Salinity Adaptation of Tobacco Salt-Tolerant Callus Variant
ZHOU Rong-Ren;YANG Xie-Rong;JI Yu-Ming;YU Shu-Wen Shanghai Institute of Plant Physiology, Academia Sinica, Shanghai 200032
By increasing the salt concentra-tion gradually, a cell line tolerant to2% NaC1 was established. The 2%NaC1-tolerant variant callus was sub-sultured through 52 passages in a modi-fied MS medium containing 2% NaC1,then transferred to a medium contain-ing 0.5%, 1.0%, 1.5%, or 2.0%NaC1 respectively with original type,its fresh wt, dry wt., relative growthrate and proline content were all supe-rior to original type (Table 1, Fig.2). The callus line possessed NaC1--tol-erance thoroughly and the NaC1--toler-ance was positively correlative withproline content. But when the 2% Na-C1--tolerant variant callus was subeul-tured though 29 passages in a mediumcontaining 2% NaC1, then transferredto NaC1--free for 11 and 20 pasaages, itdid not maintain the tolerance. Astable 2, 3 showed, they could onlytolerated NaC1 levels of 1.5% or1.0%. Self--pollinated progenies of regen-erated plant from the salt--tolerant vari-ant were obtained. The germinatingseeds (Fig. 3), seedlings (Fig. 4, 5)and adult plants of the progenies wereall not salt tolerant. The results showed that the in-creased tolerance to salt of tobacco cal-lus variant obtained as reported in thispaper was only a physiological adapta-tion.