Seed Dormancy Class and Ecophysiological Features of Veronicastrum sibiricum (L.) Pennell (Scrophulariaceae) Native to the Korea Peninsula.

Gyeong Ho Jang,Seung Youn Lee,Yong Ha Rhie,Jae Min Chung

doi:10.3390/plants11020160

Abstract

Veronicastrum sibiricum is a perennial species distributed in Korea, Japan, Manchuria, China, and Siberia. This study aimed to determine the requirements for germination and dormancy break of V. sibiricum seeds and to classify the kind of seed dormancy. Additionally, its class of dormancy was compared with other Veronicastrum and Veronica species. V. sibiricum seeds were permeable to water and had a mature embryo during seed dispersal. In field conditions, germination was prevented by physiological dormancy, which was, however, relieved by March of the next year, allowing the start of germination when suitable environmental conditions occurred. In laboratory experiments, the seeds treated with 0, 2, 4, 8, and 12 weeks of cold stratification (4 °C) germinated to 0, 79, 75, 72, and 66%, respectively. After the GA3 treatment (2.887 mM), ≥90% of the seeds germinated during the four incubation weeks at 20/10 °C. Thus, 2.887 mM GA3 and at least two weeks at 4 °C were effective in breaking physiological dormancy and initiating germination. Therefore, the V. sibiricum seeds showed non-deep physiological dormancy (PD). Previous research, which determined seed dormancy classes, revealed that Veronica taxa have PD, morphological (MD), or morphophysiological seed dormancy (MPD). The differences in the seed dormancy classes in the Veronicastrum-Veronica clade suggested that seed dormancy traits had diverged. The results provide important data for the evolutionary ecological studies of seed dormancy and seed-based mass propagation of V. sibiricum.

Highlights

The most important role of seeds is to keep a species in existence
Veronicastrum sibiricum, which is endemic to Northeast Asia, is distributed in the central and northern parts of the Korean Peninsula, Far East Russia, Northeast China, Mongolia, and Northern Japan [3]
This study aimed to investigate the seed ecology and physiological characteristics of V. sibiricum native to the Korean peninsula, to classify its seed dormancy, and develop technology for mass propagation based on the acquired ecophysiological information

Summary

Introduction

The most important role of seeds is to keep a species in existence. Plants have evolved various strategies to ensure successful germination of seeds [1]. The success of seed germination and seedling establishment can affect features for the propagation of plant species, which are of both economic and ecologic importance [2]. The species of Veronicastrum and its closely related genus Veronica are widely distributed in the Northern Hemisphere, and in several regions in the Southern Hemisphere [5]. Both Veronicastrum and Veronica are morphologically closely related. The phylogenetic analysis based on DNA sequences, seed microstructure [7], and pollen [8] indicate similarity between the two genera

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