Direct versus Indirect Herbicide Effects: The Example of Preplant Incorporated Halosulfuron

The potential indirect effects of soil applied herbicides have not been adequately explored. The objective of this study was to explore the potential and relative importance of the indirect effects of halosulfuron applied preplant incorporated (PPI) on several weed species common in white bean fields in Ontario. Halosulfuron applied PPI at 35 g ai ha-1 delayed common lambsquarters and wild mustard emergence and reduced their densities over 70%. It did not delay green foxtail emergence, but the density was decreased over 30%. Indirect herbicidal effects such as delayed emergence timing may be important for weed management in non-competitive crops such as white bean. Based on these results, the indirect effects of soil applied herbicides are real and are potentially important for providing additional prevention of yield loss in field crops. This may be particularly important for relatively non-competitive crops such as white bean and for reducing weed seed return to the seedbank.

Tolerance of Four Market Classes of Dry Beans to Tribenuron and Carfentrazone Applied Preplant

Limited information is available on the sensitivity of dry beans to tribenuron and carfentrazone applied preplant (PP). Four field trials were conducted at Exeter and Ridgetown, ON, Canada in 2019 and 2020 to determine the tolerance of azuki, kidney, small red and white beans to glyphosate (1800 g·ae·ha-1) + tribenuron (15 g·ai·ha-1), glyphosate (1800 g·ae·ha-1) + carfentrazone (35 g·ai·ha-1) and glyphosate (1800 g·ae·ha-1) + tribenuron (15 g·ai·ha-1) + carfentrazone (35 g·ai·ha-1) applied PP 1 - 2 days prior to seeding dry beans. Glyphosate + tribenuron, glyphosate + carfentrazone, and glyphosate + tribenuron + carfentrazone, applied PP, caused 5%, 5% and 9% bean injury at 1 WAE;7%, 6% and 10% bean injury at 2 WAE and 6%, 5% and 8% bean injury at 4 WAE, respectively. At 8 WAE, there was 0, 1% and 4% injury in azuki bean;1%, 2% and 2% injury in kidney bean;3%, 2% and 3% injury in small red bean;and 6%, 3% and 2% injury in white bean with glyphosate + tribenuron, glyphosate + carfentrazone, and glyphosate + tribenuron + carfentrazone applied PP, respectively. The injury was significantly greater with glyphosate + tribenuron in small red and white beans compared to the azuki and kidney beans. There was no difference between injury levels among market classes of dry been with glyphosate + carfentrazone or glyphosate + tribenuron + carfentrazone applied PP. There was no effect of glyphosate + tribenuron, glyphosate + carfentrazone and glyphosate + tribenuron + carfentrazone on dry bean plant stand, maturity and seed yield. However, dry bean biomass was reduced as much as 15% with glyphosate + tribenuron and 13% with glyphosate + tribenuron + carfentrazone compared to the untreated control. Dry bean height was reduced 4% with glyphosate + tribenuron + carfentrazone but was not affected with other treatments. Based on these results, there is potential for using glyphosate plus tribenuron or carfentrazone for preplant weed management in dry bean production.

The Effect of Nitrogen and Phosphorus Ratios and Electrical Conductivity on Plant Growth

Environmental concerns surround the use of plant growth retardants (PGRs) for plant height control, and non-chemical alternatives to PGRs can be labor intensive and expensive. Macronutrient modification is a little-studied, yet potentially effective method of controlling plant height. A number of studies have suggested that phosphorus (P) limitation may restrict plant height. Anecdotal evidence also suggests that using nitrate (NO3-), rather than ammonium (NH4+), as the principal nitrogen (N) source may help control plant height. The primary objective of this study was to evaluate different ratios of NO3-/ NH4+, NO3-/P and NH4+/P as well as electrical conductivity (EC) on plant height and growth. This was tested in a hydroponic system using marigolds, sunflowers and tomatoes. Initially, different ratios were tested at an EC of 1.2 dS·m-1, followed by using the same ratios at four ECs (0.6, 1.2, 2.2 and 4.0 dS·m-1) as a second objective. Although ratios did, at times, limit plant height, responses were season and species dependent, suggesting that modifications in plant nutrition, at the ratios used in this study, may not effectively control plant height in hydroponic systems. More consistent, yet species specific, height control was achieved by increasing EC level.

