Impact of Roundup 41% aqua on physiological index of soybean at one-trifoliolate leaf stage

A field experiment was conducted in 2017 and 2018 to evaluate the sensitivity and recovery of grain sorghum to the simulated drift of glufosinate, glyphosate, and paraquat at two application timings (V6 and flag leaf growth stage). Paraquat drift caused maximum injury to sorghum plants in both years, whereas the lowest injury was caused by glyphosate in 2017. Averaged over all herbicide treatments, injury to grain sorghum from the simulated herbicide drift was 5% greater when herbicides were applied at flag leaf stage, as compared to herbicide applications at the six-leaf stage in 2017. In 2018, injury from glyphosate drift was higher when applied at the six-leaf stage than at the flag leaf stage. Paraquat and glufosinate drift caused more injury when applied at flag leaf stage than at six-leaf stage at 14 days after application in 2018. About 21% to 29% of injury from the simulated drift of paraquat led to a 31% reduction in grain sorghum yield, as compared to a nontreated check in 2017. The simulated drift of glyphosate and glufosinate did not result in any significant yield reduction compared to the nontreated check in 2017, possibly due to the recovery of sorghum plants after herbicides’ drift application.

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Nitrogen Supply Affects Grain Yield by Regulating Antioxidant Enzyme Activity and Photosynthetic Capacity of Maize Plant in the Loess Plateau

Agronomy ◽

10.3390/agronomy11061094 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1094

Author(s):

Kai Yue ◽

Lingling Li ◽

Junhong Xie ◽

Setor Kwami Fudjoe ◽

Renzhi Zhang ◽

...

Keyword(s):

Grain Yield ◽

Antioxidant Enzyme ◽

Loess Plateau ◽

Photosynthetic Capacity ◽

Growth And Yield ◽

Dry Matter Accumulation ◽

The Loess Plateau ◽

Area Index ◽

Leaf Stage ◽

Significant Difference

Nitrogen (N) is the most limiting nutrient for maize, and appropriate N fertilization can promote maize growth and yield. The effect of N fertilizer rates and timings on morphology, antioxidant enzymes, and grain yield of maize (Zea mays L.) in the Loess Plateau of China was evaluated. The four N levels, i.e., 0 (N0), 100 (N1), 200 (N2), and 300 (N3) kg ha−1, were applied at two timings (T1, one-third N at sowing and two-thirds at the six-leaf stage of maize; T2, one-third applied at sowing, six-leaf stage, and eleven-leaf stage of maize). The results show that N2 and N3 significantly increased the plant height, stem and leaf dry weight, and leaf area index of maize compared with a non-N-fertilized control (N0). The net photosynthetic rate, transpiration rate, stomatal conductance, and leaf chlorophyll contents were lower, while the intercellular carbon dioxide concentration was higher for non-fertilized plants compared to fertilized plants. The activities of peroxidase (POD) and superoxide dismutase (SOD) increased with N rate, but the difference between 200 and 300 kg ha−1 was not significant; further, the isozyme bands of POD and SOD also changed with their activities. Compared with a non-N-fertilized control, N2 and N3 significantly increased grain yield by 2.76- and 3.11-fold in 2018, 2.74- and 2.80-fold in 2019, and 2.71- and 2.89-fold in 2020, and there was no significant difference between N2 and N3. N application timing only affected yield in 2018. In conclusion, 200 kg N ha−1 application increased yield through optimizing the antioxidant enzyme system, increasing photosynthetic capacity, and promoting dry matter accumulation. Further research is necessary to evaluate the response of more cultivars under more seasons to validate the results obtained.

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Quantitative Response of Maize Vcmax25 to Persistent Drought Stress at Different Growth Stages

Water ◽

10.3390/w13141971 ◽

2021 ◽

Vol 13 (14) ◽

pp. 1971

Author(s):

Xingyang Song ◽

Guangsheng Zhou ◽

Qijin He ◽

Huailin Zhou

Keyword(s):

