Caryopsis

Schalen-frucbt, /. dry fruit, specif, caryopsis. -guss, m. chill casting, -gussform, /. chill, -gusskem, m. (Ftninding) chilled core, schalenhart, a. chilled. 

Comparison of the Overall Composition of Cell Wall Preparations. As can be seen from Table I, cell wall preparations showed a significant difference in their polymer composition. The endosperm cell walls resembled primary walls, since they were virtually free of lignin but rich in pectic substances. On the other hand, the cell wall preparations obtained from the caryopsis coat and the aleuron tissue were highly lignified, and their pectic content was very low. The germ cell wall showed a somewhat intermediate composition between these two types, probably reflecting the fact that it consists of several different tissues. 

Figure 1. Scanning electron micrograph of the cell wall preparations obtained from the different parts of rice grain (7). Caryopsis coat (upper left), aleuron layer (upper right), germ (lower left) and starchy endosperm (lower right). Bars in the picture indicate 5 /zm.

While the hemicelluloses obtained from the germ, aleuron, and caryopsis coat cell walls all showed a similar monosaccharide composition, this was not the case for the endosperm tissue. Thus, a major difference in the structure of hemicellulosic polysaccharides exists between the preparations obtained from the endosperm cell walls and those from the cell walls of the other parts of the grain, i.e., rice bran. (Rice bran consists of the caryopsis coat, aleuron layer and germ.) Comparison of the detailed structural features of the hemicellulosic polysaccharides of endosperm and bran cell walls will be discussed in the following sections. 

Heterodendrin, epi Epidermis Hexadecanoic acid methyl ester Lf 078 Hor V 9 P1HV164 Hordein B Caryopsis ... 

Narayanaswami, S. (1955). The structure and development of the caryopsis in some Indian millets. V Eleusine coracana. Gaertn. Paper Mich. Acad. Sci. Arts Lett. 40, 33-46. 

The caryopses of grasses and cereals are anatomically complex. The starch endosperm of the caryopsis is surrounded by the aleurone layer and pericarp, both of which can be partly or completely removed, along with the embryo, by the abrasive process known as pearling, which removes the bran. The flour obtained by milling a pearled grain consists of protein, starches, and a low proportion of endospermic hemicellulose and non-endospermic hemicellulose from the bran. 

Figure 1. Relative proportion of major rice caryopsis components (8).

Rice bran contains active enzymes (30). Germ and the outer layers of the caryopsis have higher enzyme activities. Some enzymes that are present include a-amylase, p-amylase, ascorbic acid oxidase, catalase, cytochrome oxidase, dehydrogenase, deoxyribonuclease, esterase, flavin oxidase, a and p-glycosidase, invertase, lecithi-nase, lipase, lipoxygenase, pectinase, peroxidase, phosphatase, phytase, proteinase, and succinate dehydrogenase. 

A Caryopsis or Grain is similar to an akene but differs from it by the pericarp being always fused with the seed coat. This fruit is... 

Pig. 101.—Achenial fruits. I, Akene of Pulsatilla eut vertieally, showing adherent feathery style (si), pericarp (p), testa (<), endosperm (e), hypocotyl (h) and cotyledons (col) the last two structures making up the embryo 2, caryopsis of wheat showing beard of hairs above and position of embryo of seed below 3, utricle of Chenopodium cut vertically to show calyx (c), pericarp (p) and seed (s) regions 4, nut of an oak consisting of a glans (g) and cupule (cm). 

Gross Structure of a Monocotyl Seed With fruit wall attached), Indian Corn.— The ripened seed of Indian Corn is surrounded by a thin, tough pericarp which is firmly adherent to and inseparable from the Spermoderm or seed coat. Because of this fact, while in reality a fruit called a caryopsis or grain, this structure is sometimes erroneously termed a seed. 

The rice grain consists of the huU and caryopsis or fruit (brown rice) as shown in Figure 28.1. The huU serves as a protective layer to prevent insect infestation as weU as rapid changes in moisture content dne to flnctnations in weather (humidity) conditions. The hnll constitntes approximately... 

Fig. 1. Indole-3-acetic acid levels in two different plant tissues, wheat caryopsis and bean seed. The data show the difference between levels of free lAA (F), free plus extractable conjugate (F+F) and total lAA (F). Values for free plus extractable conjugate were obtained by quantitative analysis of the aqueous acetone extract by GC-SIM-MS [7]. The values for total were obtained by direct tissue hydrolysis using 1 N NaOH at room temperature (wheat caryopsis [6]) or 7 N NaOH at 100°C (bean seed[4]). Hydrolysis of the wheat tissue with 7 N NaOH did not release additional lAA...

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