Abstract:

Aims Many xerophilous plants in the West Erdos region of Inner Mongolia share the same vegetative reproduction, fissurate growth, which is an important adaptation to drought environments. There are few correlated studies of fissurate growth.
Methods We studied the morphogenesis of fissurate growth of Reaumuria trigyna by sequential slicing and determined changes in the content of ABA, IAA, GA₃ and ZR using ELISA (Enzyme-linked immunosorbent assay).
Important findings Fissurate growth started from the base of stem. During certain phases of growth, the cambium layer of this part was asymmetric and the vessels of secondary xylem became smaller and fewer, while the amount of xylem fiber increased. The constriction formed here. Then the cells gradually disintegrated and the constriction became deeper. One constriction connected with the next one when they extended to the center of the fissurate part. The entire vascular bundle split into many single vascular bundles, and they separated from each other. There was abnormal structure in the fissurate part of R. trigyna, as xylem was divided into several rings by several layers of flat living cells. This could play a role in fissurate growth. IAA and ZT were more concentrated in the fissurate part of transitional plants than in roots, which probably regulated and promoted the growth and splitting of cells in the fissurate part.

Key words: fissurate growth, morphogenesis, phytohormone, Reaumuria trigyna