Structural Characterization of Lignins Isolated from Caragana sinica Using FT-IR and NMR Spectroscopy

In order to efficiently explore and use woody biomass,six lignin fractions were isolated from dewaxed Caragana sinica via successive extraction with organic solvents and alkaline solutions.The lignin structures were characterized by Fourier transform infrared spectroscopy(FT-IR) and 1D and 2D Nuclear Magnetic Resonance(NMR).FT-IR spectra revealed that the "core" of the lignin structure did not significantly change during the treatment under the conditions given.The results of 1H and 13C NMR demonstrated that the lignin fraction L2,isolated with 70% ethanol containing 1% NaOH,was mainly composed of β-O-4 ether bonds together with G and S units and trace p-hydroxyphenyl unit.Based on the 2D HSQC NMR spectrum,the ethanol organosolv lignin fraction L1,extracted with 70% ethanol,presents a predominance of β-O-4′ aryl ether linkages(61% of total side chains),and a low abundance of condensed carbon-carbon linked structures(such as ββ′,β-1′,and β-5′) and a lower S/G ratio.Furthermore,a small percentage(ca.9%) of the linkage side chain was found to be acylated at the γ-carbon.

Soybean (<i>Glycine Max</i>) Leaf Extract Based Green Synthesis of Palladium Nanoparticles

Palladium (Pd) nanoparticles were synthesized using protein rich soybean leaf extract based biological process. Reduction of palladium ions by soybean leaf extract was examined by UV-visible spectroscopic technique. It was believed that the proteins and some of the amino acids that are exist in soybean leaf extracts were actively involved in the reduction of palladium ions. Further it was confirmed by Fourier transformations infrared spectroscopic (FTIR) analysis. These amino acids are not only involving in the reduction of palladium ions but also acting as surfactants that inhibits the rapid agglomeration. The phase purity of the synthesized palladium nanoparticles was investigated through X-Ray Diffraction (XRD) analysis and the obtained pattern was compared with JCPDS data. Transmission electron microscopic (TEM) images of the palladium particles were recorded and the particle size was found to be ~15 nm.

Time of Application of <i>S</i>-Metolachlor Affects Growth, Marketable Yield and Quality of Carrot and Red Beet

Tolerance of carrot and red beet to s-metolachlor at three application timings—pre-emergence to crop (PRE), early postemergence (crop at two to four leaf stage-EPOST), and late postemergence (crop at five to seven leaf stage-LPOST) —was determined from 2008 to 2010. LPOST applications of s-metolachlor reduced carrot above ground plant dry weight, marketable yield and grower payment, but did not affect carrot length. PRE and LPOST applications of s-metolachlor reduced red beet above ground plant dry weight, total marketable yield, yield of No. 2 and No. 3 red beet, and grower payment. Our findings indicate that while carrot may be tolerant to PRE applications of s-metolachlor, applications made after the 5 leaf stage reduced plant dry weight enough to impact marketable yield and grower payment. In red beet, the potential reduction in growth, yield and grade would not justify the utility of a PRE or LPOST applica- tion timing.

Ethephon-Induced Abscission of “Redhaven” Peach

Fruit size of peaches is an important quality factor that can be optimized by adjusting the number of fruit on the tree by hand thinning 40 - 60 days after full bloom (dafb). Hand thinning is labor intensive and therefore the development of other strategies to reduce production cost is warranted. Since ethylene plays a key role in peach fruitlet abscission, it is hypothesized that foliar applications of ethephon will induce fruit abscission and increase fruit size. Ethephon (0 to 400 mg·L–1) was applied to “Redhaven” peach trees 45 - 50 days after full bloom in 2005 and 2007 to determine the efficacy and concentration required to induce fruit abscission. Abscission was linearly related to ethephon concentration and as a result reduced fruit set by 70% to 100 %. These data indicate that ethephon in the range of 100 - 200 mg·L–1 can be used to induce adequate levels of fruit abscission of ‘Redhaven’ peaches without inducing trunk or limb gummosis.

