Wild radish crept under the radar Prostko, Eric
Western Farm Press,
08/2021
Magazine Article, Journal Article, Trade Publication Article
Not exactly sure what happened here but a quote from the popular 1993 movie Jurassic Park sums it up nicely “Life finds a way!” Here are 10 wild radish facts that might help you better understand ...this weed: Wild radish emergence is significantly reduced when seeds are buried at depths greater than 3.2”. ...deep tillage would be a very beneficial component of control programs. Peanut weed control (23 DAP) with preemergence applications of Prowl or Sonalan + Valor + Strongarm in 2021 (lots of Palmer amaranth, wild radish, and annual grasses in the NTC plot).
Arabidopsis thaliana COMATOSE (CTS) encodes an ABC transporter involved in peroxisomal import of substrates for β-oxidation. Various cts alleles and mutants disrupted in steps of peroxisomal ...β-oxidation have previously been reported to exhibit a severe block on seed germination. Oxylipin analysis on cts, acyl CoA oxidase1 acyl CoA oxidase2 (acx1 acx2), and keto acyl thiolase2 dry seeds revealed that they contain elevated levels of 12-oxo-phytodienoic acid (OPDA), jasmonic acid (JA), and JA-Ile. Oxylipin and transcriptomic analysis showed that accumulation of these oxylipins occurs during late seed maturation in cts. Analysis of double mutants generated by crossing cts with mutants in the JA biosynthesis pathway indicate that OPDA, rather than JA or JA-Ile, contributes to the block on germination in cts seeds. We found that OPDA was more effective at inhibiting wild-type germination than was JA and that this effect was independent of CORONATINE INSENSITIVE1 but was synergistic with abscisic acid (ABA). Consistent with this, OPDA treatment increased ABA INSENSITIVE5 protein abundance in a manner that parallels the inhibitory effect of OPDA and OPDA+ABA on seed germination. These results demonstrate that OPDA acts along with ABA to regulate seed germination in ARABIDOPSIS:
Plastic pollution has become a global concern for ecosystem health and biodiversity conservation. Concentrations of plastics are manifold higher in the terrestrial system than the aquatic one. ...Micro/nanoplastics (M/NP) have the ability to alter soil enzymatic system, soil properties and also affect soil borne microorganisms and earthworms. Despite, the knowhow regarding modulatory effects of plastics are acquired from the study on aquatic system and reports on their phytotoxic potentials are limited. The presence of cell wall that could restrict M/NP invasion into plant roots might be the putative cause of this limitation. M/NP inhibit plant growth, seed germination and gene expression; and they also induce cytogenotoxicity by aggravating reactive oxygen species generation. Dynamic behavior of cell wall; the pores formed either by cell wall degrading enzymes or by plant–pathogen interactions or by mechanical injury might facilitate the entry of into roots M/NP. This review also provides a possible mechanism of large sized microplastics‐induced phytotoxicity especially for those that cannot pass through cell wall pores. As M/NP affect soil microbial community and soil parameters, it is hypothesized that they could have the potential to affect N2 fixation and research should be conducted in this direction. Reports on M/NP‐induced toxicity mainly focused only on one polymer type (polystyrene) in spite of the toxicological relevancies of other polymer types like polyethylene, polypropylene etc. So, the assessment of phytotoxic potential of M/NP should be done using other plastic polymers in real environment as they are known to intract with other environmental stressors as well as can alter the the soil–microbe–plant interaction.
Increased production of plastics, its fragmentation into micro/nano/sub‐nano ranged particles, biotic and abiotic interaction, bioaccumulation and the release of toxic substances make plastic pollution an emerging global threat for ecosystem and public health. A paucity of knowledge about how plastics interact with plant system and affect the soil–microbe–plant interaction could underestimate their actual ecotoxicological potential. As the cell wall may be a limiting factor for the assessment of phytotoxicity, in this review, we discussed some plausible routes plastics may follow to invade the plant and also raised some outstanding questions which are need to be focussed immediately.
Non-thermal plasma-activated water (PAW) is used in agriculture to decontaminate the seed/grains surface, with possible positive effects on physiological processes. In the present study, PAW was ...generated in ambient air at atmospheric pressure in eight variants with pH and different doses of reactive species (Hsub.2Osub.2, NOsub.3 sup.−). We explored the indirect effect of PAW on wheat grains while focusing on genetic material by cytogenetic monitoring. All PAW variants caused clastogenic and aneugenic events of the genetic material, with different intensities, in a dose-dependent manner of reactive species in plasma composition. PAW with the highest doses of Hsub.2Osub.2 (13-22 mg/L) and NOsub.3 sup.− (49-68 mg/L) at pH 3.8-4.1 decreased the mitotic index the most and induced the most frequent genetic abnormalities, out of which chromosomal bridges and micronuclei were dominant. In correlation with this damage at the nucleus level, the germination rate and root and shoot length of wheat sprouts decreased significantly only in the variants with the highest doses of reactive species. PAW with the lowest doses of Hsub.2Osub.2 (1-5 mg/L) and NOsub.3 sup.− (8-15 mg/L) at pH 5.5-5.1 induced a much lower cytogenotoxic potential, maintained a germination rate comparable to the control and even significantly stimulated root and shoot length growth. Thus, the effects of PAW depend highly on the dose of reactive species and on pH.
Mature seeds of many crop species contain substantial amounts of soluble carbohydrates, including raffinose family oligosaccharides (RFOs) and cyclitol galactosides (Gal-C). These substances are ...hydrolysed by α-D-galactosidase (EC 3.2.1.22) during the early stages of germination, providing metabolic energy for the germination process. A decrease or inhibition of α-D-galactosidase activity can significantly reduce the germination rate. This study aimed to investigate changes in α-D-galactosidase activity during the long-term storage of Vicia hirsuta seeds and evaluate the association between the loss of enzyme activity and the decline in seed vigour and viability. V. hirsuta seeds were stored at 22 °C and 35% relative humidity for up to 25 years, and α-D-galactosidase activity and seed vigour changes were monitored at different time points. Storage of V. hirsuta seeds resulted in a loss of viability and vigour, accompanied by a decrease in α-D-galactosidase activity. The enzyme activity showed a significant correlation with seed germinability and vigour. Monitoring α-D-galactosidase activity in seeds subjected to long-term storage could be a simple and rapid method for determining the decline in vigour in seeds that utilize soluble galactosides as their storage materials.
The effect of zinc on seed germination in two species of the
genus (
J.F. Gmelin and
L.) was investigated. Zinc was used as sulphate in three different concentrations: 100 mg∕ l; 200 mg ∕ l și 300 mg ...∕ l; the treatment was applied to the seeds before germination, the exposure time being short (4 hours and 8 hours). Seed germination was monitored daily for a period of 14 days. The effect of treatment on seed germination in the test species was assessed by calculating four germination indicators: final germination percentage (FGP), germination index (GI), mean germination time (MGT) and coefficient of rate germination (CRG). The results show the following: the seeds of
germinate faster than those of
; statistically insignificant changes in the indicators associated with germination, except for GI in
for the 8 hours exposure time; reduction of germination percentage (in both species) and increase in germination time (more evident in
) with increasing exposure time. The test species showed tolerance throughout the germination process to the zinc concentrations used.
Paeonia ostii is an important woody oil crop mainly cross-pollinated. However, the low yield has become an important factor restricting the industrial development of P. ostii. Cross-pollination has ...become one of the important measures to increase the seed yield. Therefore, conservation of pollen with high vitality is crucial to ensure successful pollination of P. ostii. In this study, we found an effective methodological system to assess the viability, ability to germinate, and optimal storage conditions of P. ostii pollen grains. The optimal medium in vitro was 50 g/L sucrose, 100 mg/L boric acid, 50 g/L PEG6000, 100 mg/L potassium nitrate, 300 mg/L calcium nitrate, and 200 mg/L magnesium sulfate at pH 5.4. Optimal germination condition in vitro was achieved at 25 °C for 120 min, allowing easy observation of the germination percentage and length of the pollen tubes. In addition, the viability of pollen grains was assessed by comparing nine staining methods. Among them, MTT, TTC, benzidine-Hsub.2Osub.2, and FDA were effective to distinguish between viable and non-viable pollen, and the results of the FDA staining method were similar to the pollen germination percentage in vitro. After evaluation of pollen storage, thawing and rehydration experiments showed that thawing at 4 °C for 30 min and rehydration at 25 °C for 30 min increased the germination percentage of pollen grains stored at low temperatures. The low-temperature storage experiments showed that 4 °C was suitable for short-term storage of P. ostii pollen grains, while −80 °C was suitable for long-term storage. This is the first report on the in vitro germination, viability tests, and storage of P. ostii pollen grains, which will provide useful information for P. ostii germplasm conservation and artificial pollination.
Phytohormones have essential roles in coordinately regulating a large array of developmental processes. Studies have revealed that brassinosteroids (BRs) and abscisic acid (ABA) interact to regulate ...hundreds of expression in genes, governing many biological processes. However, whether their interaction is through modification or intersection of their primary signaling cascades, or by independent or parallel pathways remains a big mystery. Using biochemical and molecular markers of BR signaling and ABA biosynthetic mutants, we demonstrated that exogenous ABA rapidly inhibits BR signaling outputs as indicated by the phosphorylation status of BES1 and BR-responsive gene expression. Experiments using a bri1 null-allele, bri1-116, and analysis of subcellular localization of BKI1-YFP further revealed that the BR receptor complex is not required for ABA to act on BR signaling outputs. However, when the BR downstream signaling component BIN2 is inhibited by LiCl, ABA failed to inhibit BR signaling outputs. Also, using a set of ABA insensitive mutants, we found that regulation of ABA on the BR primary signaling pathway depends on the ABA early signaling components, ABI1 and ABI2. We propose that the signaling cascades of ABA and BR primarily cross-talk after BR perception, but before their transcriptional activation. This model provides a reasonable explanation for why a large proportion of BR-responsive genes are also regulated by ABA, and provides an insight into the molecular mechanisms by which BRs could interact with ABA.
Thorough knowledge of the germination behavior of weed species could aid in the development of effective weed control practices, especially when glyphosate resistance is involved. A study was ...conducted using two glyphosate-resistant (GR) (SGW2 and CP2) and two glyphosate-susceptible (GS) (Ch and SGM2) populations of Chloris virgata, an emerging and troublesome weed species of Australian farming systems, to evaluate their germination response to different alternating temperature (15/5, 25/15 and 35/25°C with 12 h/12 h light/dark photoperiod) and moisture stress regimes (0, -0.1, -0.2, -0.4, -0.8 and -1.6 MPa). These temperature regimes represent temperatures occurring throughout the year in the eastern grain region of Australia. Seeds germinated in all the temperature regimes with no clear indication of optimum thermal conditions for the GR and GS populations. All populations exhibited considerable germination at the lowest alternating temperature regime 15/5°C (61%, 87%, 49%, and 47% for Ch, SGM2, SGW2, and CP2, respectively), demonstrating the ability of C. virgata to germinate in winter months despite being a summer annual. Seed germination of all populations was inhibited at -0.8 and -1.6 MPa osmotic potential at two alternating temperature regimes (15/5 and 35/25°C); however, some seeds germinated at 25/15°C at -0.8 MPa osmotic potential, indicating the ability of C. virgata to germinate in arid regions and drought conditions. Three biological parameters (T10: incubation period required to reach 10% germination; T50: incubation period required to reach 50% germination; and T90: incubation period required to reach 90% germination) suggested late water imbibition with increasing moisture stress levels. The GR population SGW2 exhibited a distinctive pattern in T10, T50, and T90, possessing delayed germination behaviour and thus demonstrating an escape mechanism against pre-plating weed management practices. Knowledge gained from this study will help in developing site-specific and multi-tactic weed control protocols.
Reactive Oxygen Species (ROS) are continuously produced during seed development, from embryogenesis to germination, but also during seed storage. ROS play a dual role in seed physiology behaving, on ...the one hand, as actors of cellular signaling pathways and, on the other hand, as toxic products that accumulate under stress conditions. ROS, provided that their amount is tightly regulated by the balance between production and scavenging, appear now as being beneficial for germination, and in particular to act as a positive signal for seed dormancy release. Such an effect might result from the interplay between ROS and hormone signaling pathways thus leading to changes in gene expression or in cellular redox status. We also propose that changes in ROS homeostasis would play a role in perception of environmental factors by seeds during their germination, and thus act as a signal controlling the completion of germination. However, uncontrolled accumulation of ROS is likely to occur during seed aging or seed desiccation thus leading to oxidative damage toward a wide range of biomolecules and ultimately to necroses and cell death. We present here the concept of the “oxidative window for germination”, which restricts the occurrence of the cellular events associated with germination to a critical range of ROS level, enclosed by lower and higher limits. Above or below the “oxidative window for germination”, weak or high amounts of ROS, respectively, would not permit progress toward germination.
To cite this article: C. Bailly et al., C. R. Biologies 331 (2008).
Les espèces réactives de l'oxygène (ROS) sont produites continuellement au cours du développement des semences, de l'embryogenèse à la germination, mais aussi au cours de leur stockage. Ces molécules jouent un double rôle dans la physiologie des semences se comportant, d'une part, comme des acteurs des voies de signalisation cellulaire et, d'autre part, comme des produits toxiques s'accumulant sous conditions de stress. Les ROS, à condition que leur niveau d'accumulation soit finement régulé par un équilibre entre production et élimination, apparaissent aujourd'hui être bénéfiques pour la germination et, en particulier, agissent comme signal positif capable de lever la dormance des semences. Un tel effet pourrait résulter de l'interaction entre les ROS et les voies de signalisation hormonales conduisant ainsi à des changements dans l'expression des gènes ou de l'état redox cellulaire. Nous proposons également que les changements dans l'homéostasie des ROS jouent un rôle, pendant la germination, dans la perception par les semences des facteurs environnementaux, et donc agissent comme un signal contrôlant la germination. Toutefois, l'accumulation incontrôlée de ROS est susceptible de se produire au cours du vieillissement des semences ou de leur dessiccation en fin de maturation sur la plante mère, ce qui conduit à des dommages oxydatifs envers un grand nombre de biomolécules et, de manière ultime, à des nécroses et à la mort cellulaire. Nous présentons ici le nouveau concept d'une « fenêtre oxydative pour la germination », qui lie la réalisation d'événements cellulaires associés à la germination à des niveaux critiques de ROS compris entre une limite basse et une limite haute. En deçà ou delà de ces limites, des niveaux trop faibles ou trop élevés de ROS ne permettraient pas la réalisation de la germination.
Pour citer cet article : C. Bailly et al., C. R. Biologies 331 (2008).
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