naa a22 4500 510788246 CHVBK 20180411083310.0 cr unu---uuuuu 180411e20130101xx s 000 0 eng 10.1007/s12298-012-0142-6 doi (NATIONALLICENCE)springer-10.1007/s12298-012-0142-6 Natural leaf senescence: probed by chlorophyll fluorescence, CO2 photosynthetic rate and antioxidant enzyme activities during grain filling in different rice cultivars [Elektronische Daten] [Debabrata Panda, Ramani Sarkar] Natural leaf senescence was investigated in four rainfed lowland rice cultivars, FR 13A (tolerant to submergence), Sabita and Sarala (adapted to medium depth, 0-50cm stagnant flooding) and Dengi (conventional farmers' cultivar). Changes in the levels of pigment content, CO2 photosynthetic rate, photosystem II photochemistry and anti-oxidant enzyme activities of flag leaves during grain-filling stage were investigated. Chlorophyll content, photochemical efficiency of photosystem II and CO2 photosynthetic rate decreased significantly with the progress of grain-filling. Likely, the activities of antioxidant enzymes namely, superoxide dismutase, catalase, guaiacol peroxidase and ascorbate peroxidase decreased with progress of grain-filling. A substantial difference was observed among the four cultivars for the sustainability index (SI) of different photosynthetic parameters and antioxidant enzyme activities; SIs of those parameters, in general, were lower in low yielding cultivar FR 13A compared to the other three cultivars. Among the four cultivars Sabita gave maximum grain yield. Yet, SI of Pn was greater in Sarala and Dengi compared to the Sabita. SIs of electron transport (ETo/CS), maximal photochemical efficiency (Fv/Fm), area above Fo and Fm, catalase and ascorbate peroxidase were also greater in Sarala and Dengi. The data showed that among the different Chl a fluorescence parameters, PI could be used with greater accuracy to distinguish slow and fast senescence rice cultivars during grain-filling period. It was concluded that maintaining the vitality of rice plants during grain-filling gave guarantee to synthesize carbohydrate, however greater yield could be realized provided superior yield attributing parameters are present. Prof. H.S. Srivastava Foundation for Science and Society, 2012 Antioxidant enzymes nationallicence Flag leaf nationallicence Photosynthetic characteristics nationallicence Natural leaf senescence nationallicence Rice nationallicence AOX : Active oxygen species nationallicence APX : Ascorbate peroxidase nationallicence Area : Area above Fo and Fm nationallicence Chl : Chlorophyll nationallicence CAT : Catalase nationallicence CS : Cross-section nationallicence DAH : Days after heading nationallicence DIo/CS : Dissipation of heat per excited CS at Fo level nationallicence ETo/CS : Electron transport in a PS II per excited CS at Fo level nationallicence Fo : Minimal fluorescence of dark-adapted leaves nationallicence Fm : Maximal fluorescence of dark-adapted leaves nationallicence Fv : (Fm-Fo) Variable fluorescence nationallicence Fv/Fm : Maximum quantum yield of primary photochemistry of PS II nationallicence GPX : Guaiacol peroxidise nationallicence LSD : Least significant difference nationallicence PI : Performance index nationallicence Pn : CO2 photosynthetic rate nationallicence PS : Photosystem nationallicence RC/CSo : Number of reaction centres per excited CS at Fo level nationallicence SOD : Superoxide dismutase nationallicence Panda Debabrata Centre for Biodiversity and Conservation of Natural Resources, Central University of Orissa, 764020, Koraput, India aut Sarkar Ramani Division of Biochemistry, Plant Physiology and Environmental Sciences, Central Rice Research Institute, 753 006, Cuttack, Orissa, India aut Physiology and Molecular Biology of Plants Springer-Verlag 19/1(2013-01-01), 43-51 0971-5894 19:1<43 2013 19 12298 https://doi.org/10.1007/s12298-012-0142-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s12298-012-0142-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Panda Debabrata Centre for Biodiversity and Conservation of Natural Resources, Central University of Orissa, 764020, Koraput, India aut NATIONALLICENCE 700 1- Sarkar Ramani Division of Biochemistry, Plant Physiology and Environmental Sciences, Central Rice Research Institute, 753 006, Cuttack, Orissa, India aut NATIONALLICENCE 773 0- Physiology and Molecular Biology of Plants Springer-Verlag 19/1(2013-01-01), 43-51 0971-5894 19:1<43 2013 19 12298 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer