Effects of sand burial, soil water content and distribution pattern of seeds in sand on seed germination and seedling survival of Eremosparton songoricum (Fabaceae), a rare species inhabiting the moving sand dunes of the Gurbantunggut Desert of China

Abstract

Sand burial, persistent seed bank and soil water content (SWC) are three factors that potentially can affect regeneration in sand dune plant populations. To evaluate the effects of these three factors on population regeneration of Eremosparton songoricum, a rare and endangered legume, we investigated seed germination, seedling emergence and seedling survival in greenhouse and controlled field experiments in different sand dunes microsites. Freshly matured seeds are physically dormant, and the highest germination was only 9.3±5.8% at 25/10°C. Seed germination occurred at burial depths from 0 to 10 cm, but the maximum depth from which seedlings emerged was 6 cm; from 1 to 6 cm, the deeper the burial, the lower the percentage of seedling emergence. Only 36.2% of the total soil seed banks occurred at depths of 0-6 cm. For artificially sown seeds at different dune microsites, mean seedling emergence percentage was 6.8%. Of 150 seedlings that emerged in the field investigation at the study site, only those germinating in flat sandy areas survived, and mean survival percentage was only 2.0%. Thus, the proportion of non-dormant seeds in soil seed banks that developed into seedlings and survived to the end of the growing season was only 0.2%. Minimum SWC for seed germination, seedling emergence and seedling survival was 2.0%. During monitoring of emergent seedlings in the field, low seedling recruitment was at least partly due to the rate of root extension (1.6± 0.3 cm day −1 ) into the sandy soil, which was slower than that of the downward movement of plant-available moisture (2.8±0.6 cm day −1 ). Thus, population regeneration under natural conditions rarely occurred via Plant Soil (2011) 345:69-87

Effects of sand burial and overstory tree age on seedling establishment in coastal Pinus thunbergii forests in the northern Shandong Peninsula, China

“…3a). Liu et al (2011) and Zhu et al (2014) also found similar results and thought they were related to greater humidity (soil moisture) around these seeds in the top layer. The lowest seed germination rates at the 5 cm burial depth may be related to low oxygen in the sand (Vleeshouwers 1997) or the exhaustion of seed reserves during germination (Chen andMaun 1999, Liu et al 2011).…”

“…Burial depth has been demonstrated to have an effect on seed germination (Zhang and Maun 1994, Chen and Maun 1999, Li et al 2007, Guo et al 2010, Liu et al 2011, Redondo-Gómez et al 2011, Zhu et al 2014. For example, the highest seedling emergence for wildrye occurred at a 1-cm depth (Zhu et al 2014), whereas it was 2-cm for Pitcher's thistle (Chen and Maun 1999).…”

“…For example, the highest seedling emergence for wildrye occurred at a 1-cm depth (Zhu et al 2014), whereas it was 2-cm for Pitcher's thistle (Chen and Maun 1999). Seeds buried at appropriate depths may have higher germination rates than those on the surface (Chen and Maun 1999, Guo et al 2010, Liu et al 2011, Zhu et al 2014. However, excessive burial may prevent germination and subsequent seedling survival.…”

Influence of Different Longitudinal Dune Positions in the Gurbantunggut Desert on the Reproduction of Haloxylon Ammodendron Seedlings

“…1 and 2), Meanwhile, the harsh environmental conditions in deserts, such as drought, high temperature, and so on, result in high death rates. For example, the survival rate of Eremosparton songoricum (Fabaceae) in the Gurbantunggut Desert is only 2% (Liu et al, 2011). Haloxylon ammodendron is the dominant species in the Gurbantunggut Desert.…”

“…VPD indicates that the degree of atmospheric drought also controls the evaporation of surface soil water and the transpiration rate of vegetation. When atmospheric drought is severe, water evaporation loss on the surface soil of longitudinal dunes and water consumption of vegetation transpiration are higher (Liu et al, 2011). Consequently, the death rate of Haloxylon ammodendron seedlings will also be higher (Fig.…”