scholarly journals Far Red and Red as Factors Forming Physiological Processes in Spring Barley under Controlled Conditions

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2007
Author(s):  
Andrzej Doroszewski ◽  
Teresa Doroszewska ◽  
Anna Podleśna

Solar radiation is a very important energy source for life on Earth and especially for the proper growth and development of plants. Its spectral composition is necessary for a main physiological process in a plant’s life—photosynthesis. In practical agriculture, plants are cultivated in the stand, which causes neighboring plants not only to compete for water and nutrients but also for light. Living in such an environment, plants have developed different mechanisms for dealing with shading. An aim of the studies conducted here was to determine the effect of the red (R) and far red (FR) range of spectral composition on gas exchange and the other physiological features of spring barley plants. The experiment was conducted in two growth chambers with different spectral compositions of radiation. Spring barley was grown in Mitscherlich pots. The physiological features measured during the two barley developmental phases, i.e., seventh and flag leaves, differed depending on the R/FR ratio used in these chambers. Plants that grew under conditions of a high R/FR ratio showed a higher photosynthesis efficiency, intracellular CO2 concentration, stomatal conductance and transpiration of water but lower values of the water use efficiency (WUE) index. The leaves of plants treated with this kind of light (higher R/FR ratio) had a greater stomata number and higher content of chlorophyll when compared to plants grown under conditions with a low R/FR ratio.

2020 ◽  
pp. 1961-1969
Author(s):  
Pedro Henrique Oliveira Simões ◽  
João Olegário Pereira de Carvalho ◽  
Dênmora Gomes de Araujo ◽  
Marcos André Piedade Gama ◽  
Clenes Cunha Lima ◽  
...  

Tachigali vulgaris L. G. Silva & H. C. Lima is a pioneer species with great potential for reforestation. The inadequate supply of phosphorus and potassium results in nutritional disorders, requiring nutritional complementation. This study aimed to evaluate the effect of phosphorus (P) and potassium (K) doses on Tachigali vulgaris gas exchange. Three doses of P (0, 26.7 and 53.5 kg-1 ha) and three doses of K (0, 50 and 100 kg-1 ha) were applied in a 3x3 factorial scheme as randomized block design. The data were submitted to analysis of variance using the Tukey 1% test and Pearson's linear correlation test. Potassium fertilization provided increases of approximately 30% in the rate of liquid photosynthesis (PN). Stomata conductance (GS), internal CO2 concentration (Ci), perspiration (E), instantaneous caboxilation efficiency (ΦC), water use efficiency (EWU) and intrinsic water use efficiency (iEWU) were also favored at dose of 78.2 g kg-1 K, suggesting their role in regulating essential physiological processes for plant growth. The highest PN values were observed with application of 33.1 g kg-1 P and 78.2 g kg-1 K, with rates of 4.28 and 4.86 μmol CO2 m-2 s-1, respectively, which also occurred with E, ΦC, EWU and iEWU. It was observed that P exerted antagonistic effects on K absorption, which may also have impaired Mg2+ absorption due to the fact that Ca2+ is an accompanying ion of potassium fertilizer


2021 ◽  
Author(s):  
Ricardo GIL ◽  
Dhikra ZAYOUD ◽  
Zeineb OUERGHI ◽  
Monica BOSCAIU ◽  
Oscar VICENTE ◽  
...  

Abstract Aims The survival and ecological distribution of plants in arid habitats are mainly conditioned by water availability and physiological adaptations to withstand drought. In the present study, we have compared the physiological responses to drought of two Retama raetam (retama) subspecies from Tunisia, one of them living under the desert climate (subsp. raetam) and the other one growing on the coast (subsp. bovei). Methods To physiologically characterize the two R. raetam subspecies, and to elucidate their main mechanisms underlying their tolerance to drought stress, parameters related to seed germination, growth, photosynthesis (net photosynthetic rate, intracellular CO2 concentration, transpiration rate, stomatal conductance and water use efficiency), and accumulation of osmolytes (proline, glycine betaine and soluble sugars) were determined in four-month-old plants subjected to stress for up to one month. Important findings Drought significantly inhibited germination, growth, and all the evaluated photosynthetic parameters. Plants of R. raetam subsp. bovei were severely affected by drought after three weeks of treatment when photosynthesis rates were up to 7-fold lower than in the controls. At the same time, proline and glycine betaine significantly accumulated compared to the irrigated controls, but much less than in R. raetam subsp. raetam; in the latter subspecies, proline and glycine betaine increased to levels 24-fold and 6-fold higher, respectively, than in the corresponding controls. In summary, the population living in the desert region exhibited stronger tolerance to drought stress than that adapted to the semiarid littoral climate, suggesting that tolerance in R. raetam is dependent on accumulation of osmolytes.


