Efeito de subdoses de 2,4-D sal colina na eficiência quântica do fotossistema II do algodoeiro

Deleterious effects of herbicides on the photochemical apparatus of plants can be quantified by studying the quantum yield potential of photosystem II (Fv/Fm). Therefore, the objective of this work was to evaluate the effect of subdoses of the herbicide 2,4-D choline salt formulation on the quantum efficiency of the photosystem II of cotton plantsat different phenological stages. The study adopted a completely randomized experimental design with seven replications, and the treatments consisted of nine fractions of the average rate indicated on the 2,4-D choline salt herbicide label: 0 (control); 0.4275; 0.855; 1.71; 3.42; 8.55; 17.1; 34.2 and 68.4 g ae ha-1applied at phenological stages V4 or B4 of cotton plants. The plants were evaluated for the visual symptoms of injury and the emission kinetics of maximum chlorophyll a (Fv/Fm) fluorescence at 3, 7 and 14 days after application (DAA) of the herbicide. The values obtained were analyzed by the F test and the effects of the treatments were compared by the Scott-Knott test at 5% probability. The data obtained from visual injury and Fv/Fmwere also submitted to Pearson's correlation. The correlation between visual injury and Fv/Fmin the V4 and B4 stages is negative and significant for both years of conducting the experiment. The Fv/Fmvariable was not affected by the application of subdoses lower than 3.42 g aeha-1of 2,4-D saline choline in the V4 stage and below 1.71 g aeha-1in the B4 stage of the cotton plant.

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Hormesis of 2,4-D Choline Salt in Biometric Aspects of Cotton

Journal of Agricultural Science ◽

10.5539/jas.v11n13p283 ◽

2019 ◽

Vol 11 (13) ◽

pp. 283

Author(s):

Ricardo F. Marques ◽

Sidnei R. Marchi ◽

Guilherme H. R. Pinheiro ◽

Rodrigo M. Souza ◽

Hildeu F. Assunção ◽

...

Keyword(s):

Dose Response ◽

Dry Matter ◽

Average Rate ◽

Response Curves ◽

Cotton Plants ◽

Randomized Experimental Design ◽

Number Of Leaves ◽

Hormesis Effect ◽

Dose Response Curves ◽

High Doses

Plant hormesis is a phenomenon that involves the presence of toxic compounds at high doses but can be beneficial at low doses. Thus, the aim of this study was to use dose-response curves to assess the effect of hormesis caused by sub-toxic of 2,4-D choline herbicide on biometric variables of cotton plants. The study adopted a completely randomized experimental design with seven replications, and the treatments consisted of nine fractions of the average rate indicated on the 2,4-D choline salt herbicide label: 0 (control); 0.4275; 0.855; 1.71; 3.42; 8.55; 17.1; 34.2 and 68.4 g ae ha-1 applied at phenological stages V4 or B4 of cotton plants. The plants were assessed for the main morphological parameters. The results were subjected to analysis of variance and, when significant, the hormesis model was tested aiming to describe the dose-response curves with low rates stimulation. The maximum hormesis effect for the variables plant height and number of leaves in cotton plants at stage V4 was estimated, in due order, for sub-doses between 1.14 and 3.02 and 1.37 and 5.54 g ae ha-1 of 2,4-D choline. The hormesis effect was not significant for total dry matter production when 2,4-D choline was applied at stage V4, irrespective of the year of study. Sub-doses between 0.855 and 1.71 g ae ha-1 of 2,4-D choline salt applied at stage B4 caused hormesis in the height, number of leaves, shoots dry matter and total dry matter of cotton plants.

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Boron-zinc interaction in the absorption of micronutrients by cotton

Agronomía Colombiana ◽

10.15446/agron.colomb.v36n1.66539 ◽

2018 ◽

Vol 36 (1) ◽

pp. 51-57

Author(s):

Érica De Oliveira Araújo ◽

Elcio Ferreira Dos Santos ◽

Marcos Antonio Camacho

Keyword(s):

Experimental Design ◽

Nutrient Solution ◽

Absorption Efficiency ◽

Transport Efficiency ◽

Cu Content ◽

Fe Content ◽

Cotton Plants ◽

Fe And Mn ◽

Randomized Experimental Design ◽

Mn Content

B-Zn interaction modifies the nutritional dynamics of copper (Cu), iron (Fe) and manganese (Mn) in cotton. The main objective of this research was to evaluate the effect of B and Zn concentrations on the absorption of Cu, Fe and Mn in cotton plants grown in a nutrient solution. A completely randomized experimental design with three replicates was performed, in a 4×5 factorial scheme, corresponding to four concentrations of B (0, 20, 40 and 80 μM L-1) and five concentrations of Zn (0, 1, 2, 4 and 8 μM L-1). At 115 days after emergence, the plants were collected, divided into roots, shoots and fruits, and chemically analyzed. The results allowed to conclude that the Cu content and total Cu in the fruit, total Cu in the roots, Cu efficiency, Fe content in the roots, Fe absorption efficiency, Mn content in the fruit, and Mn absorption efficiency of cotton are influenced by the concentrations of B in the solution. The interaction between B and Zn affected the total Fe in the roots, Fe content and total Fe content in the fruit, Fe transport efficiency, total Mn in the shoots and Mn transport efficiency. In addition, Zn acts differently according to the supply of B and vice versa.

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PENGARUH KONSENTRASI RAGI Saccharomyces cerevisiae DAN LAMA FERMENTASI TERHADAP KUALITAS CUKA TOMI-TOMI (Flacourtia inermis)

AGRITEKNO Jurnal Teknologi Pertanian ◽

10.30598/jagritekno.2015.4.2.50 ◽

2015 ◽

Vol 4 (2) ◽

pp. 50-55

Author(s):

Sandra J Nendissa ◽

Rachel Breemer ◽

Nikholaus Melamas

Keyword(s):

Saccharomyces Cerevisiae ◽

Experimental Design ◽

Total Dissolved Solids ◽

Total Sugar ◽

Dissolved Solids ◽

Randomized Experimental Design ◽

Two Factors ◽

Four Levels

This objectives of this research were both to study and determine the best level of concentration of yeast Saccharomyces cereviseae and period of fermentation on the quality of tomi-tomi vinegar (Flacourtia inermis). A completely randomized experimental design with two factors of treatment was applied in this research. The first factor was concentration of yeast S. cereviseae having four levels of tretament, i.e.: without the addition of yeast 0.5, 1 and 1.5 g yeast. The second factor was period fermentation with 1, 2, 3, 4, and 5 weeks. The result indicated that the concentration of yeast S. cereviseae 1.5 g and period fermentation 5 week produced a good tomi-tomi vinegar with total acids 51.22%, total dissolved solids 8.35, total sugar 8.07% and pH 5.40.

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Nitrogen and Phosphorus Addition to Soil Improves Seed Yield, Foliar Stomatal Conductance, and the Photosynthetic Response of Rapeseed (Brassica napus L.)

Agriculture ◽

10.3390/agriculture11060483 ◽

2021 ◽

Vol 11 (6) ◽

pp. 483

Author(s):

Esmaeil Zangani ◽

Kamran Afsahi ◽

Farid Shekari ◽

Eileen Mac Sweeney ◽

Andrea Mastinu

Keyword(s):

Stomatal Conductance ◽

Quantum Yield ◽

Photosystem Ii ◽

Chlorophyll Content ◽

Seed Yield ◽

Nitrogen Application ◽

Flowering Stage ◽

Nitrogen And Phosphorus ◽

Brassica Napus L ◽

Phosphorus Levels

The effects of nitrogen and phosphorus levels on the physiological traits, yield, and seed yield of rapeseed (Brassica napus L.), were studied in a farm research project of Zanjan University. Three levels of nitrogen (0, 100, and 200 kg/ha) and three levels of phosphorus (0, 75, and 150 kg/ha) were considered. The results showed that an increase in nitrogen level caused an increase in the leaf chlorophyll content so that the application of 200 kg/ha of nitrogen increased the chlorophyll content of the leaves until the mid-grain filling stage. Nitrogen application lowered leaf stomatal conductance in the early flowering stage whereas the stomatal conductance was increased during the late flowering stage. Nitrogen application (100 and 200 kg/ha) also increased the quantum yield of photosystem II. On the other hand, with the application of 150 kg/ha and 75 kg/ha of phosphorus, the leaf stomatal conductance and the quantum yield of photosystem II in the early flowering stage increased respectively. The results showed that the application of 200 kg/ha of nitrogen and 75 kg/ha of phosphorus significantly increased seed and oil yield compared to the control. In addition, the number of siliques per plant and the weight of 1000 seeds showed an increasing trend that was affected by nitrogen and phosphorus levels. This study demonstrated that nitrogen enhanced the chlorophyll content, leaf area, and consequently, the quantum yield of photosystem II. Nitrogen also augmented the seed filling duration, seed yield, and oil yield by increasing gas exchange. As a result, the application of 100 kg/ha of nitrogen together with 75 kg/ha phosphorus showed the greatest effect on the qualitative and quantitative yield of rapeseed. However, the application of 200 kg/ha of nitrogen alone or in combination with different levels of phosphorus did not significantly increase many of the studied traits.

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