Preliminary studies on allelopatic effect of some woody plants on seed germination of rye-grass and tall fescue.

In order to investigation of allelopathic effects of some ornamental trees on seed germination of rye-grass (Lolium prenne) and tall fescue (Festuca arundinaceae), this experiment was conducted in a randomized complete block design with 3 replicates at the laboratory of Horticultural Sciences Department of Ferdowsi University of Mashhad, during 2008. In this research, we studied the effect of aqueous and hydro-alcoholic extracts of Afghanistan pine (Pinus eldarica), arizona cypress (Cupressus arizonica), black locust (Robinia psedue acacia) and box elder (Acer negundo) leaves that prepared in 1:5 ratio on seed germination percent and rate for two grasses. The results showed that all extracts decreased statistically seed germination in compared to control treatment. The highest germination percentage and germination rate of tested grass detected in control treatment. Hydro-alcoholic extracts of all woody plants (15, 30%) were completely inhibited seed germination of rye-grass and tall fescue. Also aqueous extract of arizona cypress was completely inhibited seed germination of tall fescue and had more inhibitory activity than other aqueous extracts on rye-grass. Between aqueous extracts, the highest and lowest seed germination of rye-grass was found in Afghanistan pine and arizona cypress, respectively.

The effect of seed extraction methods on seed quality of two cultivar's tomato (Solanum lycopersicum L.).

In order to compare of different methods and identify the optimum condition for tomato seed extraction, factorial experiments with 3 replications was conducted. In the first experiment, pulp of two tomato cultivars (Faraon, Dominator) were fermented at two temperatures (25, 35 degrees C) and six periods (24, 48, 72, 96, 120, 144 h). The germination of seeds in laboratory as well as seedling emergence and preliminary growth in greenhouse were studied and measured. The results showed that effect of cultivar on traits (except of seedling emergence) was significant. Also the effect of temperature of fermentation, duration of fermentation and also interaction effects of them on seed germination were significant. Totally seed quality decreased with increasing temperature and duration of fermentation and the fermentation duration from 24 to 48 h at temperature 25 degrees C, is recommended. In the second experiment, tomato seeds were extracted by HCL (pH was arranged to 1, 2, 3 for 10, 20, 30 min), H2SO4 (pH was arranged to 1, 2, for 15, 30 min), Sodium carbonate (5, 10% for 24 and 48 h) and fermentation. Percentage germination, germination rate, length of radicle and length of plumule were used for seed quality assessment. The results showed that interaction effect between pH and duration of HCL treatments was significant for seed germination (percentage and rate) and there was an interaction effect between concentration and duration for germination rate in alkali treatments. Different extraction methods had not detrimental effect on percentage germination, but acid treatments produce very bright clean seeds in compare to other treatments.