Targeted quantitative profiling of metabolites and gene transcripts associated with 4-aminobutyrate (GABA) in apple fruit stored under multiple abiotic stresses

4-Aminobutyrate accumulates in plants under abiotic stress.Here,targeted quantitative profiling of metabolites and transcripts was conducted to monitor glutamate-and polyamine-derived 4-aminobutyrate production and its subsequent catabolism to succinate or 4-hydroxybutyrate in apple(Malus x domestica Borkh.)fruit stored at 0°C with 2.5 kPa O2 and 0.03 or 5 kPa CO2 for 16 weeks.Low-temperature-induced protein hydrolysis appeared to be responsible for the enhanced availability of amino acids during early storage,and the resulting higher glutamate level stimulated 4-aminobutyrate levels more than polyamines.Elevated CO2 increased the levels of polyamines,as well as succinate and 4-hydroxybutyrate,during early storage,and 4-aminobutyrate and 4-hydroxybutyrate over the longer term.Expression of all of the genes likely involved in 4-aminobutyrate metabolism from glutamate/polyamines to succinate/4-hydroxybutyrate was induced in a co-ordinated manner.CO2-regulated expression of apple GLUTAMATE DECARBOXYLASE 2,AMINE OXIDASE 1,ALDEHYDE DEHYDROGENASE 10A8 and POLYAMINE OXIDASE 2 was evident with longer term storage.Evidence suggested that respiratory activities were restricted by the elevated CO2/O2 environment,and that decreasing NAD+availability and increasing NADPH and NADPH/NADP+,respectively,played key roles in the regulation of succinate and 4-hydroxybutyate accumulation.Together,these findings suggest that both transcriptional and biochemical mechanisms are associated with 4-aminobutyrate and 4-hydroxybutyrate metabolism in apple fruit stored under multiple abiotic stresses.

Control of Glyphosate-Resistant Giant Ragweed (Ambrosia trifida L.) with Isoxaflutole and Metribuzin Tankmix

Five field trials were conducted over a two-year period (2013, 2014) to determine the control of glyphosate-resistant (GR) giant ragweed with isoxaflutole (IFT) and metribuzin (MTZ) applied alone and in combination. Treatments were designed to assess the dose response of an IFT plus MTZ tank-mix as well as each chemical applied alone to classify the response using Flint’s adaptation of Colby’s equation. Two factor factorial experiments were performed in the growth room to ascertain the response of IFT versus glyphosate, IFT versus MTZ, and IFT plus MTZ versus glyphosate on single plants. Field experiments evaluated the control of GR giant ragweed with IFT plus MTZ in tank-mix in a 1:4 ratio. The rate of IFT plus MTZ for 80% control of GR giant ragweed at 4 and 8 weeks after application (WAA) was 518 (104 g a.i. ha-1 IFT + 414 g a.i. ha-1 MTZ) and 631 g a.i. ha-1 (126 g a.i. ha-1 IFT + 505 g a.i. ha-1 MTZ), respectively. A rate of 668 and 467 g a.i. ha-1 was required to reduce GR giant ragweed density and biomass by 80%, respectively. Field experiments evaluating the control of GR giant ragweed with tank-mixes of IFT plus MTZ, where glyphosate was a constant tank-mix partner, were mostly synergistic. However, the low tank-mix rate (52.5 + 210 g a.i. ha-1) had an additive response for GR giant ragweed biomass reduction. When tested in the greenhouse and growth room, glyphosate susceptible (GS) giant ragweed showed some antagonism with glyphosate and isoxaflutole tank-mixes at rates less than commercial field rates. GR giant ragweed showed an additive response across all treatments in the growth room. Greenhouse experiments evaluating IFT versus MTZ and IFT plus MTZ versus glyphosate revealed all tank-mix treatments to be synergistic at 2 WAA.

Green Process for Impregnation of Silver Nanoparticles into Microcrystalline Cellulose and Their Antimicrobial Bionanocomposite Films

A novel greener method to impregnate silver nanoparticles (AgNPs) into microcrystalline cellulose (MCC) by curry leaf (Murraya koenigii) extract mediated biological process is presented. The active reduction of silver ions by curry leaf extract was explored for the in situ impregnation AgNPs into MCC. Transmission electron microscopy (TEM) analyses of MCC coated with AgNPs showed the formation of silver particle sizes in the range of 10-25 nm and have a spherical shape. Further the, EDS analysis of MCC/Ag nanocomposite confirms the formation of Ag structure on microcrystalline cellulose. Solvent casting of poly(lactic-acid) was used to produce composite films containing silver impregnated MCC aiming for antimicrobial applications.

