Abstracts: CryoLetters 21 (4), 2000

CryoLetters is a bimonthly, international journal for low temperature science and technology

CryoLetters 21, 203-214 (2000)
CryoLetters, c/o Royal Veterinary College, London NW1 0TU

Sub-zero cooling synchronizes post-diapause development of codling moth, cydia pomonella

Lisa G. Neven*, Holly J. Ferguson, Alan Knight

USDA-ARS, 5230 Konnowac Pass Road, Wapato, WA  98951, USA


 Sub-zero cooling treatments of -10°C and -15°C for 2-6 days were evaluated as a means of meeting the chilling requirement of diapause and to synchronize post-diapause development in larvae which were held in diapause for less than 6 months.  Sub-zero cooling did not affect male longevity. After six months in diapause, diapause/cooled females were longer lived than diapause control females but not longer than non-diapause females. In general, diapause-cooled males passed more spermatophores than males from control diapause and non-diapause groups.  In general, sub-zero cooling did not consistently affect fecundity and % egg hatch. Non-diapause females laid the most eggs after six months in diapause, and diapause-cooled females laid the most eggs after seven months in diapause.  The duration of sub-zero cooling had a significant effect on post-diapause emergence in relation to the duration that the larvae were in diapause. Sub-zero cooling for 4 days at -10°C significantly reduced the number of days to adult emergence of larvae which had been in diapause for 0-4 months. Sub-zero cooling at -15°C for durations of 2, 4, and 6 days had more variable effects on emergence, but in most cases, sub-zero cooling reduced the amount of time to and span of adult emergence.

Keywords: codling moth, diapause, insect rearing, longevity, fecundity, spermatophore transfer



CryoLetters 21, 215-222 (2000)
© CryoLetters, c/o Royal Veterinary College, London NW1 0TU

development of a shoot-tip vitrification protocol and COMPARISON with encapsulation-based PROCEDUreS FOR PLUM (Prunus domestica L.) CRYOPRESERVATION

Anna De Carlo, Carla Benelli and Maurizio Lambardi*

Istituto sulla Propagazione delle Specie Legnose, CNR/National Research Council, via Ponte di Formicola 76, 50018 Scandicci (Firenze), Italy
* to whom correspondence should be addressed. E-mail:


Cryopreservation of plum (Prunus domestica L.), cv Regina Claudia, was obtained by a vitrification/one-step cooling procedure of shoot tips from cold-hardened in vitro-grown plants. Best survival (57%) was obtained when the shoot tips were precultured at 4°C for 2 days on 0.09 M sucrose-containing Quoirin and Le Poivre medium, loaded for 30 min with a cryoprotectant (2 M glycerol and 0.4 M sucrose), incubated with the PVS2 solution at 0°C for 90 min, and directly plunged into liquid nitrogen. After re-warming in a waterbath at 40°C, the shoot tips were washed in a 1.2 M-sucrose MS solution for 20 min and finally plated on a regrowth medium. In comparison with the one-step cooling procedure, both the slow cooling  (-0.5°C min-1 up to -45°C), and the two-step cooling (-160°C for 25 min, then –196°C) gave lower percentages of shoot-tip survival. Among the other cryogenic procedures tested, the performance of the encapsulation-vitrification method was similar to the vitrification protocol in terms of shoot-tip regrowth (47.5%), while encapsulation-dehydration was unsatisfactory.

Keywords: Prunus domestica, plum, cryopreservation, vitrification, germplasm conservation.



CryoLetters 21, 223-230 (2000)
© CryoLetters, c/o Royal Veterinary College, London NW1 0TU


G.D. Rogge, A.M.Viana & A..M.Randi*

Departamento de Botânica, Universidade Federal de Santa Catarina, Florianópolis, SC,CEP 88040-900- Brazil.
*To whom correspondence should be addressed


Spores of Dicksonia sellowiana (Presl.) Hook., an endangered tree fern, were stored in liquid nitrogen. Surface sterilized spores were  placed in 1 ml sterile polypropylene cryotubes and  were plunged into liquid nitrogen cryo-cans for 15 minutes, 15 days, 1 month and 3 months. In all, of the treatments the percentage of germination was higher than the control (fresh spores). Germination in Dyer and MS media supplement with 10-7 M and  5x10-7 M BA was also promoted as comparing to control. There was no difference between the germination of spores thawed rapidly in a water bath at 45oC during 5 minutes or slowly at room temperature. Cryopreservation seems to promote germination of some dormant spores of D. sellowiana. The pre-treatment in cryoprotective solution of dimethyl sulphoxide 15%(v/v) in 1M(v/v) glycerol inhibited the germination of cryopreserved spores.

