Characteristics of photosynthesis in maize leaves (С4 plants) upon changes in the level of illuminance and nitrate nutrition

Characteristics of photosynthesis in maize leaves (С4 plants) upon changes in the level of... We studied assimilation of 14СО2 and distribution of 14С among the products of 3-min-long photosynthesis of maize (Zea mays L.) leaves. The day before the experiment, half of the plants were fertilized with Ca(NO3)2 (1 g/L of water) at a rate of 6 L/m2. Five days before the experiment, some plants were shaded for adaptation (illuminance was reduced by 50%). On the day of the experiment (before the application of 14СО2), several shaded plants were exposed to direct sunlight for 3 min, and some plants grown at full light (light plants) were shaded for 3 min (illuminance of 50%). Unfertilized plants adapted for 5 days to shading showed photosynthesis of 75.9% of control level (full light). If light plants were transferred to shading for 3 min, their photosynthesis decreased to 42.1%. In plants shaded for 5 days and then transferred to full light, photosynthesis in 3 min was 96.3% of control level. At full light, fertilization with nitrate boosted photosynthesis to 132.6% as compared with control material, but photosynthesis decreased to 43.5 and 65.4% of control level in plants shaded for 5 days and those shaded for 3 min, respectively. At the same time, the plants shaded for 5 days and then exposed for 3 min to full light restored photosynthesis to almost control level (95.5%). Analysis of 14С distribution among the products of 3-min-long photosynthesis showed that, the same as in C3 plants, a decrease in illuminance (especially a sudden one) in maize reduced the ratio between labeled sucrose and hexoses and elevates incorporation of 14С into malate, which indicated that its consumption in bundle sheath cells was suppressed. A decrease in the ratio between labeled sucrose and hexoses became more pronounced under the influence of nitrates with this effect also occurring in transport products of photosynthesis (20 cm below 14С-providing leaf area). In plants fertilized with nitrates, radioactivity of sucrose (% of radioactivity of soluble compounds) decreased in all the types of illumination. When illuminance was suddenly reduced for 3 min, incorporation of 14С into sucrose was 21.5 against 51.2% in light plants, and radioactivity of aspartate and malate sharply rose to 13.7 and 26.1% (against 2.1 and 8.9% in control material). Incorporation of 14С into compounds of glycolate pathway was low (less than 2.5%), but it was somewhat greater in nitrate plants. We concluded that the same mechanism of interaction between stomatal apparatus of leaf epidermis, invertase of mesophyll apoplast, and photosynthetic metabolism of carbon with electron flux via electron transport chain in chloroplasts of bundle sheath cells, which governs the rate of photosynthesis and assimilate export from the leaf but is triggered by the extent of consumption in the bundle sheath cells of C4 acids produced in the mesophyll operates in C4 plants (the same as in C3 plants). http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Russian Journal of Plant Physiology Springer Journals

Characteristics of photosynthesis in maize leaves (С4 plants) upon changes in the level of illuminance and nitrate nutrition

Loading next page...
 
/lp/springer_journal/characteristics-of-photosynthesis-in-maize-leaves-4-plants-upon-W5dnVqzcK4
Publisher
Pleiades Publishing
Copyright
Copyright © 2016 by Pleiades Publishing, Ltd.
Subject
Life Sciences; Plant Physiology; Plant Sciences
ISSN
1021-4437
eISSN
1608-3407
D.O.I.
10.1134/S1021443716050034
Publisher site
See Article on Publisher Site

Abstract

We studied assimilation of 14СО2 and distribution of 14С among the products of 3-min-long photosynthesis of maize (Zea mays L.) leaves. The day before the experiment, half of the plants were fertilized with Ca(NO3)2 (1 g/L of water) at a rate of 6 L/m2. Five days before the experiment, some plants were shaded for adaptation (illuminance was reduced by 50%). On the day of the experiment (before the application of 14СО2), several shaded plants were exposed to direct sunlight for 3 min, and some plants grown at full light (light plants) were shaded for 3 min (illuminance of 50%). Unfertilized plants adapted for 5 days to shading showed photosynthesis of 75.9% of control level (full light). If light plants were transferred to shading for 3 min, their photosynthesis decreased to 42.1%. In plants shaded for 5 days and then transferred to full light, photosynthesis in 3 min was 96.3% of control level. At full light, fertilization with nitrate boosted photosynthesis to 132.6% as compared with control material, but photosynthesis decreased to 43.5 and 65.4% of control level in plants shaded for 5 days and those shaded for 3 min, respectively. At the same time, the plants shaded for 5 days and then exposed for 3 min to full light restored photosynthesis to almost control level (95.5%). Analysis of 14С distribution among the products of 3-min-long photosynthesis showed that, the same as in C3 plants, a decrease in illuminance (especially a sudden one) in maize reduced the ratio between labeled sucrose and hexoses and elevates incorporation of 14С into malate, which indicated that its consumption in bundle sheath cells was suppressed. A decrease in the ratio between labeled sucrose and hexoses became more pronounced under the influence of nitrates with this effect also occurring in transport products of photosynthesis (20 cm below 14С-providing leaf area). In plants fertilized with nitrates, radioactivity of sucrose (% of radioactivity of soluble compounds) decreased in all the types of illumination. When illuminance was suddenly reduced for 3 min, incorporation of 14С into sucrose was 21.5 against 51.2% in light plants, and radioactivity of aspartate and malate sharply rose to 13.7 and 26.1% (against 2.1 and 8.9% in control material). Incorporation of 14С into compounds of glycolate pathway was low (less than 2.5%), but it was somewhat greater in nitrate plants. We concluded that the same mechanism of interaction between stomatal apparatus of leaf epidermis, invertase of mesophyll apoplast, and photosynthetic metabolism of carbon with electron flux via electron transport chain in chloroplasts of bundle sheath cells, which governs the rate of photosynthesis and assimilate export from the leaf but is triggered by the extent of consumption in the bundle sheath cells of C4 acids produced in the mesophyll operates in C4 plants (the same as in C3 plants).

Journal

Russian Journal of Plant PhysiologySpringer Journals

Published: Aug 11, 2016

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