African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6576

Full Length Research Paper

Responses of different rice (Oryza sativa L.) genotypes to salt stress and relation to carbohydrate metabolism and chlorophyll content

ZHANG Zhen-hua1,2,3,4, LIU Qiang1,2,3,4, SONG Hai-xing1,2,3,4, RONG Xiang-min1,2,3,4 and Abdelbagi M. Ismail5*
  1College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, 410128 China. 2Hunan Provincial Key Laboratory of Plant Nutrition in Common University, Changsha, 410128 China. 3Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Changsha, 410128 China. 4National Engineering Laboratory of High Efficiency Utilization of Soil and Fertilizer Resources, Changsha, 410128 China. 5Crops and Environment Sciences Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
Email: [email protected]

  •  Accepted: 10 November 2011
  •  Published: 31 January 2012

Abstract

 

The study aims to investigate the physiological mechanisms associated with salt tolerance of different rice genotypes; with emphasis on carbohydrate metabolism and chlorophyll concentration. Studies were conducted in a greenhouse and fields at the International Rice Research Institute (IRRI) during the dry season (November 2008 to March 2009) and the wet season (April 2009 to October 2010). Salt stress increased chlorophyll concentration in leaves of a tolerant (IR651) and a moderately tolerant (IR64) rice genotypes, but significantly decreased chlorophyll a/b ratio. Chlorophyll a concentration and chlorophyll a/bratio were higher in the leaves of IR651 than in the leaves of IR64 under salt stress, and this is probably one of the reasons for the higher tolerance of IR651 compared with IR64. Differences between genotypes in dry weight and leaf area were not significant under control condition; however, higher soluble sugars and starch concentrations in plant tissues were observed under control conditions than under salt stress. Conversion of soluble sugars into starch seems to be partially inhibited by salt stress as suggested by the higher concentrations of soluble sugars compared with starch under salt stress. Apparently, the salt tolerant genotype maintained higher soluble sugars, higher chlorophyll a and chlorophyll a/b ratio under salt stress, and these traits could have partially contributed to its salt tolerance.

 

Key words: Carbohydrate metabolism, chlorophyll concentration, rice, salt stress, salt tolerance.