Drought Stress ◽

Early Warning Systems ◽

Growth And Yield ◽

Leaf Water Content ◽

Growth Stages ◽

Leaf Stage ◽

Maximum Value ◽

Maize Varieties ◽

Persistent Drought ◽

Different Growth Stages

Drought stress has adverse effects on crop growth and yield, and its identification and monitoring play vital roles in precision crop water management. Accurately evaluating the effect of drought stress on crop photosynthetic capacity can provide a basis for decisions related to crop drought stress identification and monitoring as well as drought stress resistance and avoidance. In this study, the effects of different degrees of persistent drought in different growth stages (3rd leaf stage, 7th leaf stage and jointing stage) on the maximum carboxylation rate at a reference temperature of 25 °C (Vcmax25) of the first fully expanded leaf and its relationship to the leaf water content (LWC) were studied in a field experiment from 2013 to 2015. The results indicated that the LWC decreased continuously as drought stress continued and that the LWC decreased faster in the treatment with more irrigation. Vcmax25 showed a decreasing trend as the drought progressed but had no clear relationship to the growth stage in which the persistent drought occurred. Vcmax25 showed a significantly parabolic relationship (R2 = 0.701, p < 0.001) with the LWC, but the different degrees of persistent drought stress occurring in different growth stages had no distinct effect on the LWC values when Vcmax25 reached its maximum value or zero. The findings of this study also suggested that the LWC was 82.5 ± 0.5% when Vcmax25 reached its maximum value (42.6 ± 3.6 μmol m−2 s−1) and 67.6 ± 1.2% (extreme drought) when Vcmax25 reached zero. These findings will help to improve crop drought management and will be an important reference for crop drought identification, classification and monitoring as well as for the development of drought monitoring and early warning systems for other crops or maize varieties.

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TCT-343 IFR PLUS INTRACORONARY NITROGLYCERINE: A NEW PHYSIOLOGICAL INDEX OF LESION SEVERITY

Journal of the American College of Cardiology ◽

10.1016/j.jacc.2014.07.388 ◽

2014 ◽

Vol 64 (11) ◽

pp. B99

Author(s):

Javier Cuesta ◽

Fernando Rivero-Crespo ◽

Teresa Bastante-Valiente ◽

Amparo Benedicto ◽

Guillermo Diego-Nieto ◽

...

Keyword(s):

Physiological Index ◽

Lesion Severity

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Performance of 7 Australian native grasses from the temperate zone under a range of cutting and fertiliser regimes

Crop and Pasture Science ◽

10.1071/cp09067 ◽

2009 ◽

Vol 60 (10) ◽

pp. 943 ◽

Cited By ~ 11

Author(s):

Z. N. Nie ◽

R. P. Zollinger ◽

J. L. Jacobs

Keyword(s):

Root Biomass ◽

Native Species ◽

High Fertility ◽

Native Grasses ◽

Compost Tea ◽

Plant Survival ◽

Leaf Stage ◽

Fertiliser Application ◽

Cutting Intensity ◽

Weeping Grass

This glasshouse study aimed to examine the performance of 7 Australian native grasses and their responses to different cutting and fertiliser regimes. The 7 native grasses comprised 2 wallaby grasses (Austrodanthonia bipartita cv. Bunderra and Austrodanthonia setacea, Woodhouse ecotype), 2 weeping grasses (Microlaena stipoides cv. Bremmer and ecotype Coleraine), 1 spear grass (Austrostipa mollis, ecotype Lexton), 1 red-leg grass (Bothriochlora macra, ecotype Hamilton), and 1 kangaroo grass (Themeda triandra, ecotype Yass). For each of the 7 grasses, 64 pots each containing 9 plants were arranged in a 4 cutting intensity × 4 fertiliser level factorial design with 4 replicates. The cutting intensity treatments involved (1) cutting to 2 cm at 3–5-week intervals; (2) cutting to 5 cm at 3–5-week intervals; (3) cutting to 10 cm at 3–5-week intervals; and (4) cutting to 2 cm based on leaf stage. The fertiliser regimes included low, medium, and high fertility treatments by applying various rates of phosphorus, and the treatment with addition of compost tea. Herbage accumulation, shoot and root growth, plant survival and tiller density, nutritive characteristics, and leaf stage were monitored. All grass lines produced the lowest herbage mass when cut to 2 cm above ground at 3–5-week intervals. Cutting to 5 cm or to 2 cm based on leaf stage favoured herbage accumulation of Lexton spear grass, Hamilton red grass, Yass kangaroo grass, and Coleraine weeping grass. Cutting to 10 cm favoured herbage accumulation of Bremmer weeping grass and wallaby grass. Cutting to 10 cm together with high fertiliser application considerably increased herbage accumulation in comparison with treatments with low fertiliser application or with compost tea. Shoot and root biomass were maximised when plants were cut to 10 cm above ground, except Lexton spear grass which had highest root biomass when plants were managed based on leaf stage. Plant survival was dramatically affected by defoliation intensity and varied among species. Plant survival declined when plants were cut to 2 cm above ground for most species. Overall, native grasses were considered to have good nutritive characteristics with crude protein ranging from 17 to 22% and neutral detergent fibre from 48 to 60%. Results from this study indicate that it may be possible to use leaf stage as a determinant for the commencement of grazing native species. Optimum leaf stages that could be used as a grazing management guide were on average 3.4 for wallaby grass, 4.2 for weeping grass, 3 for spear grass, 3.8 for red-leg grass, and 4.4 for kangaroo grass. However, further work is required to better define this for likely seasonal variation between C3 and C4 species.

