Effects Of Winged Perianth Of Zygophyllum Xanthoxylum On Seeds Germination Under Controlled Conditions And Seeds Longevity In The Field

Seed appendage is important in seed germination.Its presence favor plant populations preservation and maintaining in extreme environments. Zygophyllum xanthoxylum is a key species in the arid and semi-arid area. Present research studied the effects of winged perianth of Z. xanthoxylum on seeds germination under controlled condition and on seeds longevity in the field. The results showed that:1 For the experiment under optimal condition, the germination percentage of Z.Xanthoxylum seeds with the winged perianth intact was 0; and germinated to 91% when the winged perianth was removed. It indicated that the winged perianth was the main reason causing seed dormancy.2 After treating with winged perianth water extracts, Seeds germination percentage of Z.Xanthoxylum, Reaumuria soongorica and Cleistogenes songorica. were not significantly affected by low concentration (0.025 g/mL) winged perianth water extracts, but were significantly reduced by high concentration(>0.025 g/mL). The effects of water extracts on the germination rate and the radicals length of three species seeds also varied with the water extracts concentrations: low concentration (0.025 g/mL) water extracts promoted radical growth of three species seeds, but high concentration inhibited its growth.3 With three temperature (10℃,20℃and 30℃) and two soil water content (10%, 20%), the germination of seeds with the winged perianth intact was significantly lower than that of the seeds with the winged perianth. Seeds germination percentage and gremination rate was the highest when temperature was 20℃and soil water content was 40%-60%.4 Seeds with the winged perianth and without the winged perianth were buried in different soil depth (0 cm, 2 cm, 5 cm)in the field one year and sampled every 2 months to test the germination in the field and the viability under controlled conditions, the results showed that: (1) More than 70% of seeds with the winged perianth and without the winged perianth placed on 0cm still remained viable and belonged to persistent soil seed bank, however, seeds buried in the 2cm and 5cm died or germination in the field and belonged to transient soil seed bank; (2) Seeds without the winged perianth geraiinatied earlier than that of seeds with the winged when buried in 2cm and 5cm , and the germination percentage was significantly higher than that of the seeds with the winged perianth except that in the Oct; ( 3) As the burial depth and time increasing, seeds with the winged perianth germination increased in the field and the dormancy ratio decreased; (4) The mortality rate of seeds without the winged perianth were significantly higher than that of the seeds with the winged perianth during burial period.