scholarly journals Effect of Light Quality and Microbiological Inoculum on Geranium (Pelargonium zonale L.) Gas Exchange Parameters

2016 ◽  
Vol 44 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Anita Barbara SCHROETER-ZAKRZEWSKA ◽  
Klaudia BOROWIAK ◽  
Agnieszka WOLNA-MARUWKA

Geranium plants were cultivated in a growth chamber with different light quality and microorganism inoculation conditions. The long-term effect of irradiance quality (LED and fluorescent) as well as two types of microorganism treatments on photosynthetic activity parameters was examined. The maximum reached values of net photosynthesis rate (PN), stomatal conductance (gs), transpiration rate (E) and intercellular CO2 concentration (Ci) were afterwards measured in plants cultivated under six colours of light – white, white-blue, blue, red, red-blue and green – emitted by two types of lamp: LED and fluorescent. Two types of microorganism treatments were used: BAF1 created in the Department of General and Environmental Microbiology and the commonly used Effective Microorganisms (EM) biopreparation. A highest level of PN were found in plants after cultivation under white-blue light (both – fluorescent and LED) and treated by BAF1. The positive effect of EM was only noted in the case of plants cultivated under blue-red fluorescent light. Considering plants without microbial inoculation the highest levels were recorded in plants under red and blue light. The comparison of the effect of light quality revealed that in all colours a higher or similar level of net photosynthetic rate was noted in plants under LEDs. Mostly the higher photosynthetic activity was connected with higher stomatal opening as well as with higher transpiration rate, which is especially true for plants cultivated under red and blue LED light.

2020 ◽  
Vol 143 ◽  
pp. 02033
Author(s):  
Hancheng Guo ◽  
Zhiguo Fang

Effect of light quality, including red light, blue light, white light, red and blue mixing light with 8:1, 8:2 and 8:3, on the growth characteristics and metabolite accumulation of chlorella pyrenoidosa was conducted based on light emitting diode (LED). Results showed that chlorella pyrenoidosa grew best under blue light, and the optical density, specific growth rate and biomass of chlorella pyrenoidosa was about 2.4, 0.10 d-1 and 6.4 g·L-1, respectively, while the optical density of chlorella pyrenoidosa was between 1.0 and 1.7, specific growth rate was between 0.06-0.10 d-1 and biomass was between 2.7 and 3.8 g·L-1 under other light quality after 30 days of cultivation. The optical density, specific growth rate and biomass of chlorella pyrenoidosa was approximately 2.05 times, 1.33 times and 2.06 times under blue light than red light, respectively. Moreover, Red and blue mixing light was conducive to the synthesis of chlorophyll a and carotenoids of chlorella pyrenoidosa, and blue light could promote the synthesis of chlorophyll b. Chlorophyll a and carotenoids content of chlorella pyrenoidosa was 13.5 mg·g-1and 5.8 mg·g-1 respectively under red and blue mixing light with 8:1, while it was 8.4 mg·g-1 and 3.6 mg·g-1 respectively under blue light. Red and blue mixing light was more conducive to protein and total lipid content per dry cell of chlorella pyrenoidosa. Protein and total lipid content was 489.3 mg·g-1 and 311.2 mg·g-1 under red and blue mixing light with 8:3, while it was 400.9 mg·g-1 and 231.9 mg·g-1 respectively under blue light.


1962 ◽  
Vol 40 (12) ◽  
pp. 1619-1630 ◽  
Author(s):  
A. H. W. Hauschild ◽  
C. D. Nelson ◽  
G. Krotkov

The effect of light quality on the products of photosynthesis has been studied in two species of green algae, Chlorella pyrenoidosa and Scenedesmus acuminatus, the blue-green alga Microcystis aeruginosa, and the photosynthetic bacterium Chromatium sp.The test organism was placed in C14-bicarbonate and illuminated at saturation intensities of red, red plus supplementary blue, blue alone, or white light. After 30 minutes, the distribution of C14 among the products of photosynthesis was determined using the techniques of paper chromatography and autoradiography.At a high concentration of cells of Chlorella pyrenoidosa, blue light caused an increase in C14 in aspartic, glutamic, fumaric, and malic acids and a decrease in sucrose and phosphate esters, although the rate of photosynthesis remained the same. At a low concentration of cells, similar changes were found, and these were accompanied by an increase in the rate of photosynthesis.Similar changes in the distribution of C14 due to blue light were found also in Scenedesmus. In Microcystis, a substantial increase in C14 due to blue light was found only in glutamic acid. The rate of photosynthesis remained the same in both organisms.The results indicate that the nature of the effect of blue light is the same in all of these organisms and in Chlorella vulgaris which was studied previously.Pretreatment in darkness is a prerequisite for a pronounced effect of blue light on the products as well as the rate of photosynthesis.No effect of light quality was found in Chromatium.