QTL analysis of soft scald in two apple populations

The apple(Malus×domestica Borkh.)is one of the world’s most widely grown and valuable fruit crops.With demand for apples year round,storability has emerged as an important consideration for apple breeding programs.Soft scald is a cold storage-related disorder that results in sunken,darkened tissue on the fruit surface.Apple breeders are keen to generate new cultivars that do not suffer from soft scald and can thus be marketed year round.Traditional breeding approaches are protracted and labor intensive,and therefore marker-assisted selection(MAS)is a valuable tool for breeders.To advance MAS for storage disorders in apple,we used genotyping-by-sequencing(GBS)to generate high-density genetic maps in two F1 apple populations,which were then used for quantitative trait locus(QTL)mapping of soft scald.In total,900 million DNA sequence reads were generated,but after several data filtering steps,only 2%of reads were ultimately used to create two genetic maps that included 1918 and 2818 single-nucleotide polymorphisms.Two QTL associated with soft scald were identified in one of the bi-parental populations originating from parent 11W-12-11,an advanced breeding line.This study demonstrates the utility of next-generation DNA sequencing technologies for QTL mapping in F1 populations,and provides a basis for the advancement of MAS to improve storability of apples.

Response of Underseeded Red Clover(Trifolium pratense L.)to Winter Wheat(Triticum aestivum L.)Herbicides as Affected by Application Timing

Underseeding red clover in winter wheat is a beneficial agronomic practice. Still, many growers tend to forgo this approach. One reason is that herbicides used on winter wheat may injure underseeded red clover, reducing its biomass and the subsequent benefits it provides. Therefore, the effect of winter wheat herbicides on underseeded red clover needs to be evaluated. The objectives of this research were to assess the crop tolerance of underseeded red clover to ten winter wheat herbicides used in Ontario, Canada and determine if red clover tolerance differed when the herbicides were applied at various winter wheat growth stages. Experiments were conducted in 2009 and 2010 at four different Ontario locations. Each herbicide treatment was either applied at an early, normal or late timing. Overall, red clover was not affected by herbicides applied at the early timing. The likelihood of herbicides causing injury and reducing biomass of underseeded red clover increased when they were applied at the more advanced winter wheat growth stages. If timing is a constraint, the three herbicides bromoxynil/MCPA, tralkoxydim, and fenoxaprop-pethyl are the safest to use on red clover underseeded to winter wheat. The remaining herbicides 2,4-D, dicamba/MCPA/mecoprop, dichlorprop/2,4-D, thifensulfuron/ tribenuron + MCPA, fluroxypyr + MCPA, pyrasulfotole/bromoxynil, and prosulfuron + bromoxynil are more injurious, with the last two being the most harmful. By having identified the least damaging herbicides on underseeded red clover in winter wheat and the optimal timing for herbicide application, growers are more likely to adopt this beneficial agronomic practice, save on fertilizer costs and improve soil quality.

Transgene Homozygosity Following Particle Bombardment of Haploid Barley Microspores

Information from previously published studies that are basic to this study is: 1) Following isolated barley microspore culture, around 80% of the resulting barley plants are completely fertile and genetically

Weed Control, Environmental Impact, and Net-Profit of Two-Pass Weed Management Strategies in Dicamba-Resistant Soybean (<i>Glycine max</i>) Using Conventional Tillage

Traditional two-pass weed management strategies need to be compared with new strategies in glyphosate/dicamba-resistant soybean. Weed control, soybean yield, partial profitability and environmental impact (EI) were evaluated in glyphosate/dicamba-resistant soybean using dicamba applied alone or in a tank-mix with dimethenamid-P applied preemergence (PRE). Trials were conducted at three locations during 2014 and 2015. Several PRE herbicides provided excellent control of broadleaf and grass weeds. Dicamba provided > 91% control of broadleaf weeds, and the addition of dimethenamid-P improved grass control. All weed species at the trial locations were controlled > 94% following a postemergence (POST) application of glyphosate. Weed interference reduced soybean seed yield 33% where no herbicide was applied. A single POST application of glyphosate had the lowest EI. Several treatments improved early-season weed control and reduced early-season weed density and biomass compared to glyphosate and had similar EI values. In this study, there was no benefit to yield or partial profit by including a PRE herbicide for weed management;however, the inclusion of multiple modes-of-action in a herbicide program may reduce the selection for herbicide-resistant weeds.

