In vitro seed germination and seedling performance of Hibiscus coddii subsp. barnardii

Abstract

Hibiscus coddii subsp. barnardii is an endemic South African plant species with ornamental potential. The limited plant availability in nature and restrictions on the collection of living plant material (cuttings) for cultivation purposes, necessitated the development of a protocol for in vitro seed propagation to ensure all year round ex vitro establishment of plants. The effect of culture medium on seed germination and seedling performance was therefore studied. Various types of sterile seed cultures, namely moist filter paper bridges, five different strengths (¼, ½, –, full, 1¼) of PGR-free Murashige and Skoog medium (MS) and solid Gelrite® medium (control) were investigated. High germination percentages (85%-98%) were found in all three seed cultures, although seeds germinated on filter paper, Gelrite ® and lower strengths (¼, ½, –) of MS medium had shorter mean germination times (1.6-2.8 days) than those germinated on full and 1¼ strengths (3.5-4 days) of MS medium. Furthermore, the growth performance of seedlings varied with the strength of MS medium and was best supported on full strength MS medium, whereas ¼ and ½ strength MS media and Gelrite® cultures were detrimental for seedling growth.

Preliminary study on in vitro shoot culture of Hibiscus coddii subsp. barnardii, an indigenous South African flowering plant

“…Aseptic seedlings (5-6 weeks old) derived from chemically scarified and disinfected (Du Plessis et al, 2020) seeds germinated on PGR-free MS medium were also used to obtain aseptic shoot explants that did not require disinfection. Seedlings were aseptically transferred to a Petri dish lined with sterile distilled water to prevent wilting, and the roots were removed.…”

“…However, reliable propagation methods for this plant are needed for horticultural and conservation purposes. Our previous studies have shown that the plant can be successfully propagated in vivo and in vitro by seeds (Du Plessis et al, 2019;Du Plessis et al, 2020), although only one plant per seed is produced, resulting in low regeneration efficiency. In vitro micropropagation offers the potential to produce a large number of plants from one aseptic explant in a short period of time (Chen, 2016).…”

In vitro germination and controlled release fertilizer effects on ex vitro development of Eugenia uniflora L. plantlets

“…Thus, in vitro seed germination could develop healthy selected plantlets for breeding programs, which has been reported in many crops such as papaya, 11 cherimoya, 12 hop, 13 bramble, 14 and several Citrus species 15,16 . The effects of temperature, light, pre‐soaking treatment, and gibberellin concentration have earlier been reported to affect in vitro germination of various species 17–20 …”

“…15,16 The effects of temperature, light, pre-soaking treatment, and gibberellin concentration have earlier been reported to affect in vitro germination of various species. [17][18][19][20] In addition to increasing germination, in vitro techniques can be effective to overcome problems related with seedling establishment and acclimatization. The soil quality impacts directly on seedling growth and to promote efficient seedling development, it is crucial to use substrates that can provide correct the physical-chemical properties and nutrient requirements for plants.…”