naa a22 4500 510788289 CHVBK 20180411083310.0 cr unu---uuuuu 180411e20130101xx s 000 0 eng 10.1007/s12298-012-0143-5 doi (NATIONALLICENCE)springer-10.1007/s12298-012-0143-5 Effect of exogenous lead on growth and carbon metabolism of pea ( Pisum sativum L) seedlings [Elektronische Daten] [Rachana Devi, Nidhi Munjral, Anil Gupta, Narinder Kaur] The present study investigated the effect of exogenous lead (Pb) on seedling growth, carbohydrate composition and vital enzymes of sucrose metabolism, starch degradation, pentose phosphate pathway and glycolysis in pea seedlings. With 0.5mM Pb, reduction of about 50% in shoot and 80% in root lengths was observed. At 5 and 7days of seedling growth, cotyledons of Pb-stressed seedlings had about 25-50% lower α- and β-amylase activities resulting in their higher starch content. Low starch content in the cotyledons of control seedlings at days 1, 3, 5 and 7 may be due to higher investment of carbon for seedling growth. Seedlings exposed to Pb showed significant inhibition of about 30-50% in acid invertase activity in the growing tissues i.e. roots and shoots. Sucrose content increased by 10-20% in shoots with much larger increase in cotyledons at 5-7days of growth in Pb-stressed seedlings. In stressed seedlings, sucrose synthase (SS) and sucrose-6-phosphate synthase (SPS) enzymes were down regulated in the roots but SS activity was up regulated in the cotyledons leading to increased sucrose content. Exogenous Pb increased the activities of glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) in the cotyledons. Down regulation of G6PDH and up regulation of hexokinase (HXK) in the roots and shoots of stressed seedlings indicated that hexoses could be utilised preferably for glycolysis rather than pentose phosphate pathway in these tissues. Due to limited supply of sugars to growing tissues in the stressed seedlings, increased HXK may play a role in sugar sensing. Phosphoglucomutase (PGM) activity was maximum in the cotyledons and minimum in roots showing its importance in the conversion of glucose-1-phosphate into glucose-6-phosphate. Reduced seedling growth observed in the presence of exogenous Pb was mainly due to the decrease in the activities of amylases and invertases in the cotyledons and growing tissues respectively. Further biosynthetic capacity of the roots and shoots was down regulated in the pea seedlings due to reduced efficiency of pentose phosphate pathway under Pb toxicity. Prof. H.S. Srivastava Foundation for Science and Society, 2012 Pb toxicity nationallicence Pisum sativum nationallicence Carbon metabolism nationallicence Glycolysis nationallicence Pentose phosphate pathway nationallicence G6PDH : Glucose-6-phosphate dehydrogenase nationallicence 6PGDH : 6-phosphogluconate dehydrogenase nationallicence HXK : Hexokinase nationallicence LSD : Least significant difference nationallicence PGM : Phosphoglucomutase nationallicence SS : Sucrose synthase nationallicence SPS : Sucrose-6-phosphate synthase nationallicence Devi Rachana Department of Biochemistry, Punjab Agricultural University, 141 004, Ludhiana, India aut Munjral Nidhi Department of Biochemistry, Punjab Agricultural University, 141 004, Ludhiana, India aut Gupta Anil Department of Biochemistry, Punjab Agricultural University, 141 004, Ludhiana, India aut Kaur Narinder Department of Biochemistry, Punjab Agricultural University, 141 004, Ludhiana, India aut Physiology and Molecular Biology of Plants Springer-Verlag 19/1(2013-01-01), 81-89 0971-5894 19:1<81 2013 19 12298 https://doi.org/10.1007/s12298-012-0143-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s12298-012-0143-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Devi Rachana Department of Biochemistry, Punjab Agricultural University, 141 004, Ludhiana, India aut NATIONALLICENCE 700 1- Munjral Nidhi Department of Biochemistry, Punjab Agricultural University, 141 004, Ludhiana, India aut NATIONALLICENCE 700 1- Gupta Anil Department of Biochemistry, Punjab Agricultural University, 141 004, Ludhiana, India aut NATIONALLICENCE 700 1- Kaur Narinder Department of Biochemistry, Punjab Agricultural University, 141 004, Ludhiana, India aut NATIONALLICENCE 773 0- Physiology and Molecular Biology of Plants Springer-Verlag 19/1(2013-01-01), 81-89 0971-5894 19:1<81 2013 19 12298 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer