Photosynthetic carbon metabolism in potato leaves under changes in light intensity

Chikov, V. I.; Mikhailov, A. L.; Timofeeva, O. A.; Хамидуллина, Л. А.

doi:10.1134/s1021443716010040

Cited by 4 publications

(7 citation statements)

References 12 publications

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“…wild type decreased (by 16%), and in transformed plants increased (by 24%). A similar connection between the stomata and mesophyll chloroplasts was also shown in potato plants [29] and later in maize plants [30] under a rapid change in illumination. Thus, after a decrease in light stomata closed in the wild type tomato plants (as it usually happens in all plants), but became even more opened in the transformant Lin8-RNAi.…”

Section: The Regulatory Significance Of the Ratio Of Labeled Sucrose supporting

confidence: 76%

Photorespiration and Its Role in the Regulation of Photosynthesis and Plant Productivity

Chikov¹,

Akhtyamova²

2019

AJPS

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The results of long-term studies of photorespiration are summarized and the unsuccessful attempts to increase productivity by suppressing this process are shown. It has been shown that photorespiration and glycolate metabolism are involved in the regulation of the relationship between light processes in chloroplasts and the dark reactions of carbon dioxide assimilation. The studies were conducted on plants in vivo and were associated with the activity of the apoplastic invertase enzyme, affecting assimilate transport. In violation of donor-acceptor relations between photosynthetic and plant-assimilating organs (removal of part of organs-consumers of assimilates or leaves, increase in nitrate nutrition), the kinetics of inclusion of 14 C in glycolate was changed. This is due to the strengthening of the role of the transketolase mechanism of its formation. The study of genetically transformed plants, in which either an additional apoplastic invertase gene was introduced, or the existing gene was blocked and did not act, showed a different change in the ratio of 14 C-labeled sucrose/hexose and the transpiration response to reduced light. In this connection, the concept of the mechanism of photorespiration interaction with apoplastic invertase and stomatal apparatus of the leaf is proposed when the ratio of light and dark reactions of photosynthesis or assimilate transport is changed. The essence of the concept is that when the ratio of light and dark processes is disturbed, the concentration of organic acids changes first in mesophilic cells (mainly by photorespiration), and then in the extracellular space. It changes the activity of apoplastic invertase, which hydrolyzes sucrose and prevents it from being exported from the leaf. Hydrolysis of sucrose increases the osmoticity of the aquatic environment of the apoplast, which increases with movement to the stomata. The changed osmoticity of the environment around the stomatal guard cells changes the resistance of CO 2 diffusion into the leaf. This normalizes the ratio of light and dark processes in the sheet. Therefore, when illumination decreases, nitrate nutrition increases or difficulties arise with the use of photosynthesis products in acceptor organs, the ratio of 14 C-labeled sucrose/hexose decreases, and the stomata close. With increasing illumination, reverse events occur.

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Section: The Regulatory Significance Of the Ratio Of Labeled Sucrose supporting

confidence: 76%

Photorespiration and Its Role in the Regulation of Photosynthesis and Plant Productivity

Chikov¹,

Akhtyamova²

2019

AJPS

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“…Removal of a fragment of consuming organs of the cotton plant led to certain reduction in sucrose synthesis and intensification of generation of glycolate metabolism products and hexoses (Table 3) simultaneously sucrose and hexose radioactivity ratio decreased significantly. This data allowed suggesting the hypothesis of photosynthesis regulation [8], in which the increased stream of oxygen through the glycolate passage in case Previously it was noted that oxygen absorption by ETC is directly related to the regulation of reductive pentosephosphate pathway. This is proved by the experiments cited in the work [13].…”

Section: Cmentioning

confidence: 73%

“…The kinetics experiments with 14СО 2 in different concentrations of carbon dioxide (0.03% and 0.3%) showed significant differences in 14 С inclusion into glycolate and products of its metabolism [8]. The key differences are as follows:…”