2019 ◽  
Vol 11 (8) ◽  
pp. 188
Author(s):  
Lucas Aparecido Manzani Lisboa ◽  
Amanda Stelutti ◽  
Karla Caroline Santana Lima ◽  
Guilherme Bandeca Rafachinho ◽  
Renata Alari Chedid ◽  
...  

Luminosity and temperature are factors that directly act in photosynthetic process, in which the elevation of the light intensity may provoke reduction in the assimilation of carbon, impairing the development of the soybean culture. This work aimed to know physiological parameters of soybean (Glycine max L. Merr.) under different intensities of artificial light. The experiment was carried out in randomized blocks, in a factorial scheme 2 × 5, being two soybean cultivars (Potência and NS6700) and five densities of light: 0 (control), 500, 1000, 1500 and 2000 μmol m-2 s-1 of photosynthetically active radiation (PAR) provided by LED bulbs, with 4 repetitions, in total of 40 plots. The following variables were set: rate of CO2 assimilation (A), transpiration (E), stomatal conductance (gs), inner CO2 concentration in the substomatic chamber (Ci) and water use efficiency (WUE) in which a portable device of gas exchange was used (Infra-Red Gas Analyzer-IRGA, marca ADC BioScientific Ltd, modelo LC-Pro). Seedlings of soybean positively responded under different intensities of artificial light till reach the maximum saturation point between 1400 and 1600 µmol m-1 s-1 of light, which promoted a better rate of A, Ci andWUE. E and gs presented positive linear responses by increasing the intensity of artificial light. The ideal light intensity to the use of Infra-Red Gas Analyzer-IRGA between 1400 and 1600 µmol m-1 s-1 to the soybean culture.


2018 ◽  
Vol 156 (5) ◽  
pp. 628-644 ◽  
Author(s):  
E. Pohanková ◽  
P. Hlavinka ◽  
M. Orság ◽  
J. Takáč ◽  
K. C. Kersebaum ◽  
...  

AbstractIn the current study, simulations by five crop models (WOFOST, CERES-Barley, HERMES, DAISY and AQUACROP) were compared for 7–12 growing seasons of spring barley (Hordeum vulgare) at three sites in the Czech Republic. The aims were to compare how various process-based crop models with different calculation approaches simulate different values of transpiration (Ta) and evapotranspiration (ET) based on the same input data and compare the outputs of these simulations with reference data. From the outputs of each model, the water use efficiency (WUE) from Ta (WUETa) and from actual ET (WUEETa) was calculated for grain yields and above-ground biomass yield. The results of the first part of the study show that the model with the Penman approach for calculating ET simulates lower actual ET (ETa) sums, at an average of 250 mm during the growing season, than other models, which use the Penman–Monteith approach and simulate 330 mm on average during the growing season. In the second part of the current study, WUE reference values in the range 1.9–2.4 kg/m3were calculated for spring barley and grain yield. Values of WUETa/WUEETacalculated from the outputs of individual models for grain yields and above-ground biomass yields ranged from 2.0/1.0 to 5.9/3.8 kg/m3with an average value of 3.2/2.0 kg/m3and from 3.9/2.1 to 10.5/6.8 kg/m3with an average value of 6.5/4.0 kg/m3, respectively. The results confirm that the average values of all models are nearest to actual values.


