In Vitro Development of Low Phosphorus-tolerant Lines in Rice (Oryza sativa L.)

摘要

Phosphorus (P) is the second most important macronutrient. P is present in the soil but due to its fixation and high sorbing capacity, it is least available to plants. In the present study, an attempt was made to develop P-tolerant somaclones of rice.For this study, four rice varieties, viz. PR113, Govind, Jaya and Kalanamak were selected and an in vitro culture experiment on MS media supplemented with different concentrations of P, i.e. 0, 0.15, 0.30, 0.47, 0.81, 1.1 and 1.2 mM (KH2PO4 as P source)was conducted. Sterilized mature embryos were used as explant for callus induction and after induction calli were transferred on MS media containing different concentrations of P. The best survived callus was selected in lowest P concentration in the media and was allowed for regeneration in MS media supplemented with 2.2 muM BAP in all the rice varieties under the study. After rooting on hormone-free MS media, plantlets were transferred to pots for hardening. Low P-tolerant callus was also used to study the effect of P stress on P content, proline content, superoxide dismutase activity and acid phosphatase activity. A decrease in P content with decrease in P concentration from 1.2 mM to 0 mM P and increase in incubation period from 21 to 28 days after P stress treatment was found. Increase in proline content, superoxide dismutase activity and acid phosphatase activity was observed with decrease in P concentration from 1.2 mM to 0 mM and increase in incubation period from 21 to 28 days after P stresstreatment.