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We study the bifurcations of nonlinear waves for the generalized Drinfel’d-Sokolov systemut+(vm)x=0,vt+a(vn)xxx+buxv+cuvx=0calledD(m,n)system. We reveal some interesting bifurcation phenomena as follows. (1) ForD(2,1)system, the fractional solitary waves can be bifurcated from the trigonometric periodic waves and the elliptic periodic waves, and the kink waves can be bifurcated from the solitary waves and the singular waves. (2) ForD(1,2)system, the compactons can be bifurcated from the solitary waves, and the peakons can be bifurcated from the solitary waves and the singular cusp waves. (3) ForD(2,2)system, the solitary waves can be bifurcated from the smooth periodic waves and the singular periodic waves.

Salt stress is one of the major environmental threats to plant growth and development. However, the mechanisms of plants responding to salt stress are not fully understood. Through genetic screening, we identified and characterized a salt-sensitive mutant, ses5 (sensitive to salt 5), in Arabidopsis thaliana. Positional cloning revealed that the decreased salt-tolerance of ses5 was caused by a mutation in the transcription factor BP (BREVIPEDICELLUS). BP regulates various developmental processes in plants. However, the biological function of BP in abiotic stress-signaling and tolerance are still not clear. Compared with wild-type plants, the bp mutant exhibited a much shorter primary-root and lower survival rate under salt treatment, while the BP overexpressors were more tolerant. Further analysis showed that BP could directly bind to the promoter of XTH7 (xyloglucan endotransglucosylase/hydrolase 7) and activate its expression. Resembling the bp mutant, the disruption of XTH7 gave rise to salt sensitivity. These results uncovered novel roles of BP in positively modulating salt-stress tolerance, and illustrated a putative working mechanism.