Effects of Root Pruning on Adventitious Root Formation, Enzyme Activities, and Hormone Levels in Paeonia suffruticosa ‘Fengdanbai’ Seedlings

Abstract

Root pruning during early root development can optimize the root structure of woody plants. To determine the effects of root pruning on tree peony (Paeonia suffruticosa), seedlings of the tree peony cultivar 'Fengdanbai' were subjected to varying degrees or different styles of root pruning. Various indexes were analyzed, including the anatomical structure of the root, root vitality, the activity levels of antioxidant enzymes, and the contents of endogenous hormones and their ratios. Comprehensive morphological observation showed that pruning freshly germinated roots that are 3 cm long by 1/3 (i.e., removing 1 cm) yielded the greatest rooting rate (90%), lateral root initiation (2.34 per seedling), and subsequent growth. Analysis of physiological and biochemical indicators during the critical rooting period (3-5 days after root pruning) showed that the levels of superoxide dismutase and abscisic acid (ABA) were decreased, while the oxidase activities of peroxidase, polyphenol oxidase, and indole acetate oxidase and the contents of the endogenous hormones indole acetic acid (IAA), gibberellin (GA 3 ), and zeatin (ZT) were increased. IAA plays a key role in the process of adventitious root formation and the ratios of IAA/GA3, IAA/ABA, and IAA/ZT reflect endogenous hormone homeostasis during adventitious root formation. IAA/ABA and IAA/ZT showed higher values in the pruned roots compared to the control roots, which favor adventitious root induction and elongation. These results provide a basis for the study of adventitious root formation in tree peony.

Hydrogen-rich water enhanced salt tolerance in tomato seedlings by regulating strigolactone biosynthesis genes SlMAX1 and SlD27

“…The germinated seedlings were transferred into erlenmeyer asks containing 1/2 Hoagland solution for 4 d, and then transferred to 100% Hoagland solution for 7 d. After growing for approximately one month (four-leaf stage), seedlings with similar growth were collected and treated with different concentrations for 7 d. The seedlings root treated with the Hogland solution adding no extra compounds were served as control (CK). According to the previous study in our laboratory (Wang et al 2021;Liu et al 2022), the concentration of NaCl (150 mM), SLs synthesis mimic GR24 (15 µM), tricolactone synthesis inhibitor TIS108 (3 µM) and 75% HRW were selected. The treatments are as follows: CK (Hogland); NaCl (150 mM); NaCl (150mM) + HRW (75%); NaCl (150 mM) + GR24 (15 µM); NaCl (150 mM) + HRW (75%) + TIS108 (3 µM).…”

“…Root growth and development are determined by the synergistic action of multiple plant hormones, including indoleacetic acid (IAA), Gibberellic acid (GA 3 ) and zeatin (ZT) (Wang et al 2021). Meanwhile, Zhang et al (2009) found that IAA and nitric oxide (NO) may play a role in H 2 S-induced formation of adventitious roots in Ipomoea batatas, which signi cantly increased the number of long roots.…”

“…Meanwhile, Zhang et al (2009) found that IAA and nitric oxide (NO) may play a role in H 2 S-induced formation of adventitious roots in Ipomoea batatas, which signi cantly increased the number of long roots. In addition, abscisic acid (ABA) promoted root hair elongation by regulating root tip homeostasis through polar auxin transport (Wang et al 2021). Furthermore, GA 3 could regulate lateral root development in cucumber and signi cantly increased root dry weight (Cai et al 2022).…”

RNA Sequencing Analysis and Verification of Paeonia ostii ‘Fengdan’ CuZn Superoxide Dismutase (PoSOD) Genes in Root Development

“…It has a positive regulatory effect on root development via a mediating hormone [29,30]. Wang et al [31] also found that SOD activity played an important role in the root development of tree peony. However, there are still issues with root development in tree peony, and the molecular mechanism of its rooting is not fully understood.…”