Section: The Trend Of Photosynthetic Carbon Metabolism and Export Fun...mentioning

confidence: 98%

“…The suggested hypothesis of photosynthesis regulation presupposed the existence of another important role of photooxidative processes in the autotrophic cell activitysubstrate provision of the donor leaf protein and pigment biosynthesis as these processes are the quickest and the most direct way of organic acid and aminoacid production from primary products of photosynthesis. Relatively speaking, this point of view has long been known by photosynthesis researchers [17,18] but these statements were not related to admittance of necessity to convert glycolate cycle into the Calvin cycle. In case of inhibition of sugar efflux from mesofyll cells the reduction of glycolate metabolism products becomes practically impossible and these compounds must either be accumulated in the cell or recovered.…”

Section: Cmentioning

confidence: 99%

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The Role of Source-Sink Relations between Photosynthetic and Assimilate-Consuming Organs in Regulation of Plant Photosynthesis

Chikov¹

2017

ARTOAJ

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Cause and effect relationships between chloroplast photochemical reactions, CO 2 assimilation and oxygen photosynthetic metabolism, transport of sugars in the phloem, apoplastic invertase and leaf stomata activity have been established. Regulation of photosynthesis at the level of an assimilate donor leaf with the change of illumination or export of products of photosynthesis is effectuated as follows. In case of deficiency of products of chloroplast photochemical reactions there occurs incomplete regeneration of resulting primary CO 2 fixation products and rapid accumulation of oxygenated substances in cells, vacuoles and the apoplast of the leaf. Apoplastic fluid pH decrease activates the invertase and intensifies the sucrose splitting in the apoplast, which increases the osmolality of extracellular environment that is increased approaching the guard cells, where the main evaporation of water takes place. The osmolality of extracellular environment decreases the turgor of the guard cells and increases the resistance of СО 2 diffusion into the leaf.

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“…The main transport compound in most plant species is sucrose. As we presented earlier [9,10], the degree of sucrose hydrolysis in the leaf apoplast by invertase under changes in either light conditions or a "request" for sugar from organs accepting photosynthesis products, is the main regulatory mechanism for matching the intensity of CO2 fixation with the export of photoassimilates from leaves. Since non-leaf organs probably do not have such a mechanism for regulating photosynthesis and the export function of the photosynthetic apparatus, the ratio of 14C labeled sucrose/hexose was significantly lower than that of leaves, especially in the ear (Table 2).…”

Section: Methodsmentioning

confidence: 93%

Participation of stem and ear photosynthesis in formation of the crop and its quality in wheat

Chikov

Akhtyamova

2020

BIO Web Conf.

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Photosynthesis of various organs and their contribution to formation of ear caryopsis were measured using14CO2 labeled carbon in the phase of caryopsis formation of spring wheat plants (Moskovskaya-35). It turned out that inclusion of14C into amino acids is more than twice as high in photosynthesis of an ear. Among labeled low molecular weight compounds in caryopsis, during a short exposure (2 hours) after photosynthesis, the most of the labeled carbon in the14CO2 was found from the photoassimilates of the flag leaf (70.4%); from the ear (55.8%), and the least – from the stem under the flag (41.5%). The difference in inclusion of14C into the caryopsis’ total proteins was observed only with a short exposure of the photosynthesizing organ (2 hours). Water-soluble proteins, as products of photosynthesis of the flag leaf, were synthesized for the most in the caryopsis (flag – 73.9%; stem – 46.4% and ear – 44.8%), and in the synthesis of complex proteins, which are soluble in alkali and Triton X-100, most of14C was from the products of photosynthesis of non-leaf organs (10.5; 21.5; 28.4 and 4.3; 12.5; 13.4), respectively.

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Photosynthetic carbon metabolism in potato leaves under changes in light intensity

Cited by 4 publications

References 12 publications

Photorespiration and Its Role in the Regulation of Photosynthesis and Plant Productivity

Photorespiration and Its Role in the Regulation of Photosynthesis and Plant Productivity

The Role of Source-Sink Relations between Photosynthetic and Assimilate-Consuming Organs in Regulation of Plant Photosynthesis

Participation of stem and ear photosynthesis in formation of the crop and its quality in wheat

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