To establish a feasible commercial cutting propagation system of mountain Rhododendron, the physiological changes during cutting propagation of Rhododendron scabrifolium Franch were investigated. The semi-hardwood stems of Rhododendron scabrifolium were collected and treated with KNAA and Hormodin. Contents of endogenous hormones indoleacetic acid (IAA), gibberellin (GA), zeatin riboside (ZR), and abscisic acid (ABA) were measured during the rooting period, the structural and number changes of starch grains and crystal in the middle scales were observed by scanning electron microscope (SEM). The results showed that the treatments of hormone significantly affected the growth rate of the root and its number. Higher IAA levels in cuttings induced formations of root better; GA levels showed a positive correlation with the cuttings' root formation, but ABA levels showed a negative correlation with the rooting rates; Cuttings needed ZR in early-stage of rooting process, but ZR levels decreased in late-stage of rooting process. At the early-stage of rooting, there is no starch grain and crystal in the cell chamber of xylem and myeloid cells. Along with adventitious root formation and differentiation, starch grains and crystals were also formed. Starch grains are mainly round and the type of crystal cluster-like calcium oxalate crystals.

Publication name	PAKISTAN JOURNAL OF BOTANY, 49 (6):2295-2299; DEC 2017
Author(s)	Li, Chaochan; Quan, Wenxuan; Chen, Xuejuan
Corresponding author(s)	QUAN Wenxuan  wenxuanq@gznu.edu.cn    Guizhou Normal Univ, Key Lab Mountainous Environm, Guiyang 550001, Guizhou, Peoples R China.
Author(s) from IGCAS	LI Chaochan

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