TY - JOUR
T1 - 2,4-dichlorophenoxyacetic acid-induced leaf senescence in mung bean (Vigna radiata L. Wilczek) and senescence inhibition by co-treatment with silver nanoparticles
AU - Karuppanapandian, Thirupathi
AU - Wang, Hong Wei
AU - Prabakaran, Natarajan
AU - Jeyalakshmi, Kandhavelu
AU - Kwon, Mi
AU - Manoharan, Kumariah
AU - Kim, Wook
N1 - Funding Information:
The first author (TK) expresses his sincere thanks to Dr. J. Rajendhran, Department of Genetics, School of Biological Sciences, Madurai Kamaraj University, for helpful discussion and critical review of this manuscript. Statistical analysis support from Mrs. Sathiya Karuppanapandian, is thankfully acknowledged. This work was financially supported by grants from University Grants Commission under Centre for Excellence in Genomic Sciences (F.14-2/99-IUC/Univ. Excellence) and a Korea University Grant. We also wish to thank the anonymous reviewers for their comments and suggestions to improve our manuscript on various levels.
PY - 2011/2
Y1 - 2011/2
N2 - Leaf senescence induced by 2,4-dichlorophenoxyacetic acid (2,4-D) and senescence inhibition caused by supplementation with silver (Ag+) ions in the form of silver nitrate (AgNO3) or silver nanoparticles (AgNPs) were investigated in 8-day-old mung bean (Vigna radiata L. Wilczek) seedlings. Inhibition of root and shoot elongation were observed in mung bean seedlings treated with 500μM 2,4-D. Concomitantly, the activity of 1-aminocyclopropane-1-carboxylic acid synthase was significantly induced in leaf tissue. Leaf senescence induced by 2,4-D was closely associated with lipid peroxidation as well as increased levels of cytotoxic hydrogen peroxide (H2O2) and superoxide radicals (O2·-). Despite decreased catalase activity, the activities of peroxidase, superoxide dismutase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase were increased during 2,4-D-induced leaf senescence. Further, the levels of reduced ascorbate, oxidized ascorbate, and reduced glutathione were markedly decreased, whereas the level of oxidized glutathione increased. 2,4-D-induced leaf senescence in mung bean was accompanied by an increase in positive terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, nuclear DNA fragmentation, and the activity of a 15-kDa Ca2+-dependent DNase. Supplementation with 100μM AgNO3 or AgNPs inhibited 2,4-D-induced leaf senescence. The present results suggest that increased oxidative stress (O2·- and H2O2) led to senescence in mung bean leaves. Furthermore, significantly induced antioxidative enzymes are not sufficient to protect mung bean cells from 2,4-D-induced harmful ROS.
AB - Leaf senescence induced by 2,4-dichlorophenoxyacetic acid (2,4-D) and senescence inhibition caused by supplementation with silver (Ag+) ions in the form of silver nitrate (AgNO3) or silver nanoparticles (AgNPs) were investigated in 8-day-old mung bean (Vigna radiata L. Wilczek) seedlings. Inhibition of root and shoot elongation were observed in mung bean seedlings treated with 500μM 2,4-D. Concomitantly, the activity of 1-aminocyclopropane-1-carboxylic acid synthase was significantly induced in leaf tissue. Leaf senescence induced by 2,4-D was closely associated with lipid peroxidation as well as increased levels of cytotoxic hydrogen peroxide (H2O2) and superoxide radicals (O2·-). Despite decreased catalase activity, the activities of peroxidase, superoxide dismutase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase were increased during 2,4-D-induced leaf senescence. Further, the levels of reduced ascorbate, oxidized ascorbate, and reduced glutathione were markedly decreased, whereas the level of oxidized glutathione increased. 2,4-D-induced leaf senescence in mung bean was accompanied by an increase in positive terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, nuclear DNA fragmentation, and the activity of a 15-kDa Ca2+-dependent DNase. Supplementation with 100μM AgNO3 or AgNPs inhibited 2,4-D-induced leaf senescence. The present results suggest that increased oxidative stress (O2·- and H2O2) led to senescence in mung bean leaves. Furthermore, significantly induced antioxidative enzymes are not sufficient to protect mung bean cells from 2,4-D-induced harmful ROS.
KW - 2,4-Dichlorophenoxyacetic acid
KW - Ethylene
KW - Leaf senescence
KW - Mung bean
KW - Nuclear DNA fragmentation
KW - Silver nanoparticles
UR - http://www.scopus.com/inward/record.url?scp=78751700997&partnerID=8YFLogxK
U2 - 10.1016/j.plaphy.2010.11.007
DO - 10.1016/j.plaphy.2010.11.007
M3 - Article
C2 - 21144762
AN - SCOPUS:78751700997
SN - 0981-9428
VL - 49
SP - 168
EP - 177
JO - Plant Physiology and Biochemistry
JF - Plant Physiology and Biochemistry
IS - 2
ER -