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Cees M Karssen - One of the best experts on this subject based on the ideXlab platform.

  • effects of endogenous nitrate content of Sisymbrium officinale seeds on germination and dormancy
    Royal Botanical Society of the Netherlands. Meetings, 1994
    Co-Authors: Harro J Bouwmeester, Leni Derks, Jakob J Keizer, Cees M Karssen
    Abstract:

    The nitrate content of seeds of the annual Sisymbrium officinale was raised by weekly nitrate fertilizations of the seeding mother plants. Nitrate content and germination of the seeds produced were positively correlated. Seed lots with different endogenous nitrate contents were buried at 10 cm in sandy loam. At regular intervals seeds were exhumed and germination was tested. Both the initial differences in endogenous nitrate content and the differences of germination rapidly diminished during burial because nitrate rapidly leached from the seeds. The sensitivity of exhumed seeds to applied nitrate strongly varied during this 1-year study. Sensitivity to nitrate was low in December and had increased in January-February probably because of low winter temperatures

  • annual changes in dormancy and germination in seeds of Sisymbrium officinale l scop
    New Phytologist, 1993
    Co-Authors: Harro J Bouwmeester, Cees M Karssen
    Abstract:

    SUMMARY The effect of environmental conditions on changes in dormancy and germination of seeds of Sisymbrium officinale (L.) Scop, was studied. Seeds were buried in soil in the field or in incubators and at regular intervals, germination of exhumed seeds was tested over a range of conditions. Seeds that were buried in the field showed clear seasonal changes in dormancy. Fluctuations in soil moisture and nitrate content were not required for the changes in dormancy. Temperature seemed to be the only factor regulating these changes. Dormancy was relieved in periods of low temperatures and induced in periods of high temperatures. Fresh seeds and seeds buried for only a few months germinated best at elevated temperatures whereas seeds buried for a longer time germinated best at low-temperatures. Light, nitrate and desiccation stimulated germination of exhumed seeds. As a consequence, these treatments extended germination over a much longer period of the year. Germination of exhumed seeds in Petri dishes at field temperature was reasonably described by a model based on the dual role of temperature, in the regulation of both dormancy and subsequent germination.

Peter Boutsalis - One of the best experts on this subject based on the ideXlab platform.

  • reduced translocation in 2 4 d resistant oriental mustard populations Sisymbrium orientale l from australia
    Pest Management Science, 2018
    Co-Authors: Hue Thi Dang, Peter Boutsalis, Jenna Malone, Gurjeet Gill, Mahima Krishnan, Christopher Preston
    Abstract:

    BACKGROUND Two oriental mustard populations (P2 and P13) collected from Port Broughton, South Australia were identified as resistant to 2,4-D. The level of resistance, mechanism and the mode of inheritance for 2,4-D resistance in these populations were investigated. RESULTS Populations P2 and P13 were confirmed to be resistant to 2,4-D at the field rate (600 g a.e. ha-1 ). P2 and P13 were 81- and 67-fold more resistant than the susceptible populations (S1 and S2) at the dose required for 50% mortality (LD50 ), respectively. No predicted amino acid modification was detected in sequences of potential target-site genes (ABP, TIR1 and AFB5). Resistant populations had reduced 2,4-D translocation compared with the susceptible populations, with 77% of [14 C]2,4-D retained in the treated leaf versus 32% at 72 h after treatment. Resistance to 2,4-D is encoded on the nuclear genome and is dominant, as the response to 2,4-D of all F2 individuals were similar to the resistant biotypes. The segregation of F2 phenotypes fitted a 3: 1 (R: S) inheritance model. CONCLUSION Resistance to 2,4-D in oriental mustard is likely due to reduced translocation of 2,4-D out of the treated leaf. Inheritance of 2,4-D resistance is conferred by a single gene with a high level of dominance. © 2017 Society of Chemical Industry.

  • identification of a target site mutation conferring resistance to triazine herbicides in oriental mustard Sisymbrium orientale l from australia
    Weed Biology and Management, 2017
    Co-Authors: Hue Thi Dang, Peter Boutsalis, Jenna Malone, Gurjeet Gill, Christopher Preston
    Abstract:

    In southern Australia, oriental mustard (Sisymbrium orientale) has been controlled successfully by triazine herbicides for several decades. The screening of 40 populations that were collected from the southern grain belt of Australia during 2010 and 2013 for resistance to six different herbicides (glyphosate, diflufenican, imazamox, chlorsulfuron, atrazine and 2,4-dichlorophenoxyacetic acid) identified two oriental mustard populations as highly resistant to atrazine. Compared to the known oriental mustard-susceptible populations (S1 and S2), these two resistant populations (P17 and P18) from near Horsham, Victoria, Australia, were 311- and 315-fold resistant to atrazine, as determined by a comparison of the LD50 values. However, there was no resistance to diuron detected in these populations. Sequencing of the chloroplast psbA gene identified a missense mutation of serine 264 to glycine in both herbicide-resistant oriental mustard populations, which is known to confer high-level atrazine resistance in other species.

