THE OPTIMAL DOSAGE OF 60Co GAMMA IRRADIATION FOR OBTAINING SALT GLAND MUTANTS OF EXO-RECRETOHALOPHYTE LIMONIUM BICOLOR (BUNGE) O. KUNTZE

Abstract

Limonium bicolor (Bunge) O. Kuntze is a typical exo-recretohalophyte with multi-cellular salt glands. It is often used to improve saline-alkali soil. Seeds of L. bicolor were treated with different doses of 60Co gamma irradiation to determine the LD50 for 60Co gamma irradiation; the goal was to produce a relatively high number of mutants in salt gland development and salt secretion with a relatively low level of mortality. 60Co gamma irradiation did not greatly affect germination, but an increase in gamma dose prevented the development of true leaves and reduced the percentage of seedlings that emerged from soil. The LD50 for 60Co gamma irradiation was 120 Gy. Two mutants (few and many) were obtained under the LD50 using the screening methods — differential interference contrast microscope and leaf discs excretion model. Compared with the wild type, few and many had mutation in salt gland development, and many showed lower salt secretion rate per single salt gland than WT. These mutants would provide insight into the molecular mechanisms of salt gland development and salt secretion and into the development of salt-tolerant crop plants.