Key words: Dicksonia sellowiana, spore, medium term cryogenic storage, germination

Abbreviations: BA-benzyladenine, DMSO-dimethyl sulphoxide, GA3-gibberelic acid, MS-Murashige and Skoog medium



CryoLetters 21, 231-236 (2000)
© CryoLetters, c/o Royal Veterinary College, London NW1 0TU


Barbara Gajda* and Zdzisław Smorąg

Department of Animal Reproduction, National Research Institute of Animal Production, 32-083 Balice/Kraków, Poland


The aim of this experiment was to examine the survival of porcine embryos following exposure to vitrification solutions and vitrification. The work was carried out on non-cultured and cultured morulae and blastocysts. The viability of treated embryos was assessed by their ability to develop in in vitro culture. The results showed that the most detrimental step in the vitrification of pig embryos is exposing them specifically to a vitrification medium rather than the vitrification process itself. Moreover, we demonstrated the beneficial effect of culture on the viability of pig embryos after vitrification.

Keywords: vitrification, pig, embryo, culture, in vitro survival.



CryoLetters 21, 237-244 (2000)
©CryoLetters, c/o Royal Veterinary College, London NW1 0TU


Kanchit  Thammasiri

Department of Plant Science, Faculty of Science, and Institute of Science and Technology for Research and Development, Mahidol University, Rama VI Road, Phyathai, Bangkok 10400, Thailand E-mail:


 Seeds from selfing of a Thai orchid (Doritis pulcherrima Lindl.) were successfully cryopreserved in liquid nitrogen (LN) using the vitrification method.  Seeds from 3-month-old pods were sufficiently dehydrated in 2 ml cryotubes filled with highly concentrated vitrification solution (PVS2) at 25 2C for 50 min. The seeds were then rapidly plunged into LN. After rapid warming, the PVS2 solution was replaced with 0.5 ml of 1.2M sucrose in modified Vacin and Went (1949) (VW) solution and kept at 25 2C for 20 min prior to transfer on VW agar medium.  About 62% of cryopreserved seeds treated with PVS2 solution were able to develop into normal seedlings while without that treatment there was no survival. This vitrification protocol appears to be a promising technique for the cryopreservation of some Thai orchid germplasm.

Keywords: Doritis pulcherrima Lindl., cryopreservation, seeds, Thai orchid, vitrification.



CryoLetters 21, 245-254 (2000)
© CryoLetters, c/o Royal Veterinary College, London NW1 0TU

Experimental measurement and theoretical analyses of the freezing-thawing processes around a probe

J.Zhang, T.C.Hua*, E.T.Chen

 Institute of Cryobiology and Food Freezing, University of Shanghai for Science and Technology, No.516, Jun Gong Road, Shanghai, 200093, China


Both the experimental and the analytical studies of the freezing/thawing process around a cryosurgical cylinder probes in a simulative biological tissue are presented in this paper. The enthalpy method and the finite element scheme are applied to solve the multidimensional phase change problems in cryosurgery. A very good agreement is found between the computed solutions and the experimental results. The influences of different cooling-warming schemes of the probe on the ice ball development, the temperature variation, the axial and the radial temperature gradients inside the tissues, and the requirement of cooling power are analyzed.    

Keywords: cryosurgery, cryoprobe, phase-changing problem, heat transfer, enthalpy method



CryoLetters 21, 255-260 (2000)
© CryoLetters, c/o Royal Veterinary College, London NW1 0TU

The pattern of freezing of grapevine shoots during early bud growth

Faisal Hamed1, Michael P. Fuller*2 and Ghassan Telli3

1 Department of Horticulture, Faculty of Agriculture, University of Damascus, Syria
2 Department of Agriculture and Food Studies, Seale-Hayne Faculty, University of Plymouth, Newton Abbot, Devon, TQ12 6NQ, UK.
3 Department of Horticulture, Faculty of Agriculture, Al-Baath University, Homs, Syria
*author for correspondence –


 The pattern of freezing of two varieties of grapevine during spring bud burst was characterised using infrared thermography. All plants studied showed endogenous freezing of the stems and subsequent rapid ice spread (0.47 cm s-1) analogous to ice spread in bulk water suggesting ice travel in the xylem. Barriers to ice spread were observed between stembranches and more importantly between the stem and buds. Buds froze after the stem and freezing appeared to be initiated from the stem. The lack of a fully functional xylem system is proposed as the barrier to ice spread. All buds which froze suffered complete frost kill whilst frozen stem recovered unharmed. Only 58% of the buds froze and those that did not freeze survived completely.

Keywords: Ice nucleation, exotherm, grapevine, frost damage, infrared thermography

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