Regulation of growth by light. Phytochrome localisation in a plant

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The Knowledge of where there is a phytochrome in a plant, of course, would help us to understand the mechanism of its action, and for reception of this information some methods have been used. The most detailed data about phytochrome distribution at level of light microscopy is received by us by means of a method immunotsito chemistry - with use of the antibodies synthesised in an organism of an animal after introduction to it in blood of alien fiber. Rabbits whom enter the phytochrome allocated from a vegetative fabric, synthesise antifitohromnyj an antibody. This substance after clearing specifically contacts phytochrome in cuts of a vegetative fabric. Presence here an antibody can be revealed thanks to linkage of its other end with enzyme peroksidazoj at which action on a substratum the insoluble painted product is formed. Phytochrome distribution in young runaways of the barley, found out by this method, is shown on fig. 11.15.

Later immunohimicheskie methods have been used for definition of subcellular localisation of phytochrome in runaways of an oats and the rice which has been grown up in the dark. To an irradiation phytochrome is usually distributed by red light in all cytoplasm and its membranes, and after a short irradiation comes to light only in certain sites of a cage. Probably, these sites - not kernels, neplastidy and not mitohondrii, and, probably, endoplazmatichesky! retikulum, scattered on all cytoplasm. Long influence of light leads to phytochrome occurrence as well v-kernels. In favour of such conclusions tell also experiments with the isolated subcellular fractions, however not all researchers agree with interpretation of the received results. data of physiological experiments allow to assume that phytochrome can be in a cage in many places according to its numerous functions. Apparently, it is localised inside etioplastov and mitohondry or in their external membranes as isolated organelly react to the influence by red and distant red light made after their allocation.

The Most detailed data has been received in a series simple, but graceful experiences with threadlike vodoroslju Mougeotia.

Each cage of this seaweed contains only one large hloroplast which turns so that its wide party is established in parallel top surface of a cage at an irradiation seaweed by red light and is perpendicular to it - at the subsequent irradiation distant red light. to gain such effect, there is no necessity to irradiate itself hloroplast: already at an irradiation a microbunch of any site of a cage the adjoining part hloroplasta moves only. At microbunch use ploskopoljarizovannogo light the polarisation plane makes appreciable impact on its efficiency. It means that phytochrome is focused in a cage not in the chaotic image; sounding by microbunches shows that hromoforu phytochrome certain orientation in plazmalemme is peculiar. Besides, as an irradiation the polarised red light most effectively when the polarisation plane is parallel cellular ' to a wall, and the subsequent influence by distant red light - when this plane is perpendicular to a wall, phytochrome, apparently, changes the orientation in a membrane on 90 ° at phototransformation.