  • Resistance to hormone mimic herbicides and acetohydroxyacid synthase-inhibiting herbicides in Sisymbrium orientale.
    2008
    Co-Authors: M. K. M. Aman, Peter Boutsalis, C. Preston
    Abstract:

    Sisymbrium orientale L. ( Indian hedge mustard) is an important broadleaf weed of cereal cropping in South Australia. S. orientale is readily controlled by the sulfonylurea herbicides that inhibit acetolactate synthase (ALS). Extensive use of these herbicides has resulted in widespread resistance in this weed in South Australia. To control ALS herbicideresistant S. orientale, farmers have reverted to the hormone mimic herbicides 2,4-D and MCPA. In 2005, failure of 2,4-D to control S. orientale was reported in a wheat field near Port Broughton, South Australia. Dose response experiments were conducted with hormone-mimic herbicides, AHAS-inhibiting herbicides and the phytoene desaturase inhibiting herbicide diflufenican. In these dose response experiments the resistant population proved to be resistant to 2,4-D and MCPA. It was also resistant to the AHAS-inhibiting herbicides metsulfuron-methyl, chlorsulfuron, imazethapyr, metosulam and florasulam. The resistant population could be controlled by diflufenican. When compared to two susceptible populations, the resistant population was 20-fold resistant to 2,4-D and MCPA. The resistant population was more than 500-fold resistant to chlorsulfuron, more than 400-fold resistant to metosulam, 32-fold resistant to metsulfuron-methyl, 23-fold resistant to florasulam and 4-fold resistant to imazethapyr. The 2,4-D-resistant and susceptible plants were crossed by hand. The seed produced on the susceptible Resistance to hormone mimic herbicides and acetohydroxyacid synthase-inhibiting herbicides in Sisymbrium orientale

  • molecular basis of resistance to acetolactate synthase inhibiting herbicides in Sisymbrium orientale and brassica tournefortii
    Pesticide Science, 1999
    Co-Authors: Peter Boutsalis, Jill Karotam, Stephen B Powles
    Abstract:

    Three Australian Sisymbrium orientale and one Brassica tournefortii biotypes are resistant to acetolactate synthase (ALS)-inhibiting herbicides due to their possession of an ALS enzyme with decreased sensitivity to these herbicides. Enzyme kinetic studies revealed no interbiotypic differences within species in K m (pyruvate) (the substrate concentration at which the reaction rate is half maximal) but a greater V max (the rate when the enzyme is fully saturated with substrate) for two of the resistant S orientale biotypes over susceptible levels. F 1 hybrids from reciprocal crosses between resistant and susceptible biotypes of S orientale showed an intermediate response to chlorsulfuron compared to the parental plants. ALS herbicide resistance in S orientale segregated in a 3:1 (resistant:susceptible) ratio in F 2 plants with a single rate of chlorsulfuron, indicating that resistance is inherited as a single, incompletely dominant nuclear gene. Two regions of the ALS structural gene known to vary in ALS-resistant biotypes were amplified and sequenced. Resistant S orientale biotypes NS01 and SS03 contained a single nucleotide substitution in Domain B, predicting a Trp (in susceptible) to Leu (in resistant) amino acid change. Two adjacent nucleotide substitutions (CCT to ATT) predicting a Pro (in susceptible) to Ile (in resistant) change in the primary amino acid sequence were identified in Domain A of resistant S orientale biotype SS01. Likewise, a single nucleotide substitution at the same site in the resistant B tournefortii biotype predicts a Pro (in susceptible) to Ala (in resistant) substitution. No other interbiotypic nucleotide differences predicted amino acid changes in the sequenced regions, suggesting that the amino acid substitutions reported above are responsible for resistance to ALS-inhibiting herbicides in the respective biotypes.

