Tag Archives: photosynthesis.

241–255 D. Paulus, I. C. Zorzzi, D. Becker, G.A. Nava, A.L. de Paula and F.M. de Paula
Physiological indicators and yield of the Chinese cabbage cultivated at different soil water tensions
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Physiological indicators and yield of the Chinese cabbage cultivated at different soil water tensions

D. Paulus*, I. C. Zorzzi, D. Becker, G.A. Nava, A.L. de Paula and F.M. de Paula

Federal University of Technology - Paraná, Campus Dois Vizinhos, Faculty of Agronomia, Department of Agronomy, Street adress Estrada para Boa Esperança, km 04, postal code 157, Dois Vizinhos, Paraná, Brazil
*Correspondence: dalvapaulus@gmail.com

Abstract:

The development and yield of Chinese cabbage is influenced by soil moisture. The objective of this study was to evaluate the physiological indicators, development, and yield of Chinese cabbage (Brassica rapa subsp. pekinensis (Lour.) Rupr.) grown at different soil water tension ranges. Two experiments were conducted (2016–2017) in the Olericulture Sector of the Federal University of Technology of Paraná. Two cultivars of the Chinese cabbage, Eikoo and Kinjitsu, and four soil water tension ranges 13–17, 23–27, 33–37, and 43–47 kPa were studied. Eikoo presented higher relative chlorophyll index, photosynthesis, and fresh leaf mass than did Kinjitsu. Physiological indicators transpiration (5.8 mmol H2O m-2 s-1), photosynthesis (14.5 μmol CO2 m-2 s-1), stomatal conductance (0.31 mol H2O m-2 s-1), and WUE (39.4 kg m-3) were higher at 13–17 kPa soil water tension. Soil water tension ranges with high water restrictions reduced the fresh leaf mass of both cultivars. Fresh leaf mass decreased by 236.2 and 191.7 g plant-1 in the highest soil water tension range in 2016 and 2017, respectively, when compared with the fresh leaf mass at the 13–17 kPa tension range. The lowest water consumption was observed at the 13–17 kPa tension range. The year 2017 resulted in higher internal CO2 concentration, transpiration rate, fresh leaf mass, number of irrigations and water consumption compared to the year 2016. Thus, the irrigation regime for the most optimal Chinese cabbage cultivation should maintain the soil water tension range at 13–17 kPa.

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2097-2109 M. Militello, G. Sortino, G. Talluto and G. Gugliuzza
Split water application for a water supply reduction in Callistemon Citrinus pot plant
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Split water application for a water supply reduction in Callistemon Citrinus pot plant

M. Militello¹, G. Sortino²*, G. Talluto¹ and G. Gugliuzza¹

¹Council for Agricultural Research and Economics (CREA) – Research Centre for Plant Protection and Certification (CREA-DC), Bagheria (PA), Italy
²Department of Agriculture, Food and Forest Sciences (SAAF) – University of Palermo -Viale delle Scienze, ed.4, ingresso H, - IT90128 Palermo, Italy
*Correspondence: giuseppe.sortino@unipa.it

Abstract:

Irrigation management in Greenhouse Nursery Production (GNP) is based on empiric methods based on farmer personal experiences with over-irrigation results. The effects of irrigation volume and daily application were studied in a pot experiment carried out on rooted cuttings in a greenhouse The irrigation volume treatment was performed on Full and reduced Treatment. The treatment of water application was carried out with split supply and unsplit supply. The effects of the treatments were evaluated in terms of biomass accumulation and partitioning, leaf area, photosynthesis and stomatal response, chlorophyll content, and water productivity. Callistemon showed a good adaptation to the different treatments tested during the experiment. A positive relation was found between biomass accumulation and irrigation volume, moreover split water application increased plant Dry Weight.
Therefore, the highest biomass accumulation was registered in full irrigation volume in split application treatment, and this behavior was confirmed by the photosynthetic rate. No statistical differences were found, in terms of Relative Water Content (RWC), between the treatments. Stem water potential and stomatal conductance values suggest in Callistemon an anysohidric water stress response behavior.
Our results evidenced that, in Callistemon potted plants, an irrigation volume reduction is possible when a split application occurs during the daytime. A full irrigation volume amounts to 10.8 L per plant during the trial period of 90 days while the reduced volume amounts to 8.2 L per plant. Therefore, an increased water productivity can be obtained if the daily water requirement is split on two applications during the daytime. Our results highlighted a possible reduction in environmental impact of Callistemon greenhouse pot production, through the 25% reduction of the volume irrigation.

