Investigation of degradation process of Zygophyllum fabago L. seed reserves during germination under different pH

Abstract         Zygophyllum fabago L. a facultative Perennial halophyte, is grown in arid and inert areas. Due to the different acidity of the soil in natural habitats of Zygophyllum, the effect of pH on the process of seed reserves decomposition during germination was examined. The experiment was conducted in a completely randomized design with seven pH levels (4, 5, 6, 7, 8, 9 and 10) and four replicates in a week. The seeds were surface sterilized by hypochlorite 1% and were placed at different pHs, 28°­C and darkness. Seed biomolecules and activity of alpha-amylase and lipase enzymes were carried out in two stages before (fifth day) and after (seventh day) of germination. The results of the analysis of variance showed that the lipase enzyme was more active in alkaline pH and therefore the lipid level was lower in these pHs. Alpha-amylase has been shown to be less active at alkaline pH than acidic pH. The concentration of seed starch reserves and the content of soluble sugars was followed by alpha-amylase activity. It seems that in the Zygophyllum seed, the activity of the alpha-amylase enzyme before the germination was maximum in the range of 4 to 8, which caused the degradation of the starch deposits, thereby triggering the germination process. Whiles lipase activity and lipid content indicated the importance of lipid reserves after germination. After germination, lipase can provide growth promoters (and probably no energy prognosis) for seedlings that are more considerable in alkaline environments. The highest protein content of the seeds was observed after germination and at neutral pH levels, which could indicate optimum conditions for seedling growth.