Burial effects on seed germination and seedling establishment of Prosopis juliflora (SW.) DC

Abstract

Seed germination and seedling establishment are critical stages in plant life history, and both processes may be affected when buried under soil. Our aim was to investigate the effects of soil burial on the germination and seedling establishment of invasive Prosopis juliflora (Fabaceae). We studied the effects of burial, from soil surface to 4 cm deep, under greenhouse conditions and the effects of seed-storing in burial conditions at two depths (5 and 20 cm) and two storing periods (during 6 and 12 months) in field conditions. Soil burial limited the germination and the establishment of P. juliflora, which did not germinate at soil depths deeper than 3 cm. Some seedlings coming from seeds germinated at 2 cm, and every seedling at the soil surface and at 3 cm deep died. In contrast, survivorship of emerged seedlings was close to 90% between 0.5 and 2 cm depth. Seedlings developed the longest shoots at 1 cm deep, indicating that P. juliflora was able to get advantage at a moderate soil depth. Un-embedded seeds survived buried in the soil for months; however, their germination and the emerged seedling survivorship decreased after burial for 12 months.

Keywords:

• Gebel Elba National Park
• invasive species
• mesquite
• seeding emergence
• soil temperature

Acknowledgments

We thank Ahmed Mansour El Taher, Ibrahim Nasser, Mahmoud Fictor, and Mohamed Awadallah for help in the field and we thank Mansour Hussein for his assistance in the laboratory. We thank Gordon Davie for assistance in the English editing.