Chin J Plant Ecol ›› 2008, Vol. 32 ›› Issue (5): 1023-1030.DOI: 10.3773/j.issn.1005-264x.2008.05.007

• Original article • Previous Articles     Next Articles

EFFECTS OF CALCIUM NITRATE STRESS ON ASCORBATE-GLUTATHIONE CYCLE METABOLISM IN LEAVES OF HYDROPONICALLY-GROWN GRA- FTED EGGPLANT SEEDLINGS

WEI Guo-Ping, ZHU Yue-Lin(), LIU Zheng-Lu, ZHANG Gu-Wen, YANG Li-Fei   

  1. College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
  • Received:2007-11-05 Accepted:2008-02-21 Online:2008-11-05 Published:2008-09-30
  • Contact: ZHU Yue-Lin

Abstract:

Aims Oxidative stress is one of the responses of plants to salt stress, which causes the production of hydrogen peroxide (H2O2). Plants grafted on salt resistant rootstocks could improve their tolerance to salt stress because of the vigorous root system of rootstocks. However, little is known about the relationship between salt tolerance of grafted plants and the scavenging system of H2O2 under Ca(NO3)2 stress. Our objective was to investigate the mechanism and roles of ascorbate-glutathione metabolism system in salt tolerance of grafted eggplant under Ca(NO3)2 stress, including ascorbate pool, glutathione pool and the activities of antioxidant enzymes.

Methods We grafted cultivar ‘Suqi qie’ ( Solanum melongena) onto rootstock of ‘Torvum Vigor’ ( S. torvum), which is a salt tolerant cultivar introduced from Japan. We compared leaves of hydroponically-grown grafted and own-root eggplant seedlings grown under 80 mmol·L-1Ca(NO3)2 stress for changes of antioxidant enzyme activities, contents of antioxidants in ascorbate-glutathione cycle metabolism and content of H2O2.

Important findings Under Ca(NO3)2 stress, H2O2 content increased in leaves of eggplant seedlings and was significantly lower in leaves of grafted seedlings than own-root seedlings. Also, activities of antioxidant enzymes (APX, DHAR and GR), regenerating rates of AsA and GSH and redox statuses (ratios of AsA/DHA and GSH/GSSG) were significantly higher in leaves of grafted seedlings than own-root seedlings. We concluded that grafted eggplant seedlings had efficient metabolism of ascorbate-glutathione cycle, which scavenged the H2O2 rapidly to alleviate the oxidative damage of Ca(NO3)2 stress; therefore, grafted seedlings had a stronger tolerance to salt stress.

Key words: grafted eggplant, Ca(NO3)2 stress, ascorbate-glutathione cycle, hydroponically-grown