  • seedbank characteristics of herbicide resistant and susceptible Sisymbrium orientale
    Weed Research, 1998
    Co-Authors: Peter Boutsalis, Stephen B Powles
    Abstract:

    Germinability and emergence of Sisymbrium orientale Torn. seed susceptible and resistant to acetolactate synthase (ALS)-inhibiting herbicides was investigated. Freshly harvested seed from a field containing confirmed ALS-inhibiting herbicide-resistant (ALS resistant) plants and susceptible seed from a nearby field was found to exhibit strong innate dormancy initially. However, germinability of seed from both resistant and susceptible biotypes increased to 50% after 1 month, indicating that innate dormancy had been partly relieved. No significant differences in behaviour of resistant vs. susceptible biotypes were recorded over 3 years. Field experiments conducted over a 4-year experimental period, to determine seedbank longevity in the absence of fresh seed input to the seedbank, revealed S. orientale to have a short seedbank life. Cultivation stimulated seedling emergence compared with no-tillage seedling emergence. These findings establish that persistence of S. orientale in the seedbank is short if fresh seed production is prevented. This knowledge can be used to manage populations of S. orientale, especially in cases such as this where the population is herbicide-resistant.

Syed Nisar Hussain Shah - One of the best experts on this subject based on the ideXlab platform.

Barbara Neuffer - One of the best experts on this subject based on the ideXlab platform.

  • a story from the miocene clock dated phylogeny of Sisymbrium l sisymbrieae brassicaceae
    Ecology and Evolution, 2021
    Co-Authors: Anže žerdoner Calasan, Dmitry A German, Herbert Hurka, Barbara Neuffer
    Abstract:

    Morphological variability and imprecise generic boundaries have hindered systematic, taxonomical, and nomenclatural studies of Sisymbrium L. (Brassicaceae, Sisymbrieae DC.). The members of this almost exclusively Old-World genus grow mostly on highly porous substrates across open steppe, semidesert, or ruderal habitats in the temperate zone of the Northern Hemisphere and African subtropics. The present study placed the biological history of Sisymbrium L. into time and space and rendered the tribus Sisymbrieae as monotypic. Five nuclear-encoded and three chloroplast-encoded loci of approximately 85% of all currently accepted species were investigated. Several accessions per species covering their whole distribution range allowed for a more representative assessment of intraspecific genetic diversity. In the light of fossil absence, the impact of different secondary calibration methods and taxon sets on time spans was tested, and we showed that such a combinatorial nested dating approach is beneficial. Multigene phylogeny accompanied with a time divergence estimation analysis placed the onset and development of this tribus into the western Irano-Turanian floristic region during the Miocene. Continuous increase in continentality and decrease in temperatures promoted the diversity of the Sisymbrieae, which invaded the open grasslands habitats in Eurasia, Mediterranean, and South Africa throughout the Pliocene and Pleistocene. Our results support the assumption of the Irano-Turanian region as a biodiversity reservoir for adjacent regions.

Hanaa Fahmy S Shehata - One of the best experts on this subject based on the ideXlab platform.

  • ecology and nutritive status of Sisymbrium irio l in the nile delta egypt
    THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY, 2014
    Co-Authors: Hanaa Fahmy S Shehata
    Abstract:

    The present study was conducted to evaluate the ecology and nutritive potential of the wild herbal weed Sisymbrium irio in the Nile Delta region. Vegetation and soil were sampled in 50 stands distributed in different habitats in the Nile Delta region of Egypt where Sisymbrium irio was recorded. The present study was investigated in cultivated lands, road-sides, wastelands, orchards and canal banks in five Governorates of the Nile Delta: El-Sharkia, El-Gharbia, El-Behira, Kafr El-Sheikh and El-Dakhlia. The total number of the recorded plant species was 104, belonging to 88 genera and related to 31 families. Floristic analysis revealed that the recorded species were classified into three major functional groups according to their duration (life-span) as follows: 72 annuals, 3 biennials and 29 perennials. Therophytes exhibited the maximum number of species (72.13%). Seven vegetation groups (VG) were identified by the application of TWINSPAN and DECORANA as classification and ordination techniques, respectively. Each of these groups inhabited one or more distinct type of habitats. S. irio was recognized as dominant species for most of these groups and as an important species in group E certain species may show a local dominance/co-dominance, or may be distinctly the most important in a group of stands. The correlation between vegetation and soil characteristics is indicated on the ordination diagram produced by the Canonical Correspondence Analysis (CCA). Sand, silt, clay, pH, calcium carbonate, organic carbon, and water- holding capacity were the most significant soil factors controlling the abundance and distribution of the vegetation groups. The community of S. irio (dominant species in Groups B, F, and G) was affected by, calcium carbonate, water holding- capacity, Mg, Ca, and K. Evaluation of the nutritive status of S. irio shoots showed that sodium, potassium, calcium, magnesium, iron, zinc, and phosphorous were detected in adequate amounts, while copper, manganese, and nickel were below the maintenance level. The present study evaluated the nutritive status of S. irio as good forage.