Intracellular Distribution of Proteins in Pea Cotyledons

Abstract

IntroductionAs a part of a study of organ and cellular senescence in plants, wve are delineating the structural and functional changes which occur in the cotyledons of germinating peas. As might have been expected from earlier reports that cotyledon cells are capable of performing oxidative phosphorylation, incorporation of labeled amino acids into protein (4) and de novo synthesis of certain enzymes (5), examination by electron microscopy showed the presence of all structures normally present in plant cells. In addition, a major fraction of the cell volume was found to be occupied with relatively large roughly spherical bodies, with no visible internal structure. The data presented here indicate that the reserve globulins are localized in these structures. These structures are easily isolated as a pellet following centrifugation of a pea cotyledon homogenate. The presence of similar protein bodies in peanut cotyledons has already been reported (1, 3). Material & MethodsThe peas (Pisunt sativurn, var. Early Alaska) were soaked in 1 % sodium hypochlorite for 30 minutes, rinsed in sterile distilled water, and transferred to moist sand in sterile Petri dishes. After one to three days' incubation at 25 C. the cotyledons were excised and examined microscopically and chemically. For Figure 5, 6, and 7 show the results of the chromatography of the various fractions OI1 DEAE colunmns and further support the conclusion that tile iiain component of the pellet and the proteiin bodlies is the globulin fraction and that the globulin fractioll is the major protein fraction of the pea cotyledon cells. It is interesting to note that the chromiiatograpllic separationl suggests the presence of four comiiponents in the globulin fraction while ultracentrifugal analyses indicate tw o major components (2).The supernatant fraction chromatographe(l in figure 8 -as from cotyledons of 3-daV old germlinating peas. The first pyrophosphatase peak may be an artifact. The three nmajor peaks always appear during cliromiiatography and the last pyrophosp)llatase peak increases greatly (luring tile third to sixtlh lays of germination. The sniall adenosine triphosphatase peak results froill the low activity of tile corresponding pyrophosphatase peak toward ATI at pH 7.1. The major adenosine triphosphatase peatk increases greatly duriing germiiiatioll an(l is the einzvnme stu(lied earlier by Young ail(l Varner (5). Tile proteins which becomle labeled in vivo fr-omii C14-labeled amiinio aci(ds (4) are in tile albulliin fraction and separate into five or six (liscrete peaks under the chromatographic con(litiolns use( hlere. B' a COIllbinlation of ill Xvixo iiltro(luctioil of lalbeledl aniiiio acids into proteills and the separation of these proteills by column cllromatographyv we liope to be able to identifv those enzymes which increase ill activity as a result of (le ilovo syntiesis and those whici illcrease as a result of solle kinld of activation. SummaryElectronmllicrograplis of pea cotyledon cells show that roughly-spherical bodies of about t...

Laboratory simulations of the transformation of peas as a result of heat treatment: changes of the physical and chemical properties

“…These cells are filled with a nucleus, cytoplasm, starch grains and protein bodies [2]. The greater proportion consists of starch grains with a 5 to 10 times larger diameter than the protein bodies [43]. This situation does not change until T oven =190 (C (Fig.…”

A Disc Electrophoretic Study of Globulin Proteins of Legume Seeds With Reference to Their Systematics

“…The separation of proteins by ion-exchange chromatography and molecular sieving has now found widespread use (Morris and Morris, 1963) but only a few reports are available where this method has been used in the analysis of protein of seeds (for example, see Varner and Schidlovsky, 1963). Chromatography on DEAE cellulose has been used by Grant and Lawrence (196=;) to separate the storage protein of peas into two main fractions, which they have identified as vicilin and legumin.…”

THE ULTRASTRUCTURE OF COTYLEDONARY TISSUE FROM GOSSYPIUM HIRSUTUM L. SEEDS

“…However, within 12 to 24 hours after the seeds had imbibed water, mitochondria in cells became visible, presumably arising de novo. Thus, it is obvious that changes occur quite rapidly in seeds after imbibition of water.Unfortunately, most electron microscope studies have been conducted on seeds which were allowed to imbibe water for various periods prior to fixation (16,18,25,28). Since rapid changes do occur in seeds upon imbibition of water, any technique involving imbibition of water, even for short periods, may not reflect their original condition.…”

“…Many ultrastructural studies have been directed to the terminal stages of seed development (7,8,12,17,27) or to the initial stages of seed germination (4,10,18,22,28), but relatively few studies have been conducted on the dry seed per se. Yet an understanding of the final changes on maturation and the first events of germination requires information on the mature, quiescent seed as a point of reference.…”