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Absorption, Translocation, and Metabolism of14C-Glufosinate in Glufosinate-Resistant Corn, Goosegrass (Eleusine indica), Large Crabgrass (Digitaria sanguinalis), and Sicklepod (Senna obtusifolia)

Weed Science ◽

10.1614/ws-08-089.1 ◽

2009 ◽

Vol 57 (1) ◽

pp. 1-5 ◽

Cited By ~ 23

Author(s):

Wesley J. Everman ◽

Cassandra R. Mayhew ◽

James D. Burton ◽

Alan C. York ◽

John W. Wilcut

Keyword(s):

Weed Species ◽

Digitaria Sanguinalis ◽

Eleusine Indica ◽

Leaf Stage ◽

Senna Obtusifolia ◽

Harvest Timing ◽

Treated Leaf ◽

Harvest Intervals ◽

Corn Plants ◽

Large Crabgrass

Greenhouse studies were conducted to evaluate14C-glufosinate absorption, translocation, and metabolism in glufosinate-resistant corn, goosegrass, large crabgrass, and sicklepod. Glufosinate-resistant corn plants were treated at the four-leaf stage, whereas goosegrass, large crabgrass, and sicklepod were treated at 5, 7.5, and 10 cm, respectively. All plants were harvested at 1, 6, 24, 48, and 72 h after treatment (HAT). Absorption was less than 20% at all harvest intervals for glufosinate-resistant corn, whereas absorption in goosegrass and large crabgrass increased from approximately 20% 1 HAT to 50 and 76%, respectively, 72 HAT. Absorption of14C-glufosinate was greater than 90% 24 HAT in sicklepod. Significant levels of translocation were observed in glufosinate-resistant corn, with14C-glufosinate translocated to the region above the treated leaf and the roots up to 41 and 27%, respectively. No significant translocation was detected in any of the weed species at any harvest timing. Metabolites of14C-glufosinate were detected in glufosinate-resistant corn and all weed species. Seventy percent of14C was attributed to glufosinate metabolites 72 HAT in large crabgrass. Less metabolism was observed for sicklepod, goosegrass, and glufosinate-resistant corn, with metabolites composing less than 45% of detectable radioactivity 72 HAT.

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SEEDLING PUBESCENCE AS A GENETIC MARKER IN SMOOTH BROMEGRASS (BROMUS INERMIS LEYSS.)

Canadian Journal of Plant Science ◽

10.4141/cjps80-169 ◽

1980 ◽

Vol 60 (4) ◽

pp. 1163-1170 ◽

Cited By ~ 3

Author(s):

R. P. KNOWLES

Keyword(s):

Genetic Marker ◽

North American ◽

Inbred Lines ◽

Bromus Inermis ◽

Mass Selection ◽

Smooth Bromegrass ◽

Leaf Stage ◽

Temperature Conditions ◽

Early Fall ◽

Controlled Crosses

Seedlings of a group of North American cultivars of smooth bromegrass were examined at the three-leaf stage for pubescence under greenhouse conditions. Southern strains showed 90–98% strongly pubescent seedlings while northern strains had 60–70% strongly pubescent seedlings. Saratoga, although considered southern in type, was less pubescent than all other cultivars except Polar. The degree of pubescence was greater in spring and early fall plantings than in winter plantings, indicating that pubescence depends on good light and temperature conditions. Strains nearly pure for strong pubescence were formed by repeated cycles of mass selection. Few inbred lines showed uniformity for pubescent or smooth seedlings. Pure-breeding smooth stocks were more difficult to produce than highly pubescent strains. Controlled crosses showed partial dominace for pubescence and little difference between reciprocals. Adjacent plantings of pubescent and smooth seedling stocks showed as much as 45% off-type seedlings from seed produced at the interface of plots. Contamination declined to 10% or less at 10 m from the border.

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The Influence of Chlorophenoxy Herbicides MCPA on Creeping Bentgrass Physiological Index

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.356-360.2763 ◽

2011 ◽

Vol 356-360 ◽

pp. 2763-2766 ◽

Cited By ~ 1

Author(s):

Yang Fan Gao ◽

Ming Wang Shi ◽

Jian Hua Wang

Keyword(s):

Chlorophyll Content ◽

Sugar Content ◽

Soluble Sugar ◽

Creeping Bentgrass ◽

Physiological Index ◽

Soluble Sugar Content ◽

Content Determination ◽

Chlorophenoxy Herbicides ◽

Test Result

In this article, we studied to different concentrations of MCPA to creeping bentgrass Growth. Through the creeping bentgrass in four different periods of chlorophyll content, MDA and soluble sugar content determination. This test result showed:With the MCPA concentration increases, creeping bentgrass decline of chlorophyll content in the same period of growth, MDA and soluble sugar content increased. MCPA used after the early pair of creeping bentgrass growth is large, to put off with MCPA handle time, to affect to creeping bentgrass growth is gradually decreased.

