APPLICATION OF D CRYO-PLATE TECHNIQUE FOR THE CRYOPRESERVATION OF IN VITRO-GROWN SHOOT TIPS OF Tarenaya spinosa (CLEOMACEAE)

BACKGROUND: Tarenaya spinosa is a medicinal species used for treating respiratory and inflammatory diseases. Various biotechnological studies have been developed for in vitro establishment of plants and long-term conservation of this species. Objective: This study aimed to establish a new cryopreservation protocol using the D cryo-plate technique for in vitro-grown shoot tips of T. spinosa. MATERIALS AND METHODS: Different steps of the cryopreservation procedure were evaluated in this work: preculture; sucrose concentration of calcium alginate gel; concentration and time of exposure to osmoprotective loading solution; time of exposure to silica gel; and regrowth on recovery medium. RESULTS: The optimal procedure included preculture with increasing sucrose concentration (from 0.25 to 0.50 M), encapsulation and dehydration over silica-gel for 60 min. Increasing sucrose concentration in the loading solution or exposure duration had a negative effect on recovery of cryopreserved shoot tips. However, the association of calcium alginate gel enriched with 0.6 M sucrose with post-rewarming culture with BAP for 2 weeks resulted in the most efficient cryopreservation protocol (76% survival and 70% shoot recovery). CONCLUSION: The plants developed after cryopreservation maintained their in vitro multiplication capacity and demonstrated the efficiency of long-term conservation by D cryo-plate technique for T. spinosa.