Open Access

ARTICLE

Effect of Paclobutrazol Application on Plant Growth and Flower Quality in Herbaceous Peony

by Yanqing Wu^1,2, Jiao Liu¹, Daqiu Zhao², Jun Tao^1,2,*

1 Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, 225009, China
2 Jiangsu Key Laboratory of Crop Genetics and Physiology, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, 225009, China

* Corresponding Author: Jun Tao. Email:

Phyton-International Journal of Experimental Botany 2022, 91(9), 2017-2032. https://doi.org/10.32604/phyton.2022.020643

Received 04 December 2021; Accepted 12 January 2022; Issue published 13 May 2022

Abstract

Herbaceous peony (Paeonia lactiflora Pall.) is an important ornamental plant worldwide. In its natural state, P. lactiflora often manifests traits like rapidly elongating internodal growth, loose plant types, and soft inflorescence stems. However, very little has been known about the measures for controlling these traits. This study investigated the effect of applying paclobutrazol (PBZ) on the plant growth and flower quality in P. lactiflora. The results indicated that PBZ application reduced the plant height (8.05%), plant crown width (14.72%), and leaf area (10.90%), but increased the leaf thickness (18.18%) and stem diameter (over 11%) in P. lactiflora. Meanwhile, PBZ application was also found to increase the chlorophyll (Chl) a (29.63%), Chl b (33.33%), Chl a+b (30.56%), SPAD (27.32%), relative water content (0.47%), soluble sugar (5.09%) and activities of three antioxidant enzymes (superoxide dismutase 169.66%, peroxidase 3.59%, catalase 319.30%), but decreased the relative electrical conductivity (18.52%). Additionally, the application of PBZ was found to affect the flowering quality of P. lactiflora, increasing the flower diameter and fresh weight only in the flower-bud stage. This initiates the bloom stage, where there was a decrease in the total content of the aromatic compounds except for the flower-bud stage, and faded the flower color by reducing the content of anthocyanin. These results demonstrated that the application of PBZ can regulate the P. lactiflora plant types with no significant decrease in its ornamental values. This might provide a theoretical basis for further applying PBZ in P. lactiflora for use in urban landscape spaces.

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