Philippine Science Letters
vol. 6 | no. 1 | 2013
published online March 27, 2013


ARTICLE


Responses of rice (Oryza sativa line LX278) calli and seedlings to salinity treatment: Towards the development for salt tolerance


by Fredeslinda C. Evangelista1*, Rhodora R. Aldemita2, and Lilian B. Ungson3

1Department of Biology, University of the Philippines Manila, Padre Faura, Taft Avenue, Manila
2Philippine Rice Research Institute, Maligaya Munoz, Nueva Ecija
3Institute of Biology, University of the Philippines Diliman, Diliman, Quezon City





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Saline soil is a major problem that affects growth and yield of rice, the staple food in the Philippines; hence, there is a need to develop a local variety that can thrive under this condition for sustainable production. The goal of the study is to obtain baseline information regarding the responses of rice (Oryza sativa line LX278) calli and seedlings to salt. This is important prior to genetic transformation so that any improvement in growth performance, after transformation, could be attributed to the introduced salinity tolerance gene. Results showed that the mean fresh weight of LX278 rice calli exposed to various concentrations of NaCl, ranging from 50mM to 175mM, significantly decreased as the concentrations of NaCl increased compared to the control. Prolonged exposure of up to a month with 150 mM NaCl and 175mM NaCl restricted and inhibited, respectively, the growth of calli. Two-way ANOVA (analysis of variance) showed that the effect of the interaction of salt concentration and the duration of exposure on mean fresh weight of calli was highly significant. Meanwhile, LX278 rice seedlings in hydroponics, exposed to NaCl of EC=12 dSm-1, exhibited a salt sensitive response, relative to Pokkali, the tolerant control, and IR 29, the highly susceptible control, 16 days after initial salinization using the rating system based on visual symptoms of salt toxicity. Results of the present study agree with earlier findings that rice tolerates salinities of up to 30mM ~ 3dS m-1 and, beyond this, growth is compromised because of osmotic and ionic effects.


*Corresponding author
Email Address: fredes25@yahoo.com
Received: May 22, 2012
Revised: February 27, 2013
Accepted: February 27, 2013
Published: March 27, 2013
Editor-in-charge: Eduardo A. Padlan
Reviewers:
Juliana Janet M.Puzon
Gilda C. Rivero