Growth Ring Formation in the Starch Granules of Potato Tubers

Light-microscopic measurement of starch granule size is the preferred approach in most laboratories because it is simple, rapid and visual and because it can study both size and shape. However, potato juice consists of starch granules with very different sizes and precipitation/movement speeds, which causes differences when sampling the juice and taking the microscopic images. The previously described method is to scrape and transfer some juice from potatoes using a razor blade directly to a slide with some water for microscopic observation. In this study we used a tape-hole chamber on the microscopic slide to reduce the cover-slip-induced shifting of small and medium granules. We improved the starch measurement reproducibility by testing various juice sampling methods. The reproducibility between repeated experiments using 10 cultivars was increased from a correlation efficient r = 0.815 in the razor-blade-scraping method to r = 0.923 in a squeezing-juice method. The largest starch granule detected was 151 µm in length. Sampling methods (using a razor-blade or a garlic press) strongly influenced the granule length values measured from the same potato tuber. The results indicated that 1) The squeezing-juice approach is more reproducible, and 2) The average length of starch granules is one of the most reproducible scores but varies according to juice-sampling methods.

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Impactul parazitar: nematoda Ditylenchus destructor–tuberculi de cartofi infestaţi în primele faze de ditilenhoză

10.53937/9789975315975.48 ◽

2019 ◽

Author(s):

Maria Melnic ◽

◽

Dumitru Erhan ◽

Stefan Rusu ◽

Olesea Gliga ◽

...

Keyword(s):

Potato Tuber ◽

Dry Mass ◽

Physiological Changes ◽

Starch Granules ◽

Potato Tubers ◽

Cortical Tissue ◽

Pectic Substances ◽

Pectolytic Enzymes ◽

Potato Cell ◽

Ditylenchus Destructor

There are presented data about morpho-physiological changes, as well as physiologico biochemicals, which appear in the tissue of potato tubers infested with Ditylenchus destructor (phases 2, 3 ditylenchose). The obtained data confirms that, D. destructor in the nutrition process eliminates in parallel celulosolitic and pectolytic enzymes, which cause complete maceration of the pectocellulosic membranes of the infected potato cell, as well as the parenchymal cortical tissue in which predominantly cellulose and pectic substances , dominating being cellulose. The results of the biochemical analyzes revealed that, at this stage in the parasite tissue there is a diminishing of the dry mass quantity, and the increase of the quantity of water. It is important to mention that in the plasmalemma mechanically traumatized by the nematode stiletto, the main intracellular inclusions of the potato tuber - the starch granules - were kept without change. Subsequently, when plasmalemma is destroyed, the granules diffuse into the nematode suspension.

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Growth of14C-labelled starch granules in potato tubers as revealed by autoradiographs

PROTOPLASMA ◽

10.1007/bf01252442 ◽

1956 ◽

Vol 47 (1-2) ◽

pp. 156-163 ◽

Cited By ~ 44

Author(s):

N. P. Badenhuizen ◽

R. W. Dutton

Keyword(s):

Starch Granules ◽

Potato Tubers

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Oxidized Glutathione Promotes the Association of Proteins from Bean Seeds to Potato Starch

Journal of the Mexican Chemical Society ◽

10.29356/jmcs.v56i1.272 ◽

2017 ◽

Vol 56 (1) ◽

Author(s):

Paola Correa ◽

Lilia Bernal ◽

Patricia Coello ◽

Eleazar Martínez-Barajas

Keyword(s):

Water Absorption ◽

Potato Starch ◽

Seed Proteins ◽

Absorption Capacity ◽

Protein Release ◽

Water Absorption Capacity ◽

Oxidized Glutathione ◽

Starch Granules ◽

Bean Seed ◽

Potato Tubers

In this paper, we report the use of oxidized glutathione (GSSG) in promoting the association of bean seed proteins to starch granules purified from potato tubers. The resulting interaction was stable and only a small fraction of the bound proteins was released by washing with 5% glucose. Higher concentrations of glucose or other sugars (fructose, mannose and mannitol) failed to further increase protein release. Dithiothreitol (DTT) at concentrations up to 50 mM did not liberate the proteins associated to starch; however, applied after GSSG but before adding the proteins, it was very effective in preventing binding of proteins to starch. Lastly, starch modified by the bound proteins increased its water absorption capacity.

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