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The Associative Changes in Scutellum Nuclear Content and Morphology with Viability Loss of Naturally Aged and Accelerated Aging Wheat ( Triticum aestivum ) Seeds

View Article: PubMed Central - PubMed

ABSTRACT

Timely prediction of seed viability loss over long-term storage represents a challenge in management and conservation of ex situ plant genetic resources. However, little attention has been paid to study the process of seed deterioration and seed aging signals under storage. An attempt was made here to investigate morphological and molecular changes in the scutellum and aleurone sections of naturally or artificially aged wheat seeds using TUNEL assay and DAPI staining. Twelve wheat genotypes or samples exposed to natural ageing (NA) or accelerated ageing (AA) were assayed and these samples had germination rates ranging from 11 to 93%. The assayed samples showed substantial changes in scutellum, but not aleurone. The nuclei observed in the majority of the scutellum cells of the NA seed samples of lower germination rates were longer in size and less visible, while the scutellum cell morphology or arrangement remained unchanged. In contrast, longer AA treatments resulted in the loss of scutellum cell structure, collapse of cell layers, and disappearance of honey comb arrangements. These nuclei and structural changes were consistent with the DNA assessments of nuclear alternations for the selected wheat samples. Interestingly, the sample seed germination loss was found to be associated with the reductions in the scutellum nuclear content and with the increases in the scutellum nuclei length to width ratio. These findings are significant for understanding the process of wheat seed deterioration and are also useful for searching for sensitive seed aging signals for developing tools to monitor seed viability under storage.

No MeSH data available.


Agarose gels to illustrate DNA alterations in extracted DNAs of nine aging wheat samples with various germination rates.(A) and (B) Show an equal amount of extracted DNA per sample (A: 15 μg and B: 500 ng). The sample labels are listed in Table 1. Res B1 and S1 represent the DNA samples for AC Barrie and AC Superb digested by EcoRI enzyme for 3 h at 37°C, respectively. Green arrows indicate intact DNA; red arrows, DNA smearing in EcoRI digested DNA; green arrow head, DNA laddering; white arrow heads, DNA smearing; and white arrow, increased DNA smearing in AA wheat genotype.
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Figure 3: Agarose gels to illustrate DNA alterations in extracted DNAs of nine aging wheat samples with various germination rates.(A) and (B) Show an equal amount of extracted DNA per sample (A: 15 μg and B: 500 ng). The sample labels are listed in Table 1. Res B1 and S1 represent the DNA samples for AC Barrie and AC Superb digested by EcoRI enzyme for 3 h at 37°C, respectively. Green arrows indicate intact DNA; red arrows, DNA smearing in EcoRI digested DNA; green arrow head, DNA laddering; white arrow heads, DNA smearing; and white arrow, increased DNA smearing in AA wheat genotype.

Mentions: DNA quality was also assessed by loading 15 μg of total DNA onto 1.5% agarose gel (Figure 3A). The NA genotypes H1NA, H2NA, and FH exhibited more intact DNA and less DNA laddering (Figure 3A, green arrow) compared to other assayed genotypes. For the six genotypes (MINA, M2NA, L1NA, L2NA, L1AA, and L2AA), less intact DNA was observed with more DNA laddering in multiple of 180–200 bp or DNA smearing (Figure 3A, green and white arrow heads), respectively. The highest DNA smearing as visualized by intensity was observed in the genotype L2AA (Figure 3A, white arrow). We also employed two negative DNA controls (i.e., DNA extracted from the genotypes ‘AC Barrie’ and ‘AC Superb’) with digestion by EcoRI enzyme. Our controls (Figure 3A, Res B1 and Res S1) showed that the intensity of intact DNA band was considerably reduced and more DNA smearing was observed (Figure 3A, red arrows). This DNA smearing was more resembling to DNA smearing observed in L1AA and L2AA (Figure 3A, white arrow heads). However, DNA smearing was considerably higher in the negative controls compared to the AA genotypes. One interesting observation was the different position of intact bands for these assayed genotypes.