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134-146 I. Laktionov, O. Vovna, O. Cherevko and T. Kozlovskaya
Mathematical model for monitoring carbon dioxide concentration in industrial greenhouses
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Mathematical model for monitoring carbon dioxide concentration in industrial greenhouses

I. Laktionov¹*, O. Vovna¹, O. Cherevko² and T. Kozlovskaya³

¹State Higher Educational Institution 'Donetsk National Technical University', Ministry of Education and Science of Ukraine, Department of Electronic Engineering, Shibankova sq., 2, UA85300 Pokrovsk, Ukraine
²State Higher Educational Institution 'Priazovsky State Technical University', Ministry of Education and Science of Ukraine, Department of Automation and Computer Technologies, University str., 7, UA87500 Mariupol, Ukraine
³Kremenchuk Mykhailo Ostohradskyi National University, Department of biotechnologies and bioengineering, Pershotravneva str., 20, UA39600, Kremenchuk, Ukraine
*Correspondence: ivan.laktionov@donntu.edu.ua

Abstract:

Processes of monitoring and control the industrial greenhouses microclimate play a decisive role in growing crops under protected cultivation. Providing optimal climatic conditions in the production process of greenhouse agricultural products requires solving the scientific and applied problem of developing and researching a mathematical model for monitoring carbon dioxide concentration in industrial greenhouses. The proposed model takes into account the processes of diffusion and absorption of carbon dioxide, the geometric parameters of greenhouses, as well as the types and vegetation periods of crops grown under protected cultivation. Time characteristics of the carbon dioxide dynamics process under greenhouse conditions are estimated. Quantitative estimates of the diffusion transfer duration and carbon dioxide absorption are made for indeterminate varieties of tomatoes during planting and fruiting periods. Recommendations are given on the development of an adaptive methodology for the functioning and structural and algorithmic organization of computerized monitoring and management system for carbon dioxide top-dressing modes for greenhouse crops. The necessity of improving the proposed mathematical model and confirming the adequacy of its implementation efficiency on yield indicators of greenhouse crops is substantiated.

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445-454 K. Balina,, M. Balode, L. Muzikante and D. Blumberga
Impact of synthetic hormone 17α-ethinylestradiol on growth of microalgae Desmodesmus communis
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Impact of synthetic hormone 17α-ethinylestradiol on growth of microalgae Desmodesmus communis

K. Balina¹,*, M. Balode²⋅³, L. Muzikante² and D. Blumberga¹

¹Riga Technical University, Institute of Energy Systems and Environment, Azenes Str. 12/1, LV1048 Riga, Latvia; *Correspondence: karina.balina@rtu.lv
²Latvian Institute of Aquatic Ecology, Daugavgrivas 8, LV1048 Riga, Latvia
³University of Latvia, Faculty of Biology, Department of Hydrobiology, Kronvalda Boulevard 4, LV1010 Riga, Latvia

Abstract:

Microalgae has recently attracted much attention as a feedstock for biogas. Using wastewater as microalgae nutrition is a way how to produce algal biomass with low cost and minimum impact on environment. However, wastewater often is polluted with chemicals like pharmaceuticals which are among the commonly used chemicals in everyday life. The present study was aimed at the toxicity evaluation of a commonly used synthetic hormone, 17α-ethinylestradiol, using freshwater green algae Desmodesmus communis as a biotest organism. Parameters like healthy cell number and photosynthetic activity were determined and used to assess the toxicity. Lowest Observed Effect Concentration (LOEC) and 50% Effective Concentration (EC50) values were calculated for the parameters at different incubation times. It was found out that 17α-ethinylestradiol affects algal cell ability to grow, inhibits cell division and reduce photosynthetic processes in algal cells. Our research shows that inhibitory effect on growth of green algae D. communis start on concentration below 10 µg L-1 (4–8 µg L-1). Concentrations in the range of concentration 80–100 reduce growth by 50%, but concentrations 100–500 µg L-1 induce 100% reduction of growth rate and even calls initial algal cell destruction. Presence of EE2 in wastewater used for algal growth can affect productivity of a microalgae aquaculture.

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1202-1214 M. Golabadi, P. Golkar and B. Bahari
Remobilization assay of dry matter from different shoot organs under drought stress in wheat (Triticum aestivum L.)
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Remobilization assay of dry matter from different shoot organs under drought stress in wheat (Triticum aestivum L.)

M. Golabadi¹*, P. Golkar² and B. Bahari¹

¹Department of Agronomy and Plant Breeding, Collage of Agriculture, Isfahan (Khorasgan) Branch, Islamic Azad University, P.O. Box: 81595-158 Isfahan, Iran
²Institute of Biotechnology and Bioengineering, Isfahan University of Technology, P.O. Box: 84156-2781 Isfahan, Iran
*Correspondence: m.golabadi@khuisf.ac.ir

Abstract:

Remobilization of dry matter during the grain filling period in wheat is capable of helping the plant recover its grain yield under drought stress. In this study, the genotypic variation of different traits related to dry matter remobilization were measured in seven genotypes of wheat under the three different environment conditions of well-watered, drought stress at heading stage with application of extra nitrogen fertilizer (30%), and drought stress in Isfahan, Iran. Analysis of variance showed that the genotypes were different not only in their dry matter remobilization from the spike, the stem, the peduncle, and the leaf sheath but also in their current photosynthesis. Different environmental conditions were found to affect dry matter remobilization from the leaves and sheath, current photosynthesis, grain yield, and the relative contributions by the stem and the spike to grain yield. The highest values of spike and stem contribution to grain yield were obtained under drought stress while current photosynthesis was found to be the sole supplier for grain filling in normal conditions. Application of extra nitrogen fertilizer under drought stress was found to reduce the loss of grain yield in some genotypes as a result of enhanced vegetative growth, reserve accumulation, and dry matter remobilization to the grain.

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