Geobotanical Study and Preservation of Rare and Endangered Rosaceae Species

Abstract

The loss of plant species, especially endangered and endemic ones, poses a significant threat to global biodiversity. These species cannot easily be replaced when their populations decline or become extinct, which makes their loss particularly devastating. This study focuses on the geobotanical study of nine Rosaceae species (Cotoneaster karatavicus, Crataegus ambigua, Malus niedzwetzkyana, Malus sieversii, Prunus tenella, Prunus ulmifolia, Sibiraea laevigata, Sorbus persica, and Spiraeanthus schrenkianus) and the development of ex situ approaches for the conservation of Rosaceae species listed in the Red Book of Kazakhstan. The geobotanical study revealed an alarming trend of biodiversity loss in five regions of Kazakhstan. This loss is driven by threats from diseases and pests, as well as the aging of plants, small population sizes, weak in situ fruiting, and other factors, such as climate change. We have established an in vitro collection for the short- and medium-term conservation of seeds, embryos and shoots taken either directly from field-grown plants or from budwood cuttings forced indoors. We also use long-term sexual conservation methods, such as the cryopreservation of seed and embryonic axes, alongside conventional seed banking at -20 °C. Ex situ conservation efforts that use multiple propagules and storage methods for the same species are well-suited to a diverse genebank facility. These efforts enable future generations to use this valuable reservoir of genetic diversity for crop improvement and may also serve as a basis for propagating planting material to restore degraded populations.

Keywords: cryopreservation; genetic diversity; in vitro collection; plant tissue culture; wild species.

Figure 1

Natural populations of Rosaceae species conserved in in situ conservation sites in Kazakhstan, their fruit appearance and herbarium collections. (A1), (A2), and (A3): Cotoneaster karatavicus; (B1), (B2), and (B3): Crataegus ambigua; (C1), (C2), and (C3): Malus sieversii; (D1), (D2), and (D3): Prunus tenella; (E1), (E2), and (E3): Sibiraea laevigata; (F1), (F2), and (F3): Spiraeanthus schrenckianus; (G1), (G2), and (G3): Sorbus persica; (H1), (H2), and (H3): M. niedzwetzkyana; (I1), (I2), and (I3): P. ulmifolia.

Figure 2

Map of regions in Kazakhstan where Rosaceae species were collected in 2023–2024. The collection sites are marked in green and the species are represented by colored stars.

Figure 3

Flowchart depicting the strategies used for the in vitro establishment of Rosaceae species using sexual and asexual sources of explants. (A) Seeds were either placed in (B) plastic containers filled with perlite and stratified at 4 °C for 8 weeks before being exposed to 24 ± 1 °C and germinated to provide shoots for (C) in vitro initiation, or stratified at 4 °C for 8 weeks, sterilized in mercuric chloride (HgCl₂) and (D) germinated on culture media. As an alternative strategy, (E) seeds were stratified at 4 °C for 8 weeks, (F) embryonic axes were isolated, sterilized in HgCl₂ and (G) germinated on culture media. Shoots were taken either directly from the (H1) plants in the field or by (H2) sprouting new shoots (in the laboratory) from cuttings taken from dormant mother plants and used as explants for (I) in vitro initiation. In vitro cultures were then screened for endophytes using bacteriological growth media and healthy-looking shoots were used to establish stock cultures.

Figure 4

Seeds of Rosaceae species stored at the Institute of Plant Biology and Biotechnology, Almaty, Kazakhstan. Seeds were partially dehydrated and transferred to 90 × 90 mm aluminum foil laminate bags (A,B), hermetically sealed (C) and stored at −20 °C (D), or transferred to cryovials (E) and stored at −196 °C (F).