The Associative Changes in Scutellum Nuclear Content and Morphology with Viability Loss of Naturally Aged and Accelerated Aging Wheat ( Triticum aestivum ) Seeds
Agarose gels to illustrate DNA alterations in extracted DNAs of nine aging wheat samples with various germination rates.(A) and (B) Show an equal amount of extracted DNA per sample (A: 15 μg and B: 500 ng). The sample labels are listed in Table 1. Res B1 and S1 represent the DNA samples for AC Barrie and AC Superb digested by EcoRI enzyme for 3 h at 37°C, respectively. Green arrows indicate intact DNA; red arrows, DNA smearing in EcoRI digested DNA; green arrow head, DNA laddering; white arrow heads, DNA smearing; and white arrow, increased DNA smearing in AA wheat genotype.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037135&req=5

Figure 3: Agarose gels to illustrate DNA alterations in extracted DNAs of nine aging wheat samples with various germination rates.(A) and (B) Show an equal amount of extracted DNA per sample (A: 15 μg and B: 500 ng). The sample labels are listed in Table 1. Res B1 and S1 represent the DNA samples for AC Barrie and AC Superb digested by EcoRI enzyme for 3 h at 37°C, respectively. Green arrows indicate intact DNA; red arrows, DNA smearing in EcoRI digested DNA; green arrow head, DNA laddering; white arrow heads, DNA smearing; and white arrow, increased DNA smearing in AA wheat genotype.
Mentions: DNA quality was also assessed by loading 15 μg of total DNA onto 1.5% agarose gel (Figure 3A). The NA genotypes H1NA, H2NA, and FH exhibited more intact DNA and less DNA laddering (Figure 3A, green arrow) compared to other assayed genotypes. For the six genotypes (MINA, M2NA, L1NA, L2NA, L1AA, and L2AA), less intact DNA was observed with more DNA laddering in multiple of 180–200 bp or DNA smearing (Figure 3A, green and white arrow heads), respectively. The highest DNA smearing as visualized by intensity was observed in the genotype L2AA (Figure 3A, white arrow). We also employed two negative DNA controls (i.e., DNA extracted from the genotypes ‘AC Barrie’ and ‘AC Superb’) with digestion by EcoRI enzyme. Our controls (Figure 3A, Res B1 and Res S1) showed that the intensity of intact DNA band was considerably reduced and more DNA smearing was observed (Figure 3A, red arrows). This DNA smearing was more resembling to DNA smearing observed in L1AA and L2AA (Figure 3A, white arrow heads). However, DNA smearing was considerably higher in the negative controls compared to the AA genotypes. One interesting observation was the different position of intact bands for these assayed genotypes.

View Article: PubMed Central - PubMed

ABSTRACT

Timely prediction of seed viability loss over long-term storage represents a challenge in management and conservation of ex situ plant genetic resources. However, little attention has been paid to study the process of seed deterioration and seed aging signals under storage. An attempt was made here to investigate morphological and molecular changes in the scutellum and aleurone sections of naturally or artificially aged wheat seeds using TUNEL assay and DAPI staining. Twelve wheat genotypes or samples exposed to natural ageing (NA) or accelerated ageing (AA) were assayed and these samples had germination rates ranging from 11 to 93%. The assayed samples showed substantial changes in scutellum, but not aleurone. The nuclei observed in the majority of the scutellum cells of the NA seed samples of lower germination rates were longer in size and less visible, while the scutellum cell morphology or arrangement remained unchanged. In contrast, longer AA treatments resulted in the loss of scutellum cell structure, collapse of cell layers, and disappearance of honey comb arrangements. These nuclei and structural changes were consistent with the DNA assessments of nuclear alternations for the selected wheat samples. Interestingly, the sample seed germination loss was found to be associated with the reductions in the scutellum nuclear content and with the increases in the scutellum nuclei length to width ratio. These findings are significant for understanding the process of wheat seed deterioration and are also useful for searching for sensitive seed aging signals for developing tools to monitor seed viability under storage.

No MeSH data available.