נגישות
menu      
Advanced Search
Syntax
Search...
Volcani treasures
About
Terms of use
Manage
Community:
אסיף מאגר המחקר החקלאי
Powered by ClearMash Solutions Ltd -
Effect of potassium, magnesium, and calcium deficiencies on nitrogen constituents and chloroplast components in citrus leaves
Year:
1999
Authors :
Lavon, Ruth
;
.
Salomon, Raffi
;
.
Volume :
124
Co-Authors:
Lavon, R., Institute of Horticulture, Agricultural Research Organization, Volcani Center, Bet Dagan, 50250, Israel
Salomon, R., Institute of Plant Protection, Agricultural Research Organization, Volcani Center, Bet Dagan, 50250, Israel
Goldschmidt, E.E., Kennedy-Leigh Ctr. for Hort. Res., Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot, 76100, Israel
Facilitators :
From page:
158
To page:
162
(
Total pages:
5
)
Abstract:
The chlorotic appearance of mineral-deficient citrus leaves presumably reflects degradative changes in chloroplast components, most of which have nitrogen as a principal constituent. To examine this assumption the size of some major nitrogen pools, the SDS-PAGE pattern of soluble and chloroplast membranal proteins, and the activities of nitrate reductase and ribulose bisphosphate carboxylase (RuBPcase) were determined in leaves of rough-lemon (Citrus volkameriana Ten. and Pasq) plants grown hydroponically for 3 to 10 months under K, Mg, and Ca deficiencies. Plants grown under minerally deficient conditions produced less biomass. Leaves developing under K, Mg, and Ca-deficient conditions had significantly reduced concentrations of the respective elements. Chlorophyll levels of the chlorotic Mg and Ca-deficient leaves were lower than those of control leaves but chlorophyll a/b ratios were not markedly different. Calcium deficiency caused significant decreases in total nitrogen, nitrates, and the free amino acid pool. Proline which is the major component of the free amino acid pool decreased by 82.5%. Calcium-deficient leaves had significantly lower nitrate reductase and RuBPcase activities. The level of RuBPcase holoenzyme and its subunits were also reduced. Protein levels of K, Mg, and Ca-deficient leaves were not significantly altered. The SDS-PAGE patterns of soluble and chloroplast membranal proteins did not reveal major qualitative changes. In conclusion, the data do not demonstrate a general close link between chlorosis of minerally deficient citrus leaves and nitrogen metabolism. Calcium deficiency seems to specifically interfere with early stages of nitrogen assimilation and free amino acid accumulation but the metabolic integrity of the leaf is apparently maintained even under severe nutritional stress conditions.
Note:
Related Files :
Amino Acids
Citrus volkameriana
Leaf chlorosis
nitrate reductase
proline
RuBPcase
Show More
Related Content
More details
DOI :
Article number:
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
29742
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:49
Scientific Publication
Effect of potassium, magnesium, and calcium deficiencies on nitrogen constituents and chloroplast components in citrus leaves
124
Lavon, R., Institute of Horticulture, Agricultural Research Organization, Volcani Center, Bet Dagan, 50250, Israel
Salomon, R., Institute of Plant Protection, Agricultural Research Organization, Volcani Center, Bet Dagan, 50250, Israel
Goldschmidt, E.E., Kennedy-Leigh Ctr. for Hort. Res., Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot, 76100, Israel
Effect of potassium, magnesium, and calcium deficiencies on nitrogen constituents and chloroplast components in citrus leaves
The chlorotic appearance of mineral-deficient citrus leaves presumably reflects degradative changes in chloroplast components, most of which have nitrogen as a principal constituent. To examine this assumption the size of some major nitrogen pools, the SDS-PAGE pattern of soluble and chloroplast membranal proteins, and the activities of nitrate reductase and ribulose bisphosphate carboxylase (RuBPcase) were determined in leaves of rough-lemon (Citrus volkameriana Ten. and Pasq) plants grown hydroponically for 3 to 10 months under K, Mg, and Ca deficiencies. Plants grown under minerally deficient conditions produced less biomass. Leaves developing under K, Mg, and Ca-deficient conditions had significantly reduced concentrations of the respective elements. Chlorophyll levels of the chlorotic Mg and Ca-deficient leaves were lower than those of control leaves but chlorophyll a/b ratios were not markedly different. Calcium deficiency caused significant decreases in total nitrogen, nitrates, and the free amino acid pool. Proline which is the major component of the free amino acid pool decreased by 82.5%. Calcium-deficient leaves had significantly lower nitrate reductase and RuBPcase activities. The level of RuBPcase holoenzyme and its subunits were also reduced. Protein levels of K, Mg, and Ca-deficient leaves were not significantly altered. The SDS-PAGE patterns of soluble and chloroplast membranal proteins did not reveal major qualitative changes. In conclusion, the data do not demonstrate a general close link between chlorosis of minerally deficient citrus leaves and nitrogen metabolism. Calcium deficiency seems to specifically interfere with early stages of nitrogen assimilation and free amino acid accumulation but the metabolic integrity of the leaf is apparently maintained even under severe nutritional stress conditions.
Scientific Publication
You may also be interested in