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Integrating Economics in the Critical Period for Weed Control Concept in Corn

Weed Science ◽

10.1614/ws-d-13-00184.1 ◽

2014 ◽

Vol 62 (4) ◽

pp. 608-618 ◽

Cited By ~ 3

Author(s):

Martina Keller ◽

Geoffroy Gantoli ◽

Jens Möhring ◽

Christoph Gutjahr ◽

Roland Gerhards ◽

...

Keyword(s):

Weed Control ◽

Critical Period ◽

Logistic Models ◽

Crop Growth ◽

Growth Stages ◽

Corn Yield ◽

Leaf Stage ◽

Weed Interference ◽

Free Interval ◽

Crop Growth Stages

The effect of weed interference on corn yield and the critical period for weed control (CPWC) were determined in Germany and Benin. Treatments with weed control starting at different crop growth stages and continuously kept weed-free until harvest represented the “weed-infested interval.” Treatments that were kept weed-free from sowing until different crop growth stages represented the “weed-free interval.” Michaelis–Menten, Gompertz, logistic and log–logistic models were employed to model the weed interference on yield. Cross-validation revealed that the log–logistic model fitted the weed-infested interval data equally well as the logistic and slightly better than the Gompertz model fitted the weed-free interval. For Benin, economic calculations considered yield revenue and cost increase due to mechanical weeding operations. Weeding once at the ten-leaf stage of corn resulted already profitable in three out of four cases. One additional weeding operation may optimize and assure profit. Economic calculations for Germany determined a CPWC starting earlier than the four-leaf stage, challenging the decade-long propagated CPWC for corn. Differences between Germany and Benin are probably due to the higher yields and high costs in Germany. This study provides a straightforward method to implement economic data in the determination of the CPWC for chemical and nonchemical weed control strategies.

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Control of Volunteer Glyphosate-Resistant Canola in Glyphosate-Resistant Sugar Beet

Weed Technology ◽

10.1614/wt-d-14-00059.1 ◽

2015 ◽

Vol 29 (1) ◽

pp. 93-100 ◽

Cited By ~ 3

Author(s):

Vipan Kumar ◽

Prashant Jha

Keyword(s):

Sugar Beet ◽

Field Experiments ◽

Agricultural Research ◽

Effective Control ◽

Additional Advantage ◽

Leaf Stage ◽

Beet Root ◽

Control Volunteer ◽

Sugar Beet Root ◽

Herbicide Programs

Occurrence of glyphosate-resistant (GR) canola volunteers in GR sugar beet is a management concern for growers in the Northern Great Plains. Field experiments were conducted at the Southern Agricultural Research Center near Huntley, MT, in 2011 and 2012 to evaluate effective herbicide programs to control volunteer GR canola in GR sugar beet. Single POST application of triflusulfuron methyl alone at the two-leaf stage of sugar beet was more effective at 35 compared with 17.5 g ai ha−1. However, rate differences were not evident when triflusulfuron methyl was applied as a sequential POST (two-leaf followed by [fb] six-leaf stage of sugar beet) program (17.5 fb 17.5 or 35 fb 35 g ha−1). Volunteer GR canola plants in the sequential POST triflusulfuron methyl–containing treatments produced little biomass (11 to 15% of nontreated plots) but a significant amount of seeds (160 to 661 seeds m−2). Ethofumesate (4,200 g ai ha−1) PRE followed by sequential POST triflusulfuron methyl (17.5 or 35 g ha−1) provided effective control (94 to 98% at 30 d after treatment [DAT]), biomass reduction (97%), and seed prevention of volunteer GR canola. There was no additional advantage of adding either desmedipham + phenmedipham + ethofumesate premix (44.7 g ha−1) or ethofumesate (140 g ha−1) to the sequential POST triflusulfuron methyl–only treatments. The sequential POST ethofumesate-only (140 fb 140 g ha−1) treatment provided poor volunteer GR canola control at 30 DAT, and the noncontrolled plants produced 6,361 seeds m−2, which was comparable to the nontreated control (7,593 seeds m−2). Sequential POST triflusulfuron methyl–containing treatments reduced GR sugar beet root and sucrose yields to 18 and 20%, respectively. Consistent with GR canola control, sugar beet root and sucrose yields were highest (95 and 91% of hand-weeded plots, respectively) when the sequential POST triflusulfuron methyl–containing treatments were preceded by ethofumesate (4,200 g ha−1) PRE. Growers should utilize these effective herbicide programs to control volunteer GR canola in GR sugar beet. Because of high canola seed production potential, as evident from this research, control efforts should be aimed at preventing seed bank replenishment of the GR canola volunteers.

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