1962 ◽  
Vol 40 (1) ◽  
pp. 179-189 ◽  
Author(s):  
A. H. W. Hauschild ◽  
C. D. Nelson ◽  
G. Krotkov

Suspensions of Chlorella vulgaris, grown in synchronous culture, were pretreated in darkness for 45 to 225 minutes and illuminated in the presence of C14-bicarbonate with red, with red plus 4% of blue, and with blue light alone. The light intensities were so adjusted that the rate of photosynthesis (fixation of C14) was the same under the different conditions of illumination. The distribution of C14 among the various compounds of the ethanol-soluble fraction was obtained using paper chromatography and autoradiography.After 5 minutes of photosynthesis, the incorporation of C14 into aspartic acid was higher in the presence of red with supplementary blue light than in red light alone. At the same time the total radioactivity in glycine plus serine and in glycolic acid decreased. After 30 minutes of photosynthesis, blue light supplementary to red and blue light alone increased the total incorporation of C14 into the amino acid plus organic acid fraction as compared with incorporation in red light. This was due mainly to an increase in the radioactivity of aspartic and glutamic acids, while at the same time the radioactivity in glycine and glycolic acid was reduced.The duration of dark pretreatment was an important factor in the 30-minute experiments. The effect of increased dark pretreatment was to lower the incorporation of C14 into aspartic and glutamic acids when photosynthesis was carried out in red light, but the incorporation of C14 into these acids was increased in the presence of supplementary blue light.It is concluded that the distribution of carbon among the products of photosynthesis is affected by the quality of light.


Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1000
Author(s):  
Jolanta Bojarszczuk

A field experiment was carried out in 2017–2019 as a split-plot design with four replicates at the Agricultural Experimental Station in Grabów, Poland. The aim of the study was to compare the gas exchange parameters of the pea depending on the use of different soil tillage systems. Physiological plant parameters as: net photosynthetic rate (PN), transpiration rate (E), stomatal conductance (gs), intercellular CO2 concentration (Ci) and relative chlorophyll content were measured in three developmental stages. The study have showed that all the measured parameters were affected by the tillage system of the soil. Net photosynthetic rate and transpiration rate were significantly lower in the treatments, where simplified-tillage was applied. Pea grown in the plough tillage (CT) showed a generally higher rate of net photosynthesis and transpiration rate compared to that of peas grown in the reduced tillage and no-tillage systems, but this was dependent on the plant development stage and the weather conditions prevailing in a given year. The highest intercellular CO2 concentration (Ci) under different cultivation methods were found in the no-tillage system, regardless of the developmental stage of legumes. The values of determination coefficients showed a positive relationship between the photosynthetic rate and seed yield of the peas tested in all the years of the research. The study also showed that a significantly higher SPAD index was found in the CT tillage system, irrespectively on the developmental stage.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Gilor Kelly ◽  
Danja Brandsma ◽  
Aiman Egbaria ◽  
Ofer Stein ◽  
Adi Doron-Faigenboim ◽  
...  

AbstractThe hypocotyls of germinating seedlings elongate in a search for light to enable autotrophic sugar production. Upon exposure to light, photoreceptors that are activated by blue and red light halt elongation by preventing the degradation of the hypocotyl-elongation inhibitor HY5 and by inhibiting the activity of the elongation-promoting transcription factors PIFs. The question of how sugar affects hypocotyl elongation and which cell types stimulate and stop that elongation remains unresolved. We found that overexpression of a sugar sensor, Arabidopsis hexokinase 1 (HXK1), in guard cells promotes hypocotyl elongation under white and blue light through PIF4. Furthermore, expression of PIF4 in guard cells is sufficient to promote hypocotyl elongation in the light, while expression of HY5 in guard cells is sufficient to inhibit the elongation of the hy5 mutant and the elongation stimulated by HXK1. HY5 exits the guard cells and inhibits hypocotyl elongation, but is degraded in the dark. We also show that the inhibition of hypocotyl elongation by guard cells’ HY5 involves auto-activation of HY5 expression in other tissues. It appears that guard cells are capable of coordinating hypocotyl elongation and that sugar and HXK1 have the opposite effect of light on hypocotyl elongation, converging at PIF4.


2018 ◽  
Vol 10 (1) ◽  
pp. 34-39
Author(s):  
Ting Wang ◽  
Xiang-rong Tian ◽  
Xiao-yu Wu ◽  
Zhun Luo ◽  
Gui Li ◽  
...  

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