Bargarh, India
Bargarh, India

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Panigrahi S.,Anchal College | Pradhan M.K.,Anchal College | Panda D.K.,Womens College | Joshi P.N.,Anchal College
Photosynthetica | Year: 2015

The photosynthetic responses to elevated CO2 concentration (EC) at ambient and ambient + 4°C temperature were assessed in the second leaf of rice (Oryza sativa L.) seedlings. The duration of different leaf developmental phases, as characterised by changes in photosynthetic pigment contents and photochemical potential, was protracted in the seedlings grown under EC. On the other hand, a temporal shift in the phases of development with an early onset of senescence was observed in the seedlings grown under EC at ambient + 4°C temperature. The contents of carotenoids, β-carotene, and xanthophyll cycle pigments revealed that EC down-regulated the protective mechanism of photosynthetic apparatus against oxidative damages, whereas this mechanism assumed higher significance under EC at ambient + 4°C temperature. We observed an enhancement in electron transport activity, photochemical potential, and net photosynthesis in spite of a loss in photostasis of photosynthesis under EC. On the other hand, the loss in photostasis of photosynthesis was exacerbated under EC at ambient + 4°C temperature due to the decline in electron transport activity, photochemical potential, and net photosynthesis. © 2016 The Institute of Experimental Botany


Joshi P.,Anchal College | Gartia S.,Anchal College | Gartia S.,Sambalpur University | Pradhan M.K.,Anchal College | And 3 more authors.
Acta Physiologiae Plantarum | Year: 2013

The photosynthetic responses of clusterbean (Cyamopsis tetraganoloba) cotyledons exposed to UV-A, UV-B or UV-A + UV-B radiation for 1 h daily until day 10 have been compared. The loss in the rate of O2 evolution and CO2 assimilation (P n) are incommensurate with each other in both UV-A and UV-B exposed samples indicating the occurrence of loss in photostasis of photosynthesis by these two radiation bands. The alteration in redox status of Q A further suggests about a loss in redox homeostasis in the photosynthetic electron transport chain. However, both photochemical efficiency of PS II and P n are well maintained in UV-A + UV-B exposed cotyledons in spite of reduction in water-use efficiency. The acclimatization of clusterbean cotyledon to UV-B radiation in the presence of UV-A has been attributed to accumulation of flavonoids, increase in stomatal conductance (g s) and reduction in functional size of PS II. © 2013 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.


PubMed | Anchal College
Type: Journal Article | Journal: Plant science : an international journal of experimental plant biology | Year: 2011

The effects of ultraviolet-B (UV-B: 280-320 nm) radiation on the photosynthetic pigments, primary photochemical reactions of thylakoids and the rate of carbon assimilation (P(n)) in the cotyledons of clusterbean (Cyamopsis tetragonoloba) seedlings have been examined. The radiation induces an imbalance between the energy absorbed through the photophysical process of photosystem (PS) II and the energy consumed for carbon assimilation. Decline in the primary photochemistry of PS II induced by UV-B in the background of relatively stable P(n), has been implicated in the creation of the energy imbalance(.) The radiation induced damage of PS II hinders the flow of electron from Q(A) to Q(B) resulting in a loss in the redox homeostasis between the Q(A) to Q(B) leading to an accumulation of Q(A)(-). The accumulation of Q(A)(-) generates an excitation pressure that diminishes the PS II-mediated O(2) evolution, maximal photochemical potential (F(v)/F(m)) and PS II quantum yield ((PS II)). While UV-B radiation inactivates the carotenoid-mediated protective mechanisms, the accumulation of flavonoids seems to have a small role in protecting the photosynthetic apparatus from UV-B onslaught. The failure of protective mechanisms makes PS II further vulnerable to the radiation and facilitates the accumulation of malondialdehyde (MDA) indicating the involvement of reactive oxygen species (ROS) metabolism in UV-B-induced damage of photosynthetic apparatus of clusterbean cotyledons.

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