2018 ◽  
Vol 10 (6) ◽  
pp. 171
Author(s):  
João Everthon da Silva Ribeiro ◽  
Arliston Pereira Leite ◽  
José Eldo Costa ◽  
Manoel Bandeira de Albuquerque ◽  
Fábio Mielezrski

Among nutrients, nitrogen is required in the greatest quantities by bean culture. The objective of this work was to evaluate growth, physiological responses and productivity of the common bean cultivar, ‘IAC Imperador’ under varying nitrogen doses in Brejo Paraibano. The experiment was carried out at Fazenda Experimental Chã-de-Jardim (Chã-de-Jardim Experimental Farm), of the Centro de Ciências Agrárias of the Universidade Federal da Paraíba, in the municipality of Areia, state of Paraíba. The treatments comprised 0, 50, 100, 150 and 200 kg of nitrogen ha-1, applied in coverage at 35 days after sowing. To assess growth, plant height, stem diameter and number of leaves were evaluated. For gas exchange, photosynthesis rate, internal CO2 concentration, transpiration, stomatal conductance, instantaneous water use efficiency and instantaneous carboxylation efficiency were evaluated. For chlorophyll “a” fluorescence, minimum leaf fluorescence, maximum leaf fluorescence, variable maximum fluorescence, potential quantum efficiency of PSII (Photosystem II) and ratio (Fv/F0) were evaluated. For the components of primary productivity, the height of insertion of the first pod, number of pods per plant and the number of grains per pod were evaluated. Nitrogen fertilization in coverage significantly affected most of the growth, gas exchange and productivity variables, with the dose of 200 kg ha-1 being responsible for the highest values (p < 0.05). Chlorophyll fluorescence showed no significant differences among the nitrogen doses. The nitrogen doses influenced the growth, gas exchange and productivity of the common bean in the region of Brejo Paraibano. 


2018 ◽  
Vol 31 (3) ◽  
pp. 713-718 ◽  
Author(s):  
PATRÍCIA LÍGIA DANTAS DE MORAIS ◽  
NILDO DA SILVA DIAS ◽  
ANDRÉ MOREIRA DE OLIVEIRA ◽  
OSVALDO NOGUEIRA DE SOUSA NETO ◽  
JOSÉ DARCIO ABRANTES SARMENTO ◽  
...  

ABSTRACT Brackish waters represent great potential for profitable agricultural production; however, productive usage depends on the adoption of proper cultural practices as well as a culture tolerant of salinity, which can require some restrictions related to soil and crop production. Given the lack of information pertaining to hydroponic melon culture, the objective of this study was to investigate physiological changes promoted by the use of brackish water in the preparation of the nutrient solution for melon (Cucumis melo L., cv. AF 015) growth in coconut fiber substrate under greenhouse conditions in Mossoró-RN, a semiarid region of Brazil. The experimental design was completely randomized, with 12 treatments arranged in a 4 x 3 factorial scheme, with 4 salt concentration levels (1.1 - control, 2.5, 4.0 and 5.5 dS m-1) and 3 exposition times (vegetative growth: 10-30 days after transplanting, DAT; flowering: 31 to 50 DAT; and fruiting and ripening: 51-70 DAT, which are the assessment phases of physiological maturation). Increasing salt concentrations in the nutrient solution reduced photosynthetic efficiency, stomatal conductance and transpiration, but increased the intercellular CO2 concentration in melon plants. A salt concentration in the low to intermediate range (2.5 dS m-1) resulted in the best water use efficiency by melon crops.


2017 ◽  
Vol 239 ◽  
pp. 188-198 ◽  
Author(s):  
Khagendra R. Baral ◽  
Rodrigo Labouriau ◽  
Jørgen E. Olesen ◽  
Søren O. Petersen

2012 ◽  
Vol 550-553 ◽  
pp. 2365-2368
Author(s):  
Xiang Ming Chen

Using six kinds of concentration (ranged from 0.0 to 2.0mg.L-1) of flavone extract from C.cathayensis exocarp treats corn, soybean, wheat and mung bean seedlings, in order to study the photosynthetic rate, stomatal conductance, transpiration rate, intercellular CO2 on the seedling leaf. Results show that effects of flavone extract (0.1-0.5mg.L-1) increase content of the chlorophyll a, b and total chlorophyll, promote photosynthetic rate, stomatal conductance, transpiration rate, proper increase cell gap inside the CO2 concentration.0.1mg.L-1 treatment effect is the most obvious compare with the control, the total chlorophyll and photosynthetic rate increase by 20.9 % and 21% respectively; More than 0.5mg.L-1, the chlorophyll content, photosynthetic rate, stomatal conductance, transpiration rate decrease, the intercellular CO2 rapid increase. Research shows that, the appropriate concentration of flavone can increase the chlorophyll content in the leaf, promote stomatal opening, increase of intracellular CO2 supply, improve leaf photosynthesis efficiency.


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