Influence of clinorotation on some parameters of photosynthetic apparatus.

This study aimed to examine the electron transport rates in the thylakoids, isolated from leaves of pea plants grown under clinorotation and in vertical control, to measure the chlorophyll a/b (Chl a/b) ratio in such thylakoids and in photosystem I (PSI) particles isolated from them, to elucidate if there are any differences in changes of PS II activity in thylakoids and Chl a/b ratio in PS I particles under phosphorylation of polypeptides of thylakoid pigment-protein complexes.

Some characteristics of photosynthetic apparatus under conditions of spaceflight.

During colonization of space by humans, the bioregenerative life-support systems on board the space ships will require the plants with a highly efficient photosynthesis, a process producing food and O2 and removing CO2-Therefore, in recent years the scientists increasingly focus the their attention to study on photosynthetic apparatus of plants grown in space. Although the available data are quite scanty and, at times, controversial, it is Considered that the space grown plants differ from around control plants by growth and development, many structural and functional indices and metabolism. Data exist showing changes in the chlorophyll (Chl) content, structure and number of chloroplasts in the cell, swelling of thylakoids and decrease in the number and size of starch grains in the chloroplasts (for reviews, see Halstead and Dutcher, 1987; Kordyum, 1997).

Effect of clinostating on photosynthetic apparatus of pea plants.

The photosynthetic membrane composition and low temperature fluorescence spectra were analyzed for pea chloroplasts from control and clinostated plants. Clinorotation induces a decrease in the amount of the oligomeric form of the light-harvesting chlorophyll a/b complex (LHCII) and an increase of its monomeric form. Some changes in organization of photosystem 1 (PS1) complex were revealed as well.

Changes in lipid composition of Photosystem 1 particles from thylakoids phosphorylated under reductive or anaerobic conditions.

Changes in lipid composition of Photosystem 1 (PS 1) particles isolated from thylakoids phosphorylated under reductive or anaerobic conditions have been studied. Under reductive conditions, there was an increase in monogalactosyldiacylglycerol containing highly saturated fatty acids and phosphatidylglycerol containing transhexadecenoic fatty acid. Under anaerobic conditions, the amount of all lipid classes was increased.

Fluorescence studies on interaction between phospho-LHC II and subchloroplast Photosystem 1 preparations.

Chloroplast proteins were phosphorylated under two test conditions: 'white light' irradiance alone and 'white light' irradiance with the addition of glucose and glucose oxidase, used to produce an anaerobic medium. The interaction of phospho-LHC II with Photosystem 1 (PS 1) was studied for two types of PS I preparation. Changes in the chlorophyll a/b ratio and the ratio of 650 and 680 nm band intensities (E650/E680) in fluorescence excitation spectra were used in calculating the phospho-LHC II portion which became associated with PS 1.