Cryopreservation and assessment of genetic fidelity Acorus calamus Linn., an endangered medicinal plant.

BACKGROUND: Acorus calamus Linn. is a medicinally valuable monocot plant belonging to the family Acoraceae. Over-exploitation and unscientific approach towards harvesting to fulfill an ever-increasing demand have placed it in the endangered list of species. OBJECTIVE: To develop vitrification-based cryopreservation protocols for A. calamus shoot tips, using conventional vitrification and V cryo-plate. MATERIALS AND METHODS: Shoot tips (2 mm in size) were cryopreserved with the above techniques by optimizing various parameters such as preculture duration, sucrose concentration in the preculture medium, and PVS2 dehydration time. Regenerated plantlets obtained post-cryopreservation were evaluated by random amplified polymorphic DNA (RAPD) to test their genetic fidelity. RESULTS: The highest regrowth of 88.3% after PVS2 exposure of 60 min was achieved with V cryo-plate as compared to 75% after 90 min of PVS2 exposure using conventional vitrification. After cryopreservation, shoot tips developed into complete plantlets in 28 days on regrowth medium (0.5 mg/L BAP, 0.3 mg/L GA3, and 0.3 mg/L ascorbic acid). RAPD analysis revealed 100% monomorphism in all cryo-storage derived regenerants and in vitro donor (120-days-old) plants. CONCLUSION: Shoot tips of A. calamus that were cryopreserved had 88.3% regrowth using V cryo-plate technique and the regerants retained genetic fidelity. https://doi.org/10.54680/fr24210110412.

Cryopreservation of zygotic embryos of Podophyllum hexandrum Royle, an endangered medicinal plant, by vitrification and v cryo-plate techniques.

BACKGROUND: Podophyllum hexandrum is a highly endangered valuable medicinal plant of the Himalayas belonging to family Berberidaceae. This plant needs conservation efforts due to the over-exploitation and unscrupulous harvesting from the wild because of its ever-increasing demand. OBJECTIVE: To establish a long-term cryopreservation method for Podophyllum hexandrum using two techniques: Vitrification and V Cryo-plate. MATERIALS AND METHODS: Zygotic embryos were cryopreserved using vitrification and V cryo-plate by optimization of parameters including preculture time, loading time and PVS2 dehydration time. Recovery of zygotic embryos was performed on different regrowth media for plantlet formation. RESULTS: With V cryo-plate, 90% regrowth was obtained as compared to 73.3% with vitrification. V Cryo-plate conditions were pre-culture of zygotic embryos in 0.3 M sucrose for 4 days, treatment in loading solution with 0.8 M sucrose for 20 min, dehydration in PVS2 for 50 min, LN exposure, unloading in 1.2 M sucrose for 20 min and transfer of zygotic embryos to regrowth medium for recovery. During recovery, the maximum number of shoots (4.2) and highest shoot length (5.1 cm) were observed on regrowth medium with 1.5 mg per liter BAP and 0.1 mg per liter IAA (R7). CONCLUSION: Zygotic embryos of Podophyllum hexandrum were cryopreserved with 90% regrowth using a V cryoplate technique and plantlets were produced directly after cryopreservation. Doi: 10.54680/fr23410110712.

Cryopreservation of a threatened medicinal plant, Valeriana jatamansi Jones, using vitrification and assessment of biosynthetic stability of regenerants.

BACKGROUND: Valeriana jatamansi Jones is a medicinal plant of the Himalayan region with high trade value. Since overexploitation of this wild species led it to be listed as threatened, a comprehensive conservation strategy is needed. Cryopreservation would be a useful complementary method to conventional conservation methods. OBJECTIVE: To develop a cryopreservation protocol for V. jatamansi with maintenance of biosynthetic stability of regenerants. MATERIALS AND METHODS: In vitro shoot tips were cryopreserved using vitrification with either PVS2 or PVS3 and the efficacy of the two cryoprotectant mixtures compared. Regenerated plantlets were evaluated by HPLC analysis for contents of four valepotriates viz. valtrate, acevaltrate, didrovaltrate and IVHD valtrate. RESULTS: The highest shoot recovery (91.6%) after transfer to liquid nitrogen was obtained when shoot tips were treated with PVS2 at 0°C for 110 min, which was significantly higher than the highest recovery (73.3%) obtained using PVS3 for any duration tested. Evaluation of biosynthetic stability showed no variation in valepotriate contents between in vitro maintained and cryopreserved derived plantlets. CONCLUSION: This protocol will be useful for the long-term conservation of this species as high frequency recovery and biosynthetic stability after cryopreservation were obtained.