EFFECT OF SALINITY STRESS ON ANTIOXIDATIVE ENZYME ACTIVITIES IN TOMATO CULTURED IN VITRO

KANOKWAN SRINIENG1, TANATORN SAISAVOEY1, AND APHICHART KARNCHANATAT2*

Abstract: Under inappropriate environments, plants responses by changing their metabolisms to maintain homeostasis that acclimation abilities are different among species and varieties. Saline tolerance tomato is an alternative way to overcome saline soil condition of some areas in Thailand. This study aims to select one or some saline tolerance tomato varieties from mostly used commercial ones. Six tomato variety seeds (Pethlanna, Puangphaka, Seeda, Beefeater, Seeda chompoo and TE VF 1-3-4) were grown by tissue culture technique in MS medium and MS medium supplied with 0, 5, 10, 25 and 50 mM NaCl. The Puangphaka variety was selected since it could grow in all tests NaCl concentrations with best germination time compared to the others cultivar seeds and exhibited 80-90% growth compared to control group. The seedlings were further cultivated in the same medium for 7, 14 and 21 days before they were conducted to determine stem and root superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities as well as amount of chlorophyll. It was found

that the SOD, CAT and GPx exhibited increase and decrease trends nearly the same pattern in salinity responses but with different activity levels. Inhibition of nutrient uptake could also be seen from the results. The maximum activities were 5, 0.18, 0.08, 2 and 3 U/mg protein for stem SOD, stem CAT, root CAT, stem GPx and root GPx, respectively. Furthermore, the chlorophyll A and B levels were decrease slightly except for the 21 days plants which presented considerable decrease.

1Program in Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand

2Institute of Biotechnology and Genetic Engineering, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand

*Corresponding author e-mail: i_am_top@hotmail.com; Tel.: +662-218-8078; Fax: +662-253-3543;