Plants seed structure

Related to amino acids is picolinic add (8), which is present at high concentrations in dormant tissues such as plant seeds and whose involvement in the quiescent state may involve iron chelation. Also mugineic acid (9) possesses strong Fe111 chelating properties. This amino acid derivative has been isolated from the roots of rice plants and has been found to have a strong stimulatory effect on Fe uptake. The crystal structure of a complex of Co111 shows that the anion of (9) can function as a hexadentate chelate.38... 

Marcone, M.F., Kakuda, Y., and Yada, R.Y. 1998. Salt-soluble seed globulins of dicotyleonous and monocotyledonous plants. II. Structural characterization. Food Chem. 63, 265-274. 

Fig. 2 a The detailed three-dimensional structure of crambin, a small (46-residue) plant seed protein (main chain in light gray, side chains in darker gray), b A cartoon view of the same protein. This view highlights the secondary structure decomposition of the structure with the two helices packing into each other along side a /1-sheet... 

When gas chromatography became established as an analytical technique, certain classes of metabolite proved particularly amenable to study. These were volatile oils (see monoterpenes), the constituents of leaf surface waxes and, in the form of their methyl esters, the fatty acid components of fixed oils and fats, particularly those occurring in seeds. Structural variation within each of these t)q)es of compound proved to be somewhat less pronounced than with many other groups of metabolites. Nevertheless, the classification of plant families on the basis of the chain length and degree of unsaturation of the predominant fatty acids was proposed (Smith, 1976). 

The two pyrrolizedine bases (53, R = H, and 53, R = OH) were isolated from the seeds of this plant. Their structures were ascertained largely by spectral methods 72). 

In recent years, new improved methods and techniques used for the isolation of compounds from plant materials, structure elucidation and determination of their biological activity have been developed, and studies in these fields are rapidly progressing. This article comprises a review on the structure elucidation and synthesis of new lignans from the seeds of these plants, research on which has been carried out by the author and co-workers. 

The major alkaloids of the seed of Funtumia elastica are irehdiamines A, B, C, and D. Four minor alkaloids, i.e. conamine (Id), conessine (Ic), tetramethyl-horrhimine (15a), and a new base, 20-epi-irehdiamine I (15b), have now been isolated from seeds of this plant. The structure of the latter base was assigned on the basis of its n.m.r. and mass spectra, and confirmed by its synthesis from progesterone by an unexceptional route. ... 

When petroleum pollutant leaked into the soil environment, it would damage the plant ecosystem structure and function of the microbial, soil, the plant growth, seed and fruit quality, etc P . The higher the petroleum concentration became the more rapidly the germination, growth and yield of crops declinedli l. 

In plant seeds, glycerolipids can be synthesized in two similar pathways, which are known as prokaryotic and eukaryotic systems. These pathways are localized in different subcellular compartments and are characterized by a similar two-stage enzymatic conversion of 5 n-glycero-3-phosphate (G3P) into phosphatidic acid (PA), but different further conversions of PA into structural, storage, or signaling lipids [65]. Despite the closeness of these two biosynthetic pathways, enzymes that catalyze acylation reactions are unique to each system. 

Relative molecular masses and subunit structures of some lectins from plant seeds... 

Finally, I introduce the naturally occurring protein surfactant originated from plants, called oleosin [75,76], In plant seeds, oils are stored in discrete organelles called oil bodies. Oil bodies are small spherical particles approximately 1 p,m in diameter. Notice in Fig. 14 the difference in size between plant oil bodies and mammalian lipoproteins (from approximately 10 nm to 80 nm in diameter) despite the similarity in structure. Each oil body has a core of triglycerides surrounded by a layer of phospholipids (Fig. 16) [76]. Oil bodies inside the cells of mature seeds or in isolated preparations are remarkably stable and do not aggregate or coalesce. This stability cannot be attained by only a layer of phospholipids. Seed oil bodies are stable because, in addition to the phospholipid layer, a layer of unique proteins, termed oleosin shields their surface. 

Many plants contain polyunsaturated fatty acid esters in their leaves or seeds, as do the foods derived from these plants. Such structures are prone to autoxidation that gives hydroperoxides leading to lower molecular... 

Tzen, J.T.C. and Huang, A.H.C. (1992) Surface structure and properties of plant seed oil bodies. J. Cell. Biol. 117, 327-335. 

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