Stempelets

Stempelets are small, spherical or ovoid propagules designed for clonal plant propagation. They typically consist of a shoot apical meristem embedded in a supportive tissue, enclosed within a protective hydrogel or alginate matrix to form a pellet a few millimeters in diameter.

Production involves excising meristem tissue from source plants, establishing in vitro cultures to promote shoot initiation, selecting healthy meristems, and encapsulating them in calcium alginate beads. The resultant stempelets can be dried or stored briefly before use, and rehydrated upon planting.

Uses include rapid multiplication of desirable cultivars, uniform plant material, and disease-free stock. They are used in horticulture, forestry, and breeding programs to deliver comparable growth across batches and to facilitate transport to nurseries.

Advantages include higher propagation rates, reduced contamination risk, ease of transport and storage, and standardized dosages. Limitations include higher production costs, need for sterile handling, cultivar dependence, and regulatory considerations for in vitro propagated materials.

History and development: Stempelets emerged from advances in plant tissue culture and microencapsulation techniques in the late 20th and early 21st centuries, combining meristem culture with encapsulation to create durable propagules.