avoid excessive increases in other control measures such as herbicides. The annual weed Phalaris minor Retz. (P. minor) is one of the most troublesome invasive weed species of winter crops in Yunnan Province, China, but the development of cropping systems for ecological control of this weed have received limited research attention. Here, we studied seed dormancy, germination characteristics and reproductive responses of P. minor to various cropping systems to show how cropping systems could be better designed to control P. minor in China. Our research showed that cropping systems significantly affected seed dormancy in submerged paddy fields. Phalaris minor seed remained dormant and the germination rates (less than 10%) were significantly lower (p < 0.05) than in maize fields and dry, bare soil conditions. Wheat, faba bean and rapeseed crops had no significant influence (p < 0.05) on the seed germination rate of P. minor, but increasing soil depth significantly decreased (p < 0.05) the germination rate and germination index of this weed. Total biomass, spike biomass, spike number and seed number of P. minor were significantly reduced (p < 0.05) with increasing proportions of the three crops (wheat, faba bean and rapeseed), with rapeseed having the strongest inhibition effects among the three crops. The reproductive allocation and reproductive investment of P. minor were also significantly reduced (p < 0.05) in mixed culture with wheat and rapeseed. With increasing proportions of wheat or rapeseed, the specific leaf area of P. minor significantly increased (p < 0.05), but the reverse was true for leaf area and specific leaf weight. Moreover, the net photosynthetic rate, stomatal conductance and transpiration rate for P. minor also decreased significantly (p < 0.05) when grown with wheat or rapeseed. These results suggest that optimal cropping systems design could involve planting rapeseed in conjunction with deep plowing and planting rice (continuous submergence underwater) in summer. Such a system could reduce the field populations and seed bank of P. minor, thus providing a sustainable and environmentally friendly means of suppressing P. minor.

Inheritance of three marker characters in Medicago truncatula Gaertn. (M. tribuloides Desr.)

1965 ◽  
Vol 16 (1) ◽  
pp. 31 ◽  
Author(s):  
JP Simon
Keyword(s):  
Medicago Truncatula ◽  
Recessive Gene ◽  
Morphological Characters ◽  
Anthocyanin Pigmentation ◽  
Genetic Studies ◽  
Seed Certification ◽  
Pigmentation Pattern ◽  
Barrel Medic ◽  
Complete Penetrance ◽  
Dominant Genes

The inheritance has been studied of three morphological characters which could be used as markers in the "pure seed" certification of commercial varieties of barrel medic, M. truncatula Gaertn. The leaf anthocyanin pigmentation pattern, as found in accession No. 2829, and the clockwise form of pod coiling characterizing accession No. 3309, are determined by single dominant genes. The spineless character of the pod of accession No. 2822 is due to a recessive gene. The simple inheritance of these characters and the complete penetrance of the genes concerned indicate that the anthocyanin marker and the spineless pod could be used for certification. Since the clockwise-anticlockwise pattern of coiling occurs in both forms in commercial barrel medic varieties, it is likely to be useful only as a marker in genetic studies. Details are given of a satisfactory procedure developed for crossing medic varieties

Sulphur and phosphorus fertilizers increase the yield of barrel medic (Medicago truncatula) five-fold in native pasture on a traprock soil

1989 ◽  
Vol 29 (4) ◽  
pp. 527 ◽  
Author(s):  
NM Clarkson ◽  
IF Swann ◽  
NP Chaplain
Keyword(s):  
Medicago Truncatula ◽  
Elemental Sulfur ◽  
Nitrogen Concentration ◽  
Nutrient Concentrations ◽  
Phosphorus Concentration ◽  
First Year ◽  
Yield Increase ◽  
Barrel Medic ◽  
Yield And Quality ◽  
Native Pasture

A single application of sulfur and phosphorus in the first year produced a 5-fold yield increase in barrel medic (Medicago truncatula cv. Jemalong), every year for 3 years, on traprock country in southern inland Queensland. In the first year, the yield of medic increased from 400 (untreated) to 1300 kg/ha with sulfur alone (at 40 kg/ha), and to 2300 kg /ha with sulfur and phosphorus together (both at 40 kg/ha). In the second and third years, sulfur and phosphorus together increased yields from 300 to 1400 kg/ha, and from 800 to 4000 kg/ha, respectively. The experiment tested factorial combinations of sulfur and phosphorus, both at 0, 10 and 40 kg/ha, 3 sources of sulfur (gypsum, superphosphate fortified with elemental sulfur and called 'super and sulfur', and elemental sulfur) and agricultural limestone at 2500 kg/ha. Seed and fertiliser were broadcast into a native pasture at the start of the experiment. Elemental sulfur was inferior to gypsum and 'super and sulfur' in the first year, but equally effective thereafter. There was no response to lime. Fertilising with sulfur and phosphorus together increased the sulfur concentration in medic tops from 0.10 to 0.23%, the phosphorus concentration from 0.19 to 0.23%, and the nitrogen concentration from 2.12 to 2.82%. Nutrient concentrations in plant and soil were examined as an aid to diagnosing deficiencies at other sites. We concluded that adequately fertilising medic with sulfur and phosphorus can greatly improve pasture yield and quality, and allow higher stocking rates on traprock country.

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