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Title:Biochemical and Physiological Aspects of Precocious Soybean Seed (Glycine Max (L.) Merr.); Maturation
Author(s):Rosenberg, Laurie Ann
Doctoral Committee Chair(s):Rinne, Robert W.,
Department / Program:Plant Biology
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, Plant Physiology
Abstract:As soybean seeds (Glycine max (L.) Merr.) develop, they undergo a change in seed moisture. When seeds are excised from the pod and planted, they do not exhibit seedling growth until a seed age of 63 days after flowering (DAF) when the percent seed moisture falls below 60%. In contrast, seed germination (radicle protrusion) can occur when seeds as young as 35 DAF (68-79% moisture) are excised, but this germination does not lead to comparable seedling growth frequencies unless seeds are first given a moisture loss to artificially reduce their moisture below 60%. A moisture loss treatment applied to 35 DAF seeds enables these seeds to precociously mature. Upon rehydration, these precociously matured seeds undergo the transition from germination (cell expansion) to seedling growth (cell division and expansion) and exhibit similar germination and seedling growth frequency patterns as naturally matured seeds (100%). During germination and seedling growth of precociously matured seeds, starch, soluble sugars, protein and oil levels followed patterns similar to naturally matured, germinating seeds and seedlings.
Experiments were conducted to compare changes in soybean seed metabolism, at the level of protein synthesis, during precocious and natural maturation. The pattern of protein synthesis in vivo was examined in 35 DAF seeds and naturally mature (65-73 DAF) seeds using ($\sp{35}$S) -methionine incorporation. Several novel polypeptides were synthesized de novo during precocious and natural maturation. Two of these polypeptides (31 kD and 128 kD) stained intensely with Coomassie Blue. The mRNAs corresponding to these "maturation" polypeptides accumulated during precocious maturation and were present in naturally matured seeds. Furthermore, several of these "maturation" polypeptides were synthesized during rehydration and germination of both precociously and naturally matured seeds until the onset of active protein reserve utilization during seedling growth.
Precocious maturation of immature soybean seeds enables the separation of biochemical and physiological changes associated specifically with maturation from those which are related to general seed development. Therefore, precocious maturation makes it possible to investigate the physiological events and biochemical control mechanisms during seed maturation which lead to seedling growth.
Issue Date:1987
Description:120 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987.
Other Identifier(s):(UMI)AAI8803182
Date Available in IDEALS:2015-05-14
Date Deposited:1987

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