Germination of coastalplain honeycombhead (Balduina angustifolia) in response to photoperiod, temperature and gibberellic acid

Abstract

Coastalplain honeycombhead (Balduina angustifolia) is underutilised in ecosystem restoration and pollinator conservation projects. Seeds collected from different populations throughout Florida, USA during 2007 and 2016-2018 were used in experiments that evaluated the effects of a 0 or 12-hour photoperiod, seasonal and standard temperatures, 0-5,000 ppm gibberellic acid (GA) or source population (northwest, central and south Florida) on seed germination. For central Florida seeds, germination was high (62-74%) in all seasonal temperatures except for summer (4%) and was not affected by photoperiod. Germination differed for two northwest populations and was higher in warm (35/25 and 30/20°C) temperatures compared with cool (25/15 and 20/10°C) temperatures (63-72% vs. 9-36%). In a one-year move-along experiment, germination was similar at all seasonal and constant temperatures for seeds from central, south-central and south Florida, while northwest Florida seeds had reduced germination under winter temperatures. Germination of northwest Florida seeds after exposure to GA increased for two of four and three of four populations for one year and five-day old seeds, respectively. There were different temperature requirements on a regional scale and different dormancy levels at a local scale for coastalplain honeycombhead.

Ornamental Invasive Plants in Florida with Research-founded Alternatives

“…When incorporated into appropriate spaces, native plants can offer desired aesthetic attributes such as color and form, while contributing biodiversity and function for ecologically friendly landscaping (Kalaman et al 2022a(Kalaman et al , 2022b). In the past 2 decades, significant progress has been made in the propagation, production, and landscape trialing of more than 15 native species that are either 1) attractive in their natural areas and have potential for the ornamental industry (Campbell et al 2021(Campbell et al , 2022; or 2) are already in limited cultivation, but merit widened use for landscapes and gardens (Smith et al 2022;Young et al 2022). This includes species such as squareflower (Paronychia erecta), coastalplain honeycombhead Nuclear DNA content and chromosome number was confirmed for five species within the porterweed complex (Qian et al 2021).…”

“…Seeds germinated under light or dark conditions, and germination was influenced by temperature and population (Campbell et al 2021). Seeds are orthodox and retained high viability after a year of storage.…”

“…Methodology of these studies typically began with determining initial seed viability using TZ testing, followed by germination tests conducted at four different temperatures that mimic seasons inFlorida [winter (22/11 C), early spring or late autumn (27/15 C), early autumn or late spring (29/19 C), and summer (33/24 C)] as described byCampbell et al (2022). Depending on the species, additional studies have been conducted to explore the effects of photoperiod, population, seed pretreatment, and seed storage on germination(Campbell et al 2021).…”