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Title: Carbohydrate metabolism in photosynthetic and nonphotosynthetic tissues of variegated leaves of Coleus blumei Benth

Abstract

Mature, variegated leaves of Coleus blumei Benth. contained stachyose and other raffinose series sugars in both green, photosynthetic and white, nonphotosynthetic tissues. However, unlike the green tissues, white tissues had no detectable level of galactinol synthase activity and a low level of sucrose phosphate synthase indicating that stachyose and possibly sucrose present in white tissues may have originated in green tissues. Uptake of exogenously supplied ({sup 14}C)stachyose or ({sup 14}C)sucrose into either tissue type showed conventional kinetic profiles indicating combined operation of liner first-order and saturable systems. Autoradiographs of white discs showed no detectable minor vein labeling with ({sup 14}C)stachyose, but some degree of vein labeling with ({sup 14}C)sucrose. Autoradiographs of green discs showed substantial vein loading with either sugar. In both tissues, p-chloromercuribenzenesulfonic acid had no effect on the linear component of sucrose or stachyose uptake but inhibited the saturable component. Both tissues contained high levels of invertase, sucrose synthase and {alpha}-galactosidase and extensively metabolized exogenously supplied {sup 14}C-sugars. In green tissues, label from exogenous sugars was recovered as raffinose-series sugars. In white tissues, exogenous sugars were hydrolyzed and converted to amino acids and organic acids. The results indicate that variegated Coleus leaves may be useful for studies onmore » both phloem loading and phloem unloading processes in stachyose-transporting species.« less

Authors:
 [1]
  1. Univ. of California, Riverside (USA)
Publication Date:
OSTI Identifier:
5957588
Resource Type:
Journal Article
Journal Name:
Plant Physiology; (USA)
Additional Journal Information:
Journal Volume: 93:2; Journal ID: ISSN 0032-0889
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; CARBOHYDRATES; METABOLISM; PLANTS; AUTORADIOGRAPHY; CARBON 14 COMPOUNDS; ENZYME ACTIVITY; LEAVES; OLIGOSACCHARIDES; PHOTOSYNTHESIS; TRACER TECHNIQUES; CHEMICAL REACTIONS; ISOTOPE APPLICATIONS; LABELLED COMPOUNDS; ORGANIC COMPOUNDS; PHOTOCHEMICAL REACTIONS; SACCHARIDES; SYNTHESIS; 551001* - Physiological Systems- Tracer Techniques

Citation Formats

Madore, M A. Carbohydrate metabolism in photosynthetic and nonphotosynthetic tissues of variegated leaves of Coleus blumei Benth. United States: N. p., 1990. Web. doi:10.1104/pp.93.2.617.
Madore, M A. Carbohydrate metabolism in photosynthetic and nonphotosynthetic tissues of variegated leaves of Coleus blumei Benth. United States. doi:10.1104/pp.93.2.617.
Madore, M A. Fri . "Carbohydrate metabolism in photosynthetic and nonphotosynthetic tissues of variegated leaves of Coleus blumei Benth". United States. doi:10.1104/pp.93.2.617.
@article{osti_5957588,
title = {Carbohydrate metabolism in photosynthetic and nonphotosynthetic tissues of variegated leaves of Coleus blumei Benth},
author = {Madore, M A},
abstractNote = {Mature, variegated leaves of Coleus blumei Benth. contained stachyose and other raffinose series sugars in both green, photosynthetic and white, nonphotosynthetic tissues. However, unlike the green tissues, white tissues had no detectable level of galactinol synthase activity and a low level of sucrose phosphate synthase indicating that stachyose and possibly sucrose present in white tissues may have originated in green tissues. Uptake of exogenously supplied ({sup 14}C)stachyose or ({sup 14}C)sucrose into either tissue type showed conventional kinetic profiles indicating combined operation of liner first-order and saturable systems. Autoradiographs of white discs showed no detectable minor vein labeling with ({sup 14}C)stachyose, but some degree of vein labeling with ({sup 14}C)sucrose. Autoradiographs of green discs showed substantial vein loading with either sugar. In both tissues, p-chloromercuribenzenesulfonic acid had no effect on the linear component of sucrose or stachyose uptake but inhibited the saturable component. Both tissues contained high levels of invertase, sucrose synthase and {alpha}-galactosidase and extensively metabolized exogenously supplied {sup 14}C-sugars. In green tissues, label from exogenous sugars was recovered as raffinose-series sugars. In white tissues, exogenous sugars were hydrolyzed and converted to amino acids and organic acids. The results indicate that variegated Coleus leaves may be useful for studies on both phloem loading and phloem unloading processes in stachyose-transporting species.},
doi = {10.1104/pp.93.2.617},
journal = {Plant Physiology; (USA)},
issn = {0032-0889},
number = ,
volume = 93:2,
place = {United States},
year = {1990},
month = {6}
}