Document Details

Document Type : Article In Journal 
Document Title :
Photosynthetic efficiency and pigment contents in alfalfa (Medicago sativa) seedlings subjected to dark and chilling conditions
Photosynthetic efficiency and pigment contents in alfalfa (Medicago sativa) seedlings subjected to dark and chilling conditions
 
Subject : Botany 
Document Language : English 
Abstract : The functional activities of the photosynthetic apparatus of alfalfa (Medicago sativa L.) was investigated after 24 h of dark chilling treatment at 10°C and after 48 h recovery period at 25°C and 420 μmol m -2 S-1. Dark chilling limits photosynthesis due to chilling-associated oxidative damage, which enhanced the production of active oxygen species (AOS). Dark chilling treatment resulted in a significant reduction in the CO2 assimilation rate and decreased stomatal conductance. Stomatal limitation was largely responsible for the inhibition of CO2 assimilation generated by affections in the PSII functioning and also in the Calvin cycle. Photosynthetic parameters and chlorophyll fluorescence analyses showed the same degree of inhibition during the dark chilling period. However, chlorophyll fluorescence analysis showed an increase in the process of energy dissipation in the dark chilled leaves. In addition, leaves showed a significant decrease in chlorophyll a:b ratio and higher carotenoids-to-total chlorophyll ratio providing photoprotection. Under recovery, leaves recovered photosynthetic activity thus diminishing the potential power for AOS generation. 
ISSN : 1560-8530 
Journal Name : International Journal of Agriculture and Biology, Volume 10, Issue 3, 2008, Pages 306-310 
Volume : 10 
Issue Number : 3 
Publishing Year : 2008 AH
2008 AD 
Number Of Pages : 5 
Article Type : Article 
Added Date : Thursday, October 15, 2009 

Researchers

Researcher Name (Arabic)Researcher Name (English)Researcher TypeDr GradeEmail
سميره عمر سعيد بافيلSameera Omar BafeelResearcherDoctoratesbafil@kau.edu.sa
Ibrahim, M.MIbrahim, M.MResearcherDoctorate 

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