The Effect of Potato Varieties and Processing Methods on Glycemic Response

In order to identify those potatoes which exert a low glycemic impact after processing, eight early potato varieties and four processing methods were evaluated for their total starch content, amylose content, rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS), estimated glycemic index (eGI), glycemic load (eGL) as well as their relationship among each other. While all these profiles were highly dependent on the potato variety and processing methods, all the eight varieties were classified as low GL foods (p ≤ 0.05). A strong positive correlation was observed between eGI and RDS (r = 0.84, 0.79, and 0.74) for retrograded and reheated, baked and microwaved varieties, respectively), whereas a moderate negative correlation was observed between eGI and RS for retrograded and reheated (r = -0.39) and microwaved (-0.37) varieties (p ≤ 0.05). On the basis of these findings, it can be concluded that potato variety, processing methods, and starch characteristics define the eGI and eGL. Furthermore, for the varieties examined, the present study identified RDS as a major starch factor contributing to eGI.

Biologically-Effective-Dose of Tolpyralate and Tolpyralate plus Atrazine for Control of Multiple-Herbicide-Resistant Waterhemp [<i>Amaranthus tuberculatus</i>(Moq.) J. D. Sauer] in Corn

The biologically-effective-dose of tolpyralate, a new 4-hydroxyphenyl-pyruvate dioxygenase (HPPD)-inhibitor, applied alone or tank-mixed with atrazine, for the control of multiple-herbicide-resistant (MHR) waterhemp [Amaranthus tuberculatus (Moq.) J. D. Sauer] has not been studied in corn. Seven field experiments were conducted during a three-year period (2018, 2019, 2020) in Ontario, Canada with MHR waterhemp to determine: 1) the dose-response of MHR waterhemp to tolpyralate and tolpyralate plus atrazine, and 2) the relative efficacy of tolpyralate and tolpyralate plus atrazine to post-emergence corn herbicides, dicamba/atrazine (500/1000 g·ha−1) and mesotrione + atrazine (100 + 280 g·ha−1). Tolpyralate + atrazine (120 + 4000 g·ha−1) caused 13% corn injury at one site two weeks after application (WAA), which was observed as transient foliar chlorosis and bleaching of new leaves. At 12 WAA, the predicted dose of tolpyralate for 50% control of MHR waterhemp at Cottam and on Walpole Island was 8 and 2 g·ha−1, respectively;the predicted dose of tolpyralate + atrazine for 50% control of MHR waterhemp at Cottam and on Walpole Island was 5 + 160 and 1 + 21 g·ha−1, respectively. The difference in predicted dose at the two sites is likely due to differences in MHR density and resistance profile. Applied at the registered rate, tolpyralate (30 g·ha−1) and tolpyralate + atrazine (30 + 1000 g·ha−1) controlled MHR waterhemp similar to dicamba/atrazine and mesotrione + atrazine across sites. This study demonstrates that tolpyralate + atrazine, applied POST, provides season-long control of MHR waterhemp in corn.

