Articles
Seed cryopreservation and cold storage of two orchids, Phaius tankervilleae and Paphiopedilum spicerianum
Article number
1455_15
Pages
121 – 130
Language
English
Abstract
Phaius tankervilleae is a terrestrial orchid of medicinal and ornamental value, while Paphiopedilum spicerianum is a critically endangered terrestrial or semi-epiphytic herbaceous orchid.
Seeds of P. tankervilleae were collected from slightly dehiscent capsules and equilibrated at 15, 30, 50, and 75% relative humidity (RH) before stored at -20°C (cold storage) and in liquid nitrogen (LN, cryopreservation). For P. spicerianum, seeds collected 365 days after pollination (DAP) underwent similar equilibration and were stored at 4°C, -20°C, and in liquid nitrogen.
Tetrazolium staining showed that P. tankervilleae seeds retained ≥64% viability after storage; however, this represented a significant decline relative to fresh seeds.
Moreover, more than 52% seeds germinated after cryopreservation for 6 months.
For P. spicerianum, no significant viability loss occurred after cryopreservation for 6 months, and no significant reduction of germination were detected for seeds that stored at -20°C and in liquid nitrogen for 6 months.
Differential scanning calorimetry (DSC) analysis revealed that once the eRH was ≤75%, no free water was detected in the seeds and most seeds survived subsequent cold storage and cryopreservation.
The initial moisture content (MC) of freshly matured P. tankervilleae seeds was 10.64%; while, that of freshly matured P. spicerianum seeds was 37.27%. The lower initial MC and better storage performance of P. tankarvilleae suggested that its seeds were more mature than that of P. spicerianum. These results demonstrate that it is possible to store mature seeds of both species for long-term ex situ conservation.
Seeds of P. tankervilleae were collected from slightly dehiscent capsules and equilibrated at 15, 30, 50, and 75% relative humidity (RH) before stored at -20°C (cold storage) and in liquid nitrogen (LN, cryopreservation). For P. spicerianum, seeds collected 365 days after pollination (DAP) underwent similar equilibration and were stored at 4°C, -20°C, and in liquid nitrogen.
Tetrazolium staining showed that P. tankervilleae seeds retained ≥64% viability after storage; however, this represented a significant decline relative to fresh seeds.
Moreover, more than 52% seeds germinated after cryopreservation for 6 months.
For P. spicerianum, no significant viability loss occurred after cryopreservation for 6 months, and no significant reduction of germination were detected for seeds that stored at -20°C and in liquid nitrogen for 6 months.
Differential scanning calorimetry (DSC) analysis revealed that once the eRH was ≤75%, no free water was detected in the seeds and most seeds survived subsequent cold storage and cryopreservation.
The initial moisture content (MC) of freshly matured P. tankervilleae seeds was 10.64%; while, that of freshly matured P. spicerianum seeds was 37.27%. The lower initial MC and better storage performance of P. tankarvilleae suggested that its seeds were more mature than that of P. spicerianum. These results demonstrate that it is possible to store mature seeds of both species for long-term ex situ conservation.
Authors
H. Dai, K. Thammasiri, H.W. Pritchard, Y. Luo, X.J. Wang, H.P. Xi, F.C. Wu, X.J. Hu
Keywords
orchid seed storage, equilibrium relative humidity, differential scanning calorimetry (DSC), seed maturity, seed banking
Online Articles (41)