Effects Of Sand Burying On Seed Germination、seedling Emergence And Seedling Growth Of Pugionium Gaertn

Sand burial is a common phenomenon in sand dune ecosystems all over the world. Although many studies concerning the effects of sand burial on seed germination、 seedling emergence and seedling growth have been conducted in many parts of the world, such studies are rare in Pugionium cornutum(L.) Gaerth.and P. dolabratum Maxim.of Pugionium Gaertn. Experiments were conducted under controlled conditions in greenhouse to study the effects of sand burial and seed size on seed germination、seedling emergence and seedling growth of Pugionium cornutum(L.) Gaerth.and P. dolabratum Maxim. The results showed that sand burial depth had significant effects on seed germination and seedling emergence of Pugionium cornutum(L.)Gaerth. and P. dolabratum Maxim.The highest percentage of germinated seeds,emerged seedlings and emergence rate and the lowest percentage of dominated seed and dead seed occurred at2cm and4cm burial depth.Few seeds lying on the surface of the sand germinated, and those that did germinate, could not anchor their roots into the soil and seedlings did not establish successfully. As burial depth increased from8cm to16cm(Pugionium cornutum(L.) Gaerth.) and from4cm to16cm(P. dolabratum Maxim.), the percentage of seeds that germinated and emerged significantly declined, a higher number of seeds remained dormant, even dead. Seed size had also significant effect on seed germination and seedling emergence of Pugionium cornutum(L.)Gaerth. and P. dolabratum Maxim. For Pugionium cornutum(L.)Gaerth., at2to18cm burial depth,large seeds had higher percentage of germinated seeds,emerged seedlings and emergence rate and lower percentage of dominated seed and dead seed than medium and small seeds. For P. dolabratum Maxim., at2cm to8cm sand burial depths,the large seed germination and seedling emergence rate than medium-sized seeds and small seeds,however at greater depths (>12cm),seed size did not affect seed germination and seedling emergence.After sand burial, the result showed that slight burial could promote the growth of seedling, accelerate ramet growth and enhance the biomass and growth rate of whole plant,but intensive burial could lead the seedling to die. With burial depth increasing,stem biomass increased. Sand burial made the seedling to distribute more resources that be used to growth of aerial part,and the biomass ration of aerial part increased.After sand burial.the time to recover growth of seedling of P. Cornutum(L.)Gaertn. and P.dolabratum Maxim. was short, and the height of seedling.the biomass accumulation rate and cumulant were greater than that of small seed.