بررسی امکان نگهداری بذر تعدادی از گونه های مرتعی و بیابانی در شرایط فراسرد

Because of greatly decreased metabolic activities, longevity of cells under cryogenic condition is presumed can be extended almost to infinite. Precryopreservation treatments such as Vitrification (using PVS2), Desiccation have a positive effect on the seed's survival efficiency and length of preservation period under cryogenic conditions. Cryopreservation is an important and reliable approach of preserving plants' seeds, cells and vegetative organs. seeds of the following range and desert species: Ammodendron persicum, Centaurea lachnopus, Camphorosma monspeliaca, Kelussia odoratissima, Ferula gummosa, Medicago polymorpha, Medicago rigidula, Medicago sativa, Secale montanum, Smirnovia iranica and Trifolium radicosum collected from different habitats. The seed samples pretreated with Vitrification (using PVS2), Desiccation and 30% Glycerol, before transferring into liquid nitrogen (-196 C). Liquid nitrogen incubation periods of the seeds were from 1 week up to 26 month (depend on species). After removal of the seeds from liquid nitrogen, they were exposured to a heat shock (+42 C), washed, and evaluated by standard germination tests. Furthermore, the second samples of the same seeds were sown in pots and grown in greenhouse (22 4 C). Seed germination, root and shoot lengths, germination speed, root/shoot length ratio and seed vigor index (VI) were recorded and statistically analyzed. High level of recovery from liquid nitrogen (-196 C), seed germination, and other attributes, in either laboratory or greenhouse conditions, revealed the cryogenic (-196 C) tolerance of all of the species. The plants originated from cryopreserved seeds and grown under greenhouse conditions grew normally and did not show any abnormality, compared to those of control plants. The high recovery and germination percentage after cryopreservation as well as lack of significant differences among the pre-cryopreservation treatments and storage periods, indicated the success of long term seed preservation of range and desert species under sub-cool (-196 C) conditions. High seed germination percentage and other characteristics either in greenhouse or in vitro conditions, it is concluded that seeds of most of the range and desert species can be preserved under cryogenic (-196 C) conditions, using Desiccation as an excellent pre-cryopreservation treatment. Keywords: Cropreservation, PVS2, Plant Germ Plasm, Seed Cryopreservation, PVS2, Desiccation, 30% Glycerol, Vitrification, Range Plant Seeds, Plant Seeds,Ammodendron persicum, Centaurea lachnopus, Camphorosma monspeliaca, Kelussia odoratissima, Ferula gummosa, Medicago polymorpha, Medicago rigidula, Medicago sativa, Secale montanum, Smirnovia iranica Trifolium radicosum.

کلیدواژه ها:

علوفه دامی ، بذرها (گیاه شناختی) ، نگهداری ، حفاظت زیستی ، انجماد ، پلاسم زایشی