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Researcher Patil, J. R.
Advisor Desai, B. B.
Source KrishiKosh-Indian National Agricultural Research System
Content type Text
Educational Degree Master of Science (M.Sc.)
Publisher MPKV
File Format PDF
Language English
Subject Domain (in DDC) Technology ♦ Agriculture & related technologies
Subject Keyword Cotton ♦ Agricultural Biochemistry
Abstract A number of cytoplasmic male sterile (CMS) lines of cotton, their maintainers and restorers as well as hybrids were examined for carbon monoxide sensitivity to monitor genetic differences existing if any. The redox state of cytochrome a3 during in situ respiration of leaves of 21day old seedlings of cotton was assessed by measuring nitrite produced during aerobic assay of nitrate reductase. The carbon monoxide reacts with the reduced form of cytochrome a3 only, rendering the cytosolic NADH available for the reduction of nitrate to nitrite. Thus, the accumulation of nitrite under CO aerobic conditions gives information regarding the redox state of this terminal electron acceptor during steady state respiration. All the cotton cultivars tested in this study were insensitive to CO, indicating thereby that the cytochrome a3 was in a highly oxidised state during steady state respiration. There was a steady decline in the amount of nitrite formed as the ratio of CO:02 was decreased. The COrCU ratio of 40 or more was found to be necessary to inhibit the cytochrome £ oxidase in cotton cultivars. The pretreatment of the leaves of CO insensitive cotton cultivars with DNP (2,4-dinitrophenol) rendered them responsive to CO, indicating that cytochrome a, was reduced after absorption of the uncoupler either due to facilitation of electron flow from cytochrome a to a^ or inhibition of further metabolism of nitrite to ammonia, on account of ATP deficiency. The results with different incubation periods showed that rather than incubation time,the concentration of carbon monoxide is critical in the inhibition of cytochrome oxidase pathway of cotton. The increased response to carbon monoxide on pretreatment with water and salt stress could be possibly due to uncoupling of oxidative phosphorylation due to altered membrane structure.
Educational Use Research
Education Level UG and PG
Learning Resource Type Thesis
Publisher Place Maharashtra
Size (in Bytes) 3.96 MB