The biology and autecology of Nitraria L. in Australia. II. Seed germination, seedling establishment and response to salinity

摘要: Detailed investigations were undertaken to determine the requirements for optimal germination and establishment of Nitraria billardieri. Germination N. billardieri on Riverine Plain is aided considerably by prior ingestion fruit emu (Dromaius novaehollandiae). Experiments suggested that increase in emu-ingested seed largely a response removal saline outer pericarp during digestion. In one experiment, 62% germinated after 24 days compared with 6% hand-picked seed. Studies field populations seedlings indicated they are susceptible competition from cool season annual species. A experiment sand boxes between Atriplex vesicaria showed have slower growth rate be perennial A. vesicaria. Studies root extension nummularia observation demonstrated poor performance roots which grew only 53 cm 7 weeks whereas 160 4 weeks. These data suggest establishes successfully competes severely weakened saltbush stands. Other important factors availability 'safe sites’ degree species. Glasshouse experiments using culture both could survive salinities 0.9 M NaCl responded terms dry matter production low salt inputs (e.g. 0.3M NaCl) although decreased more rapidly as salinity increased.