Vacuoles of Mesophyll Cells as a Transient Reservoir for Assimilates

Vacuoles of Mesophyll Cells as a Transient Reservoir for Assimilates We studied the efflux of radioactive photosynthetic products from the central vacuole into the cytosol of protoplasts isolated from the mesophyll tissue of the sugar beet (Beta vulgaris L.) after their darkening and subsequent cessation of photosynthesis. Among the products accumulated in the vacuole were the 14C-labelled sugars malate and alanine, small amounts of citric, glutamic, and aspartic acids, and some other amino acids. During the initial 20–30 min of darkness, there was no substantial utilization of photoassimilates accumulated in the vacuole during the preceding light period. An efflux of assimilates occurred later, after 30–40 min of darkness. A decrease in the vacuolar 14C-sucrose occurred not only due to its exit into the cytosol but also because of its conversion into 14C-monosaccharides by the vacuolar invertase. In fact, this decrease in the sucrose content correlated well with the accumulation of monosaccharides. Immediately after photosynthesis ceased, the chloroplastic 14C-starch was utilized for the maintenance of cytoplasmic metabolism. After 30-min darkness, the content of starch in the chloroplasts decreased by several times. We believe that the vacuoles of sugar-beet mesophyll cells are transient reservoirs for assimilates and the products of their conversion (glucose and fructose), which can rapidly leave the vacuole to maintain homeostasis in the cytosol under varying environmental conditions. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Russian Journal of Plant Physiology Springer Journals

Vacuoles of Mesophyll Cells as a Transient Reservoir for Assimilates

Loading next page...
 
/lp/springer_journal/vacuoles-of-mesophyll-cells-as-a-transient-reservoir-for-assimilates-u6zmAiFj0N
Publisher
Kluwer Academic Publishers-Plenum Publishers
Copyright
Copyright © 2001 by MAIK “Nauka/Interperiodica”
Subject
Life Sciences; Plant Sciences
ISSN
1021-4437
eISSN
1608-3407
D.O.I.
10.1023/A:1009090312847
Publisher site
See Article on Publisher Site

Abstract

We studied the efflux of radioactive photosynthetic products from the central vacuole into the cytosol of protoplasts isolated from the mesophyll tissue of the sugar beet (Beta vulgaris L.) after their darkening and subsequent cessation of photosynthesis. Among the products accumulated in the vacuole were the 14C-labelled sugars malate and alanine, small amounts of citric, glutamic, and aspartic acids, and some other amino acids. During the initial 20–30 min of darkness, there was no substantial utilization of photoassimilates accumulated in the vacuole during the preceding light period. An efflux of assimilates occurred later, after 30–40 min of darkness. A decrease in the vacuolar 14C-sucrose occurred not only due to its exit into the cytosol but also because of its conversion into 14C-monosaccharides by the vacuolar invertase. In fact, this decrease in the sucrose content correlated well with the accumulation of monosaccharides. Immediately after photosynthesis ceased, the chloroplastic 14C-starch was utilized for the maintenance of cytoplasmic metabolism. After 30-min darkness, the content of starch in the chloroplasts decreased by several times. We believe that the vacuoles of sugar-beet mesophyll cells are transient reservoirs for assimilates and the products of their conversion (glucose and fructose), which can rapidly leave the vacuole to maintain homeostasis in the cytosol under varying environmental conditions.

Journal

Russian Journal of Plant PhysiologySpringer Journals

Published: Oct 10, 2004

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve Freelancer

DeepDyve Pro

Price
FREE
$49/month

$360/year
Save searches from Google Scholar, PubMed
Create lists to organize your research
Export lists, citations
Read DeepDyve articles
Abstract access only
Unlimited access to over
18 million full-text articles
Print
20 pages/month
PDF Discount
20% off