كليدواژه :
رشد گياهچه , اكوتيپهاي يونجه چند ساله (Medicago sativa L.) , تنش كم آبي , جوانهزني
چكيده لاتين :
To study the response of 10 different perennial alfalfa ecotypes to water deficit stress at germination stage, an experiment was conducted in controlled environment. The experiment was performed in a complete block design arrangement, in factorial of three replications. Throughout the research, the effect of six levels of osmotic potential (0, -4, -6, -8, -10 and -12 bar) resulting from polyethyleneglycol 6000 (PEG 6000) were investigated on germination indexes of ten different perennial alfalfa ecotypes including six Iranian ecotypes (Gharah yonje, Hamedani, Farahane Arak, Synthetic Karaj, Mohajeran Karaj and Shorkat) and four foreign ones (Harp, Jolia, Deft and Dian). The traits of: germination rate and germination percentage, root and shoot lengths, seedling dry weight, and root to shoot dry weight ratio were investigated. Results indicated that water deficit influenced seed germination traits in alfalfa (p<0.01). There were significant differences observed among ecotypes for the above mentioned traits. In general there were not significant differences among ecotypes for seed germination at water deficit up to -4 bar. Water deficit up to -4 bar increased root and shoot length and weights of alfalfa seedlings, resulted in enhancement of seedling dry weight. Root to shoot dry weight ratio also increased with water deficit up to -4 bar. In high water deficits (between -6 and -8 bar) the above mentioned traits were severely decreased.
