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Peroxidase activity in scutella of maize in association with anatomical changes during germination and grain storage.

Corona-Carrillo JI, Flores-Ponce M, Chávez-Nájera G, Díaz-Pontones DM - Springerplus (2014)

Bottom Line: Due to its composition, the FL prevents free diffusion and separates the embryo from the endosperm during germination.During storage at high relative humidity levels, which leads to fast or slow deterioration depending on the temperature, the activity of phenol peroxidase in the scutellum was associated with a loss of vigor and reduced germination capacity when compared with low temperature and low relative humidity conditions.Such deterioration is associated with alterations in autofluorescent emissions from endogenous compounds in the scutellum, indicating changes in the microenvironment or in the differential proportions of epidermal and FL components.

View Article: PubMed Central - PubMed

Affiliation: Department of Health Sciences, Division of Biological and Health Sciences, Laboratory for Tissue Biochemistry, Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico ; Posgrado en Biología Experimental, Division of Biological and Health Sciences, Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico.

ABSTRACT
The embryo of the maize grain (Zea mays L.) is separated from the starchy endosperm by a fibrous structure, which is called the fibrous layer (FL). Using histochemical staining, it was determined that the FL is composed of collapsed cellular layers that contain phenols, neutral lipids, and 1,3-β-glucan. Due to its composition, the FL prevents free diffusion and separates the embryo from the endosperm during germination. Twenty-four hours after imbibition, the scutellum epidermis initiated a series of asynchronous spatial modifications, including cell growth, the perforation of cell walls, increased peroxidase activity in the apoplastic space, and elevated levels of superoxide, phenols, and other components that interact with the fibrous layer, enabling its transformation in addition to the free flow between compartments. During storage at high relative humidity levels, which leads to fast or slow deterioration depending on the temperature, the activity of phenol peroxidase in the scutellum was associated with a loss of vigor and reduced germination capacity when compared with low temperature and low relative humidity conditions. Such deterioration is associated with alterations in autofluorescent emissions from endogenous compounds in the scutellum, indicating changes in the microenvironment or in the differential proportions of epidermal and FL components.

No MeSH data available.


Related in: MedlinePlus

Diffusion through fibrous layer. Dry grains were perforated through the embryo or endosperm, and the diffusion of aqueous or ethanol dyes was assessed; a, grain without stain; b-e, diffusion of I2-KI; f-j, diffusion of Brilliant Green; b, grain without perforation; c, grain perforated through both compartments; d and f, perforation through embryo; e and g, perforation through endosperm; h and i, grains perforated through endosperm, and h, treated with acetone, or i, treated with chloroform; j, grains perforated through embryo and treated with acetone:chloroform. Abbreviations: WS, without stain; WP, without perforation; FP, full perforation; Emb ChP, embryo chamber perforation; End ChP, endosperm chamber perforation.
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Fig2: Diffusion through fibrous layer. Dry grains were perforated through the embryo or endosperm, and the diffusion of aqueous or ethanol dyes was assessed; a, grain without stain; b-e, diffusion of I2-KI; f-j, diffusion of Brilliant Green; b, grain without perforation; c, grain perforated through both compartments; d and f, perforation through embryo; e and g, perforation through endosperm; h and i, grains perforated through endosperm, and h, treated with acetone, or i, treated with chloroform; j, grains perforated through embryo and treated with acetone:chloroform. Abbreviations: WS, without stain; WP, without perforation; FP, full perforation; Emb ChP, embryo chamber perforation; End ChP, endosperm chamber perforation.

Mentions: Under native conditions, a longitudinal cut of a dry grain of maize showed a yellow coloration in the pericarp, white in the endosperm, and pale yellow in the scutellum-embryonic axis (Figure 2a). This allowed for the visual contrast of regions during the assay and the examination of stain diffusion through the FL. In those grains where structural integrity was maintained, an external brown staining of the pericarp by I2-KI was evident without penetration of the dye, and the endosperm and embryo displayed their natural colors (Figure 2b). Perforation through the embryo or endosperm without causing damage to the FL enabled the diffusion of I2-KI or Brilliant Green, which stained either the embryo (Figure 2d, 2f) or the endosperm (Figure 2g) exclusively, depending on which of the two structures had been punctured. The diffusion speed of I2-KI in the endosperm was slower than that in the embryo, indicating a lower diffusion index. However, when the dye came into contact with the FL, it diffused preferentially, surrounding the FL through the endosperm without penetrating the embryo, indicating the existence of a barrier to diffusion between the two structures (Figure 2e). When the grains were perforated from the embryo through the FL, I2-KI diffused freely, staining the embryo and the endosperm (Figure 2c). Grains that were perforated from the endosperm and then treated with acetone (Figure 2h) or chloroform (Figure 2i) and those that were perforated from the embryonic chamber and treated with acetone:chloroform (Figure 2j) showed the free diffusion of Brilliant Green between the two organs, independent of the perforation site.Figure 2


Peroxidase activity in scutella of maize in association with anatomical changes during germination and grain storage.

