Seed germination response of Haloxylon persicum (Chenopodiaceae) to different hydrothermal conditions and sand burial depths

Daily counts of germinated seeds of white saxaul (Haloxylon persicum) incubated at ۳۵ different hydrothermal environments (۱۰-۲۵?C and ۰ to -۳ MPa) were carried out under controlled laboratory conditions. The seeds were then buried in sand at ۴ different depths in well drained pots constantly moisturized for three weeks. In all these hydrothermal conditions, the courses of germination were completed in less than ۱۲ days. Both temperature and water deficit conditions significantly affected the seed germination. Water potential values of -۱.۵ MPa reduced the germination percentage to less than one fourth of the potential viability in all ambient temperature regimes and seed germination almost completely ceased at water deficit of -۳ MPa. As water potential decreased from ۰ to -۱.۵, base temperature values slightly increased from ۵.۴ to ۶.۵ ?C. 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Keywords:

Seed germination , hydrothermal time analysis , seed burial , Haloxylon persicum