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从“库”和“源”的角度出发,种子蛋白的含量既与蛋白质合成的强度和时间有关,同对又与蛋白质贮存的容量有关。蛋白体是种子蛋白贮存的主要场所之一。在开花后7～9 天,蛋白体开始在胚乳中形成,随着蛋白质的强烈合成,内质网(ER)充满核糖体,并开始膨大、断裂并形成小泡,形成的蛋白体常为多聚核糖体所包围,从多聚核糖体形成的蛋白质看来是由外向内进入蛋白体的。因而在蛋白体中常看到同心园的结构。成熟的蛋白体有明显的边界,直径为2.3～2.5μ。充满多聚核糖体的内质网可能在蛋白体的形成和贮藏蛋白的合成过程中起重要作用。关于蛋白质合成的强度,曾用~3H—亮氨酸和~3H—赖氨酸参入的方法研究了种子发育过程中蛋白质的合成,结果表明种子蛋白(~3H—亮氨酸参入)和赖氨酸丰富蛋白(~3H—赖氨酸参入)的合成在开花后7～9天达到高峰,大约2/3的蛋白质是在开花后15天以内的种子发育过程中合成的,因而种子发育的早期阶段是贮藏蛋白合成的关键时期。在种子发育过程中,含水量急剧下降是一个重要的生理特点。从开花后6～15天,含水量迅速下降,然后,保持在21～23%。但是当含水量迅速下降时,蛋白质的积累却不断增加并一直延续到开花后21天。用~3H—polv(U)饱和杂交测定的结果表明,polv(A)RNA水平在开花后7～11天迅速增加,然后很快下降,可能蛋白质和polv(A)RNA的合成对含水量变化的敏感程度是不同的,而在种子发育早期合成的polv(A)RNA只有部分是直接用于蛋白质的合成。
From the perspective of “pool” and “source”, the content of seed protein depends not only on the intensity and time of protein synthesis but also on the capacity of protein storage. Proteosomes are one of the main sites for seed protein storage. At 7-9 days after flowering, the proteome begins to form in the endosperm. As the protein is strongly synthesized, the endoplasmic reticulum (ER) is filled with ribosomes and begins to expand, rupture and form vesicles, often forming more proteosomes Surrounded by polyribosomes, the proteins formed by polysomes appear to enter the protein body from the outside to the inside. Thus often seen in the body of concentric park protein structure. Mature protein body has a clear border, the diameter of 2.3 ~ 2.5μ. Endoplasmic reticulum filled with polysomes may play an important role in the formation of protein bodies and in the synthesis of storage proteins. Regarding the intensity of protein synthesis, the synthesis of proteins during seed development has been studied using the incorporation of ~ 3H-leucine and ~ 3H-lysine. The results show that seed protein (~ 3H-leucine incorporation) and lysine The synthesis of acid-rich protein (~ 3H-lysine incorporation) peaked 7-9 days after flowering, and about two-thirds of the protein was synthesized during seed development within 15 days after flowering and thus the early stage of seed development Stages are a critical period in the storage of protein synthesis. In the process of seed development, a sharp decline in water content is an important physiological characteristics. From 6 to 15 days after flowering, water content decreased rapidly, and then kept at 21 ~ 23%. However, as water content decreased rapidly, protein accumulation continued to increase until 21 days after flowering. The results of saturation hybridization with ~ 3H-polv (U) showed that the polv (A) RNA level increased rapidly from 7 to 11 days after flowering and then decreased rapidly. It is possible that the synthesis of protein and polv (A) Are different in sensitivity, and only the part of the polv (A) RNA synthesized early in the seed development is directly used for protein synthesis.