Early Postemergence Herbicide Tank-Mixtures for Control of Waterhemp Resistant to Four Herbicide Modes of Action in Corn

Multiple-herbicide-resistant (MHR) waterhemp has been confirmed and is difficult to control for growers in Ontario, Canada and in the Midwestern United States. The objective of this study was to evaluate early post-emergence (EPOST) herbicides for control of MHR waterhemp in field corn. Five field trials were conducted over a two-year period (2019, 2020) at sites on Walpole Island, ON and near Cottam, ON, Canada. Thirteen herbicide tank-mixtures containing multiple modes-of-action (MOA) were applied EPOST to 5 cm MHR waterhemp in field corn. Control of MHR waterhemp varied by site due to variable plant density, plant biomass, and number of herbicide-resistant individuals across research sites and years. Control of MHR waterhemp ranged from 90% to 100% with glyphosate + S-metolachlor/mesotrione/ bicyclopyrone/atrazine, glyphosate/2,4-D choline + rimsulfuron + mesotrione + atrazine, glyphosate + S-metolachlor/atrazine/mesotrione, glyphosate + mesotrione + atrazine, glyphosate/S-metolachlor/mesotrione + atrazine, glyphosate + S-metolachlor/mesotrione/bicyclopyrone, glyphosate/2,4-D choline + rimsulfuron + mesotrione, and glyphosate + pyroxasulfone + dicamba/atrazine at 4, 8, and 12 WAA. Control of MHR waterhemp ranged from 70% to 100% with glyphosate + topramezone/dimethenamid-P + dicamba/atrazine, glyphosate + isoxaflutole + atrazine, and glyphosate + tolpyralate + atrazine at 4, 8, and 12 WAA. Control of MHR waterhemp was similar for all herbicide programs, except glyphosate + dicamba/atrazine and glyphosate + S-metolachlor/atrazine which resulted in the lowest control at three of five sites that ranged from 63% to 89% and 61% to 76%, respectively. Crop injury was ≤10% for herbicide programs tested, except 28% to 31% corn injury with glyphosate/2,4-D choline + rimsulfuron + mesotrione + atrazine;however, without effect on corn grain yield. Corn yield was comparable with all herbicide programs evaluated in this study. It is concluded that there are herbicide programs that provide control of emerged and full-season residual control of MHR waterhemp in field corn.

Protein and Phenolic Contents and Antioxidant Activities of 14 Early Maturing Potatoes as Affected by Processing

The effects of processing and genotype (fourteen early potato varieties) were evaluated for their phytochemicals, total phenolics (TPC), total flavonoids (TFC), total anthocyanins (TAC), antioxidant activities measured by ORAC, FRAP and DPPH assays and protein content. While all these profiles were highly dependent on the potato variety and processing, F09085, F10090, French Fingerlings, Purple Fiesta, Red Thumb, Ciklamen and Norland were identified as nutritionally rich in phytochemicals such as TPC, TFC, TAC, higher antioxidant capacities and protein (p p p < 0.0001).

Engineered Cleistogamy in Camelina sativa for bioconfinement

Camelina sativa is a self-pollinating and facultative outcrossing oilseed crop.Genetic engineering has been used to improve camelina yield potential for altered fatty acid composition,modified protein profiles,improved seed and oil yield,and enhanced drought resistance.The deployment of transgenic camelina in the field posits high risks related to the introgression of transgenes into nontransgenic camelina and wild relatives.Thus,effective bioconfinement strategies need to be developed to prevent pollen-mediated gene f low(PMGF)from transgenic camelina.In the present study,we overexpressed the cleistogamy(i.e.f loral petal non-openness)-inducing PpJAZ1 gene from peach in transgenic camelina.Transgenic camelina overexpressing PpJAZ1 showed three levels of cleistogamy,affected pollen germination rates after anthesis but not during anthesis,and caused a minor silicle abortion only on the main branches.We also conducted field trials to examine the effects of the overexpressed PpJAZ1 on PMGF in the field,and found that the overexpressed PpJAZ1 dramatically inhibited PMGF from transgenic camelina to non-transgenic camelina under the field conditions.Thus,the engineered cleistogamy using the overexpressed PpJAZ1 is a highly effective bioconfinement strategy to limit PMGF from transgenic camelina,and could be used for bioconfinement in other dicot species.

植物代谢组学研究进展(英文)

代谢组学是继基因组学、转录组学和蛋白质组学之后发展起来的一门学科,通过对细胞内的基因表达最终代谢产物的定性和定量分析以及定义细胞或器官的生化表现类型来解释功能基因的表达过程.文中就代谢组学的发展历史、主要研究内容、技术特点、数据处理过程及在植物领域中的应用的最新进展几方面进行阐述,以供读者参考.