Corona-Carrillo JI, Flores-Ponce M, Chávez-Nájera G, Díaz-Pontones DM - Springerplus (2014)

Diffusion through fibrous layer. Dry grains were perforated through the embryo or endosperm, and the diffusion of aqueous or ethanol dyes was assessed; a, grain without stain; b-e, diffusion of I2-KI; f-j, diffusion of Brilliant Green; b, grain without perforation; c, grain perforated through both compartments; d and f, perforation through embryo; e and g, perforation through endosperm; h and i, grains perforated through endosperm, and h, treated with acetone, or i, treated with chloroform; j, grains perforated through embryo and treated with acetone:chloroform. Abbreviations: WS, without stain; WP, without perforation; FP, full perforation; Emb ChP, embryo chamber perforation; End ChP, endosperm chamber perforation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128954&req=5

Fig2: Diffusion through fibrous layer. Dry grains were perforated through the embryo or endosperm, and the diffusion of aqueous or ethanol dyes was assessed; a, grain without stain; b-e, diffusion of I2-KI; f-j, diffusion of Brilliant Green; b, grain without perforation; c, grain perforated through both compartments; d and f, perforation through embryo; e and g, perforation through endosperm; h and i, grains perforated through endosperm, and h, treated with acetone, or i, treated with chloroform; j, grains perforated through embryo and treated with acetone:chloroform. Abbreviations: WS, without stain; WP, without perforation; FP, full perforation; Emb ChP, embryo chamber perforation; End ChP, endosperm chamber perforation.
Mentions: Under native conditions, a longitudinal cut of a dry grain of maize showed a yellow coloration in the pericarp, white in the endosperm, and pale yellow in the scutellum-embryonic axis (Figure 2a). This allowed for the visual contrast of regions during the assay and the examination of stain diffusion through the FL. In those grains where structural integrity was maintained, an external brown staining of the pericarp by I2-KI was evident without penetration of the dye, and the endosperm and embryo displayed their natural colors (Figure 2b). Perforation through the embryo or endosperm without causing damage to the FL enabled the diffusion of I2-KI or Brilliant Green, which stained either the embryo (Figure 2d, 2f) or the endosperm (Figure 2g) exclusively, depending on which of the two structures had been punctured. The diffusion speed of I2-KI in the endosperm was slower than that in the embryo, indicating a lower diffusion index. However, when the dye came into contact with the FL, it diffused preferentially, surrounding the FL through the endosperm without penetrating the embryo, indicating the existence of a barrier to diffusion between the two structures (Figure 2e). When the grains were perforated from the embryo through the FL, I2-KI diffused freely, staining the embryo and the endosperm (Figure 2c). Grains that were perforated from the endosperm and then treated with acetone (Figure 2h) or chloroform (Figure 2i) and those that were perforated from the embryonic chamber and treated with acetone:chloroform (Figure 2j) showed the free diffusion of Brilliant Green between the two organs, independent of the perforation site.Figure 2

Bottom Line: Due to its composition, the FL prevents free diffusion and separates the embryo from the endosperm during germination.During storage at high relative humidity levels, which leads to fast or slow deterioration depending on the temperature, the activity of phenol peroxidase in the scutellum was associated with a loss of vigor and reduced germination capacity when compared with low temperature and low relative humidity conditions.Such deterioration is associated with alterations in autofluorescent emissions from endogenous compounds in the scutellum, indicating changes in the microenvironment or in the differential proportions of epidermal and FL components.

View Article: PubMed Central - PubMed

Affiliation: Department of Health Sciences, Division of Biological and Health Sciences, Laboratory for Tissue Biochemistry, Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico ; Posgrado en Biología Experimental, Division of Biological and Health Sciences, Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico.

ABSTRACT
The embryo of the maize grain (Zea mays L.) is separated from the starchy endosperm by a fibrous structure, which is called the fibrous layer (FL). Using histochemical staining, it was determined that the FL is composed of collapsed cellular layers that contain phenols, neutral lipids, and 1,3-β-glucan. Due to its composition, the FL prevents free diffusion and separates the embryo from the endosperm during germination. Twenty-four hours after imbibition, the scutellum epidermis initiated a series of asynchronous spatial modifications, including cell growth, the perforation of cell walls, increased peroxidase activity in the apoplastic space, and elevated levels of superoxide, phenols, and other components that interact with the fibrous layer, enabling its transformation in addition to the free flow between compartments. During storage at high relative humidity levels, which leads to fast or slow deterioration depending on the temperature, the activity of phenol peroxidase in the scutellum was associated with a loss of vigor and reduced germination capacity when compared with low temperature and low relative humidity conditions. Such deterioration is associated with alterations in autofluorescent emissions from endogenous compounds in the scutellum, indicating changes in the microenvironment or in the differential proportions of epidermal and FL components.

No MeSH data available.


Related in: MedlinePlus