JWSS - Journal of Water and Soil Science

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Germination of strawberry seeds from self- and cross pollination of 4 commercial cultivars were evaluated under mist and in vitro cultures. The study was conducted in McGill University in Quebec, Canada, during 1994 and 1995. Self-pollination of Chambly and Redcoat cvs., and cross pollination of Oka × Chambly as well as Redcoat × Veestar and their reciprocals were used. At maturity, fruits were harvested and their seeds were separated. A sample of each seed lot was grown in greenhouse under mist condition and in vitro using MS medium. In the latter, both intact and cut seeds were used. Germination index (containing germination velocity and rate) was used as a criterion for germination evaluation. The results showed that there was no sign of germination in intact seeds 40 days after cultivation on MS medium however, cut seeds containing plantlets started germination 2 days after cultivation and obtained 90 percent of the germination after one week of culturing on the medium. Germination of seeds under mist condition began 15 days after sowing and showed a minimum of 55 to 87 percent in different genotypes till the end of the experiment period (60 days). Germination index (GI) under this condition ranged from 15.4 to 26.1. GI comparison of seeds under in vitro and mist conditions indicates a lower germination rate in different genotypes under mist condition. This study also showed that the rate of germination in strawberry seeds could range from 0 to 100 percent depending on genotype and type of treatment used. The best treatment for a synchronized and rapid germination was found to be using cut seeds containing the plantlets on MS medium.

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Isolating and cloning of plant protease inhibitor (PIs) genes and transforming them to the genome of other plants have paved the way for producing resistant transgenic plants against pests. Knowing that cystatins act as inhibitor factor against cysteine protease, short and long cystatin genes were isolated from maize mRNA. By using specific primers, cDNA of these genes were constructed and cloned in pUC19 and pGEX 2T plasmid vectors. The recombinant plasmid vectors were then transformed to E. coli (strain DH5 α) competent cells using electroporation. The competent cells harboring the clones were grown in suitable medium and cystatin proteins fused to Glutation-S-transferase (GST) were purified by glutation agarose bead filter. In each step of the procedure the presence of cystatin genes were confirmed through electrophoresis. Further evaluation proved the inhibitory effect and a mild stability of at least one of the corn cystatin (CC II) when incubated with cysteine protease.