Stimulatory and inhibitory effects of light on Cereus repandus (Cactaceae) seed germination are strongly dependent on spectral quality.

Resource type
Journal article
Creator (person)
Yang, X-Y.
Pritchard, Hugh W.
Date published
September 6, 2022
Abstract
In small seeds, light often promotes germination and longer-term exposure to darkness reduces light sensitivity. In cacti inhabiting harsh environments, a rapid response to light exposure is potentially advantageous for seedling establishment. We exposed dark-imbibed seeds of the cactus to doses of red (RED) light and far-red (FR) light. The seeds exhibited positive photoblastism to RED light. Although the initial levels of germination varied between seed lots, the sensitivity to increasing the RED dose did not. As little as 5 min per day for 4 d was sufficient to saturate the light requirement for germination. The effects of RED light were reversed by FR exposure as long as the interval between RED and FR did not extend to 2 d, by which time the seeds had ‘committed’ to germinate. Dark incubation for 1–2 weeks prior to RED exposure reduced light sensitivity in two seed lots, such that RED only promoted around 20% germination. Phytochrome is assumed to mediate the reversibility of the RED:FR response. High sensitivity to light spectral quality suggests that seeds of are able to germinate quickly in high-quality microsites, but seed burial or shading may commit the seeds to form a soil seed bank. The light characteristics of the germination trait in this species are typical of many small seeded species of the drylands.
Project(s)
Priority 2: Trait Diversity and Function
Funder
Funder nameAwards
Chinese Academy of Sciences, China
Xishuangbanna Tropical Botanical Garden, China
Jilin Agricultural University, China
Millennium Seed Bank Project
Royal Botanic Gardens, Kew, United Kingdom
Journal title
Seed Science Research
Publisher
Cambridge University Press (CUP)
Place of publication
Cambridge, UK
ISSN
0960-2585
eISSN
1475-2735
Official URL
Related URL
Rights statement
In Copyright
DOI
Keywords
Additional information
IF = 2.25 (2021-2022)